Amorphous character in twenty western Montana forest soils with apparent eolian influence
by Robert Joseph Ottersberg
A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
in Soils
Montana State University
© Copyright by Robert Joseph Ottersberg (1977)
Abstract:
Volcanic ash is a significant component of eolian deposits of Recent age in Western Montana. A
survey of soil scientists in this region indicated brown color, low bulk density and high silt content are
used by many respondents to recognize volcanic ash influence. Twenty forest soils were sampled and
characterized.
The soils represent Andept suborders, Andic and Andeptic subgroups and soils with apparent eolian
influence indicated by their morphology. Strong amorphous character was associated with a
combination of the following morphological properties: 1) high silt content, usually 60% or more; 2)
high chroma, usually four or more for Andept suborders, and three or more for Andic and Andeptic
subgroups; 3) weak consistence, usually soft, friable, nonsticky, nonplastic; 4) weak structural grade.
Nutrient content, cation exchange capacity and water holding capacity appear to be much larger in
andic soil with strong amorphous character than non-andic soil material when expressed on a weight
basis. On a volume basis, analysis of andic layers was not very different from other soil material with
similar textures. STATEMENT OF PERMISSION TO COPY
'
■
i
'
In p r e s e n tin g t h i s th e s is in p a r t i a l
f u l f i l l m e n t o f the
requirem ents f o r an advanced degree a t Montana S ta te U n i v e r s i t y ,
I agree t h a t th e L i b r a r y s h a ll make i t f r e e l y a v a i l a b l e f o r inspec­
tio n .
I f u r t h e r agree t h a t perm ission f o r e x te n s iv e copying o f t h i s
th e s is f o r s c h o l a r l y purposes may be granted by my m ajor p r o fe s s o r ,
o r , in h is absence, by the D i r e c t o r o f L i b r a r i e s .
I t i s understood
t h a t any copying o r p u b l i c a t i o n o f t h i s th e s is f o r f i n a n c i a l
s h a ll
not be a llow ed w ith o u t my w r i t t e n perm ission.
S ig n a tu re
gain
AMORPHOUS CHARACTER IN TWENTY WESTERN MONTANA
FOREST SOILS WITH APPARENT EOLIAN INFLUENCE
by
ROBERT JOSEPH OTTERSBERG
A th e s is subm itted i n p a r t i a l f u l f i l l m e n t
o f th e requirem ents f o r th e degree
of
MASTER OF SCIENCE
in
Soi I s
Approved:
C h a irp ers o n , Graduatev Committee
Head, M ajor Department
GraduatevDean
MONTANA STATE UNIVERSITY
Bozeman, Montana
May, 1977
iii
ACKNOWLEDGMENTS
I
would l i k e t o thank G erald N ie ls e n f o r h is v a lu a b le
guidance and continuous s u p p o rt.
Murray K la ges , th e Montana
S ta te S o il T e s tin g Lab and Hayden Ferguson a re thanked f o r the use
o f t h e i r la b o ra to ry f a c i l i t i e s .
S o il
Conservation S e r v ic e and
F o re st S e r v ic e s o i l s c i e n t i s t s have provided very u s e fu l observa­
t i o n s and a s s is ta n c e f o r which I am v e ry g r a t e f u l .
This th e s is would no t be p o s s ib le w ith o u t th e support and
encouragement o f my w i f e Mary Jane.
TABLE OF CONTENTS
■ Page
V I T A ...................................................................................
.
. .
ii
ACKNOWLEDGMENTS......................................................................................................... i i i
TABLE OF CONTENTS .
............................................................................................
LIST OF T A B L E S ............................................................................................
.
iv
. .
vi.
LIST OF FIG URE S .......................................................................................................... v i i i
A B S T R A C T ............................................................................................................... ' . .
INTRODUCTION
ix
. ..........................................................................................................
I
LITERATURE REVIEW................................................... V ............................................
Sources o f E o lia n Deposits in Western Montana ............................
V o lc a n ic Ash R ecognition in F o re s t S o i ls o f
th e Northern Rockies ...................................................................................
Genesis o f Ash-Rich Loess Mantles
........................................................
Taxonomic R ecognition o f V o lc a n ic Ash I n flu e n c e
.......................
2
2
MATERIALS AND METHODS . ........................................................................................
Survey o f S o il S c i e n t i s t s
..........................................................................
Sample S e l e c t i o n ............................................................................................ .
P r e p a r a tio n o f S a m p l e s ..................................................................................
Chemical and P hysical A n a l y s i s ....................................
A n a ly s is o f D a t a .................................................................................................
9
9
9
11
15
19
5
6
7
RESULTS AND DISCUSSION ........................................................................................... 20
Survey o f S o il S c i e n t i s t s ..........................................................................
20
Taxonomic Grouping o f Amorphous C h a ra c te r ............................................. 23
Amorphous C h a ra c te r In d ic a t e d by Clay M ine ralogy .......................
28
M orphological In d ic e s o f Amorphous C l a y s .......................... . . ,
32
Amorphous C h a ra c te r and Chemical P r o p e r t ie s
......................................... 37
Amorphous C h a ra cte r and Physical P r o p e r t ie s
.................................
44
D i s t r i b u t i o n o f Amorphous C h a ra c te r in Montana ............................
48
SUMMARY................................
51
CO NCLUSIO N.................................................................... .......... ...................... ....
53
V
Page
A P P E N D IC E S ....................................................................................................................
Appendix I .
Responses to the Survey on V olcanic
Ash In flu e n c e d S o i ls in Montana and Parts
o f Idaho ................................................................................................. .... . .
Appendix 2.
Pedon D e s c rip tio n s
. ..............................................
Appendix 3.
Lab o rato ry D a t a .......................
Appendix 4.
Unpublished P r e l i m i n a r y Data from
th e S o il Conservation S e r v i c e ................................
Appendix 5.
P la n t A b b r e v ia tio n Code ...................................................
54
109
119
LITERATURE C I T E D .....................................................................
120
55
77
95
vi
LIST OF TABLES
Table
1
Page
Three Brown P o d z o lic S o ils w it h Apparent
E o lia n D e p o s itio n ...................................................................................
2
C l a s s i f i c a t i o n and Source o f S o il Samples .................. ....
3
S i t e C h a r a c t e r i z a t i o n ...............................................................................
12.
4
Sample L oc ation Code
f o r F ig u re 2 ..................................................
14
5
C r i t e r i a f o r Ranking and Grouping S tre n g th
o f Amorphous C h a ra c te r
.....................................................................
24
6
7
8
9
10
11
12
13
14
. .
3
Order o f Amorphous C h a ra c te r and Taxonomic
R e c o g n i t i o n ........................................................................................ ; .
Physical and Chemical In d ic e s o f Amorphous
C h a r a c te r , Group I
. . .................................................................
10
24
.
25
P hysical and Chemical In d ic e s o f Amorphous
C h a r a c te r , Group 2 ..................................................................
27
P hysical and Chemical In d ic e s o f Amorphous
C h a r a c te r , Group 3 ................................................................................
28
I n t e r p r e t a t i o n s o f X -r a y D i f f r a c t i o n P a tte rn s
o f Eleven Study S i t e s ............................................................ . . . .
30
M orphological Data Associated w it h Amorphous
C h a r a c te r , Group I
................................................................................
35
M orphological Data Associated w it h Amorphous
C h a r a c te r , Group 2 ...............................................................................
36
M orphological Data Associated w ith Amorphous
C h a r a c te r , Group 3 ..................................................................
37
Mean Chemical P r o p e r t ie s o f Andie ( a ) and
S u bjacent (b ) Horizons w i t h i n 25 cm ...................
38
. . . . .
Vl I
Table
15.
Page
E f f e c t s o f T e x tu re on C o n tra s t Between
P r o p e r t ie s o f Andie and B uried S o i l ....................... .
39
S o il Samples used f o r Phosphorus S o rp tio n
" I s o t h e r m s " ............................................................................................
43
Mean Physical P r o p e r t ie s o f Andie ( a ) and
S u b jac e n t (b ) Horizons w i t h i n 25 c m .....................................
47
18
Code to Respondents' P o s it io n and L o c a t i o n ............................
76
19
Chemical P r o p e r t ie s by Horizon . . . . . . .
........................
95
20
Physical P r o p e r t ie s by Horizon ........................................................
97
21
Andept Suborders and Andie o r Andeptic
Subgroups Recognized by the SCS in M o n t a n a ....................... 109
16
17
v iii
LIST OF FIGURES
Figure
1
Page
Recent V o lc a n ic Ash which was Deposited
in M o n t a n a .................................................................................................
2
D i s t r i b u t i o n o f Sampling S i t e s
3
X -r a y D i f f r a c t i o n P a tte rn s o f T r u e f i s s u r e ................................. .
29
4
Comparison o f CEC on a Weight and Volume
Basis f o r T r u e f i s s u r e ..........................................................................
40
5
Phosphorus S o rp tio n "Isotherm s"
....................................................
42
6
Comparison o f Water Holding C a p a c itie s on a
Weight and Volume Basis f o r E lk n e r v -2
. . ........................
45
Comparison o f Water Holding C a p a c itie s on a
Weight and Volume Basis f o r T r u e f i s s u r e . .
46
7
8
9
.................................
4
.
. . . . .
.
.
.
13
.
Estim ated D i s t r i b u t i o n o f S o ils w ith Amorphous
C h a ra cte r in M o n t a n a ............................................................
50
X -r a y D i f f r a c t i o n P a t t e r n s , Buckhouse ..........................................
100
10
X -r a y D i f f r a c t i o n P a t t e r n s , T r u e f i s s u r e ............................ ....
.
101
11
X -r a y D i f f r a c t i o n
P a t t e r n s , C abinet ................................................
102
12
X -r a y D i f f r a c t i o n
P a t t e r n s , Krause
103
13
X -r a y D i f f r a c t i o n
P a t t e r n s , S u g a r lo a f I
14
X -r a y D i f f r a c t i o n
P a t t e r n s , S pring Emery
15
X -r a y D i f f r a c t i o n
P a t t e r n s , H ilg a r d
................................................
106
16
X -r a y D i f f r a c t i o n
P a t t e r n s , S u g a rlo a f 2 .......................................
107
17
X -ra y D i f f r a c t i o n
P a t t e r n s , E lk n e r
108
................................................
.......................................
104
. . . . . . . .
105
................................................
ix
ABSTRACT
V o lc a n ic ash i s a s i g n i f i c a n t component o f e o l ia n deposits
o f Recent age in Western Montana.
A survey o f s o i l s c i e n t i s t s in
t h i s re g io n i n d ic a t e d brown c o l o r , low bulk d e n s ity and high s i l t
c o n te n t a re used by many respondents to recognize v o lc a n ic ash
in flu e n c e .
Twenty f o r e s t s o i l s were sampled and c h a r a c t e r iz e d .
The s o i l s r e p r e s e n t Andept s uborde rs , Andie and A ndeptic subgroups
and s o i l s w ith a p parent e o l ia n i n f l u e n c e in d ic a te d by t h e i r
morphology.
Strong amorphous c h a r a c t e r was a s s o c ia te d w ith a combi­
n a tio n o f th e f o l l o w i n g m orphological p r o p e r t i e s :
I ) high s i l t
c o n te n t, u s u a l l y 60% o r more; 2) high chroma, u s u a lly fo u r o r more
f o r Andept su b o rd e rs , and th r e e o r more f o r Andie and A ndeptic sub­
groups; 3) weak c o n s is te n c e , u s u a lly s o f t , f r i a b l e , n o n s tic k y ,
n o n p l a s t ic ; 4) weak s t r u c t u r a l grade.
N u t r i e n t c o n t e n t , c a tio n
exchange c a p a c ity and w a te r h o ld in g c a p a c ity appear to be much
l a r g e r in andic s o i l w ith strong amorphous c h a r a c te r than non-andic
s o i l m a t e r i a l when expressed on a w eig h t b a s is .
On a volume b a s i s ,
a n a ly s is o f andic l a y e r s was not v ery d i f f e r e n t from o t h e r s o il
m a t e r i a l w ith s i m i l a r t e x t u r e s .
INTRODUCTION
S i l t r i c h horizons cover many f o r e s t s o i l s o f Western Montana
E o lia n d e p o s its c o n t r i b u t i n g to t h i s l a y e r in c lu d e loess and v o lc a n ic
ash.
V o lc a n ic ash in flu e n c e d s o i l s a re considered im p o rta n t f o r
p l a n t growth by some whereas o th e rs say th e y a re no more im p o rta n t
than any o t h e r f o r e s t s o i l .
In a w e ll d ra in e d s i t e w it h a cool humid c l i m a t e , v o lc a n ic
ash can be expected to w eather t o form the amorphous c la y m ineral
a llo p h a n e .
D i s t i n c t i v e p r o p e r tie s o f t h i s c la y m in era l a re used to
determ ine i t s presence f o r c l a s s i f i c a t i o n purposes in S o il Taxonomy.
P r o p e r t ie s such as high w a te r h o ld in g c a p a c i t y , l a r g e pH dependent
charge and th e a b i l i t y to complex o rg a n ic m a tte r may s i g n i f i c a n t l y
a ffe c t f e r t i l i t y
o f s o i l s c o n ta in in g amorphous c la y s .
The o b j e c t o f t h i s study is to a n aly ze Western Montana f o r e s t
s o i l s w i t h apparent e o l i a n d e p o s its and probable amorphous c h a ra c te r,
and to c l a r i f y th e f o l l o w i n g q u e stio n s:
1)
Is amorphous c h a r a c te r found in a l l
apparent e o l i a n mantles?
f o r e s t s o i l s w ith
I f s o , is i t stro n g enough f o r taxonomic
r e c o g n it io n ?
2)
Can amorphous c h a r a c t e r be determ ined in th e f i e l d by
using m orphological c h a r a c t e r i s t i c s ?
3)
Does amorphous c h a r a c t e r r e l a t e to any p h y sic a l or
chemical p r o p e r t i e s o f the s o i l ?
LITERATURE REVIEW
Sources o f E o lia n Deposits in Western Montana
Two types o f wind blown d e p o s its were im p o rta n t in Western
Montana in r e c e n t t i m e s ; loess and v o lc a n ic ash.
c ia t e d w it h g l a c i a l
s ilt
(1 1 ).
Loess i s u s u a lly asso­
G l a c i e r - f e d r i v e r s l i k e the G a l l a t i n ,
Madison, and B i t t e r r o o t provided much o f the s i l t d e p o s ited in areas
th e y flowed through ( 4 ) .
Loess d e p o s its were not l i m i t e d to the
v a l l e y s , bu t extended i n t o nearby mountains such as th e Sapphire
Mountains e a s t o f th e B i t t e r r o o t V a l l e y ( 3 9 ) .
S i l t r i c h s u rfa c e
mantles r e s u l t i n g from B i t t e r r o o t loess were found in s o i l
s e r ie s
l i k e Holloway and T r a p p e r , both p r e v io u s ly c l a s s i f i e d as Brown
P o d z o lics.
M ine ralogy o f the Holloway s e r ie s from the Ninem ile
Canyon area no rth o f M issoula showed t h a t s i l t o f the s u r fa c e horizons
was o f a d i f f e r e n t o r i g i n than r e s id u a l
low er horizons ( 4 4 ) .
q u a r t z i t e and a r g i l l i t e
of
Though e a r l y s tu d ie s o f Brown P o d z o lic s o i ls
in the Northern Rockies d id n o t re co g n ize the in f lu e n c e o f l o e s s , i t s
presence is suggested by the l a r g e amounts o f s i l t and very f i n e sand
in upper horizons o f some pedons (T a b le I ) .
O ther sources o f loess a re d e s e r t and a e r o s o li c dust ( 1 6 ) .
D esert dust d e p o s itio n was expected to have been high from 4 ,0 0 0 to
8 ,0 0 0 y ea rs ago d u rin g the a l t i thermal o r h y p s ithermal
29).
in te rv a l
(15,
V o lc a n ic ash de pos ited d u rin g t h i s warm, dry p e rio d has. been
found sandwiched between l a y e r s o f loess in Saskatchewan ( 9 ) .
Upper
horizons o f Palouse loess c o n ta in s i g n i f i c a n t q u a n t i t i e s o f v o lc a n ic
3
Table I .
Three Brown P o d zo lic S o ils w ith Apparent E o lia n D e p o s it i o n .*
Pend O r i e l l e loam
Bonner County, ID
Waits g r a v e l l y loam
F lathead County, MT
Unnamed
G l a c i e r County, MT
depth
(cm)
depth
(cm)
depth
(cm)
0
s i+ v fs
(%)
s i+ v fs
(%)
s i+ v fs
(%)
-
0 .6
76
0
-
0 .6
66
0
0 .6 -
1 .9
80
0 .6 -
3 .1
64
1 .3 -
75
3 . 1 - 13
66
1 . 9 - 10
-
1 .3
63
8
58
8
- 23
56
10
- 25
76
13
- 28
65
23
- 43
55
25
- 38
70
28
- 75
58
43
- 68
46
38
- 50
57
75
-110
28
68
- 88
26
50
- 78
54
88
- 118
47
78
-1 2 8
39
118
- 150
53
*from S o il
Survey Lab Memorandum #1 ( 3 8 ) .
ash ( 3 0 ) .
During the a l t i therm al, ash could have been deposited in the
Rocky Mountains w ith d e s e r t d u s t, a f t e r i n i t i a l
d e p o s itio n on the
Palouse p r a i r i e s .
Primary de pos its o f v o lc a n ic ash from a t l e a s t th r e e Cascade
Range volcanoes are found in Western Montana ( F i g .
I).
Washington erupted near the end o f the Wisconsin g l a c i a l
1 2,000 years ago ( 1 3 ) .
G l a c i e r Peak,
perio d about
Mount Mazama ( C r a t e r L a k e ), Oregon e je c te d an
4
Figure I .
Recent v o lc a n ic ash which was deposited in M ontana.*
*Adapted from Lemke e t a I
' 7 5 , Okazaki e t a I
17 2, Smith e t aI
'68
5
e s tim a te d 30 cubic k ilo m e te r s o f te p h ra over s e v e ra l s t a t e s in the
P a c i f i c Northwest about 6 ,5 0 0 years ago ( 4 7 , 2 8 ) .
Mount S t . Helens,
Washington de pos ited ash near th e northw estern c orner o f Montana
a t l e a s t t h r e e times in th e l a s t 4 ,0 0 0 y e a r s .
These a s h f a l l s in c lu d e
the Mount S t . Helens Y (3 , 4 0 0 y e a rs o l d ) , W (400 to 500 y ea rs o ld )
and T (about 180 y ea rs o l d ) e ru p tio n s ( 2 6 , 3 5 ) .
'
A s h f a ll W i s only
a n t i c i p a t e d in Montana now ( 3 6 ) .
V o lc a n ic Ash Recognition in F orest S o ils
o f th e N orthern Rockies
In 1960, v o lc a n ic ash was re p o rte d i n upper horizons o f
mountain s o i l s o f Northern Idaho ( 3 3 ) .
Since then v o lc a n ic ash
has been recognized in many f o r e s te d s o i l s o f Western Montana.
S o il
Conservation S e r v ic e (SCS) s tu d ie s in 1963 re p o rte d from 60 to 80%
v o lc a n ic glass in th e sands o f s u rfa c e horizons o f th e Holloway s e r ie s
from a s i t e
in Missoula County (Appendix 4 ) .
That much glass in s u r­
fa c e horizons has been re p o rte d in o n ly one o th e r p la c e in Western
Montana f o r e s t s o i l s .
Northwest o f Missoula in the Savenac Nursery,
60% gla ss was found i n the s u rfa c e h o rizo n o f one s i t e
(2 5 ).
Most
s o i l s s tu d ie d had o n ly 5 to 10% g l a s s , u s u a l l y c o n ce n tra te d in upper
horizons o f s o i l
(Appendix 4 ) .
Most Montana s o i l s w it h s i g n i f i c a n t
glass c o n te n t were once c l a s s i f i e d as Brown Podzoli c s .
S o il
s e r ie s a ls o c o n ta in in g s i g n i f i c a n t glass inclu d e d th e T a r k i o,
6
Greenough, Loberg and P h i l l i p s b u r g s e r i e s i n Missoula County
(Appendix 4 ) .
V o lc a n ic ash contents a re h ig h e r in the western por­
t i o n o f th e Northern Rocky Mountains.
In Northern Id a h o , Brown
P odzolics had ash contents as high as 72 to 80% ( 1 4 ) .
To the e as t
o f M issoula County, i n G l a c i e r County, o n ly I to 3% v o lc a n ic ash was
found i n th e upper horizons o f any s o i l
s tu d ie d (Appendix 4 ) .
Genesis o f Ash-Rich Loess Mantles
V o lc a n ic ash w i l l
r e a d i l y w eather to form the amorphous c la y
m inera l a llo p h a n e when th e s i t e is w e ll d ra in ed ( 2 ) .
M o n t m o r illo n ite
c la y s form when d ra in a g e i s poor as in closed basins ( 2 , 8 ) .
In
Nova S c o t i a , small amounts o f a llo p h a n e have formed i n loess w ith o u t
the presence o f v o lc a n ic ash ( 7 ) .
The d is o rd e re d arrangement o f
loess p a r t i c l e s and a cool humid environment a s s o c ia te d w ith
p o d z o l i z a t i o n were thought to be th e reason f o r a llo p h a n e fo rm a tio n
th e re ( 7 ) .
In New Z e a la n d , loess r i c h in v o lc a n ic ash has r e s u lte d
i n th e fo r m a tio n o f a llo p h a n e in a cool humid environment ( 3 1 ) .
In Montana and p a rts o f a d ja c e n t Idaho and A l b e r t a , allophane
has formed in th e cool humid environm ent o f c o n i f e r f o r e s t s .
much as 60% a llo p h a n e was found in ash in flu e n c e d s o i l
Experim ental
F o re s t ( 1 9 ) .
As
o f the Coram
Amorphous c la y s were p r e d ic te d f o r moun­
ta in o u s areas no rth and west o f M issoula County which had ash
in flu e n c e d s o i l s
(1 8 ).
Eleven s o i l
s e r i e s in the S t .
R e g is-N in em ile
7
area o f M in e ra l County were thought to have a llo p h a n e p re s e n t ( 4 5 ) .
Three s o i l s from M in e ral and M issoula Counties analyzed a t the SCS
L in c o ln lab were dominated by amorphous m a t e r ia l
(Appendix 4 ) .
Two
o f those th r e e were used in t h i s s tu d y ; th e Buckhouse and Wishard.
Amorphous clays dominate a loess r i c h f o r e s t s o i l
contained 50% v o lc a n ic glass ( 2 7 ) .
Idaho B a t h o l i t h ,
In w e ll
in A l b e r t a which
dra in ed s i t e s o f the
amorphous clays dominated "loess" m antled s o i l s
(8 ).
Taxonomic R ecognition o f V o lc a n ic Ash I n f lu e n c e
In Montana, v o lc a n ic ash i n f lu e n c e is recognized a t th re e
l e v e l s o f S o il Taxonomic c l a s s i f i c a t i o n ; s u b o rd e r, subgroup and
f a m i ly ( 4 3 ) .
nant s o i l
At th e suborder l e v e l , where v o lc a n ic ash i s the domi­
form ing f a c t o r , c l a s s i f i c a t i o n is based on th e dominance
o f v o lc a n ic glass o r th e amorphous clays which form as gla ss weathers
(4 3 ).
These s o i l s a re c a l l e d Andepts.
i n f l u e n c e a t the subgroup l e v e l
a ss o c iate d w ith amorphous c la y s .
C l a s s i f i c a t i o n o f ash
is based on the presence o f p r o p e r tie s
S o i ls w ith secondary bu t im porta nt
ash i n f l u e n c e have Andie o r A ndeptic name m o d i f i e r s .
At the fa m ily
l e v e l o f c l a s s i f i c a t i o n s i g n i f i c a n t q u a n t i t i e s o f glass are recognized
by the name "ashy."
The w ea th e rin g products are recognized by the
names medial o r t h i x o t r o p i c .
Medial s o i l s are dominated by amorphous
clays and t h i x o t r o p i c s o i l s have d i s t i n c t i v e physical p r o p e r t ie s not
r e s t r i c t e d to w ea th e rin g products o f v o lc a n ic g la s s .
8
In Montana, th r e e Andept s o i l
s o il
s e r ie s and 20 Andie o r Andeptic
s e r ie s have been recognized by the SCS (Appendix 4 ) .
Many o f
these s o i l s were p r e v io u s ly c l a s s i f i e d as Brown P odzolics (Appendix
4 ).
A l l bu t th e Hebgen s e r i e s appear t o be r e l a t e d to loess r i c h in
v o lc a n ic ash.
The Hebgen s e r ie s formed in a l l u v i a l
by o b s id ia n gla ss sand and g ra v e ls
de pos its dominated
(1 8 ).
V o lc a n ic ash in flu e n c e d s o i l s a re thought to occur in s ev e ral
p a r ts o f Northwestern Montana.
Sanders, M i n e r a l , and R a v a l l i
(3 8 ).
Andepts a re p r e d ic te d i n L in c o ln ,
Counties in the N ational. S o ils A tla s
Recognition o f ash r i c h loess mantles on the Spotted Bear
D i s t r i c t was as Andie o r Andeptic subgroups ( 2 4 ) .
S i m i l a r in flu e n c e
occurs on the Lower B la c k fo o t area o f M issoula County ( 4 2 ) .
was recognized as probably being p re s e n t in s e v e ra l s o i l
S t.
Allophane
s e r ie s in the
R e g is -N in e m ile a rea o f M in e ra l County ( 4 5 ) .
According to ash f a l l
area has th e p o t e n t i a l
d is trib u tio n s
(F ig .
I),
a much l a r g e r
f o r v o lc a n ic ash in flu e n c e d s o i l s .
MATERIALS AND METHODS
Survey o f S o il
F o re st and s o i l
S c ie n tis ts
re se a rch e rs do no t com p lete ly agree upon the
o r i g i n , d i s t r i b u t i o n , p r o p e r t i e s , and importance o f v o lc a n ic ash in
Western Montana s o i l s .
T h e r e f o r e , in August, 1974, a telephone survey
was i n i t i a t e d and q u e s tio n n a ir e s were d i s t r i b u t e d to supplement a
re vie w o f l i t e r a t u r e on v o lc a n ic ash in flu e n c e d s o i l s
i n the re g io n .
Because a p o t e n t i a l l y l a r g e area o f the Northern Rockies is a f f e c t e d ,
a p rim ary o b j e c t i v e was d e te rm in in g how s o i l s c i e n t i s t s
v o lc a n ic ash in flu e n c e d s o i l
recognize
and what they understand about i t s
n a tu r e .
S o il
Conservation S e rv ic e and F o re s t S e rv ic e S o il
s c ie n tis ts
r e p r e s e n t many y e a rs o f e xp e rien ce w it h Western Montana and Northern
Idaho s o i l s where ash i n f l u e n c e i s re c o g n ize d .
These and o th e r
s c i e n t i s t s were c onta cted by phone and l a t e r by l e t t e r f o r con firm a ­
t i o n o f the o r a l d is c u s s io n .
in the survey a re l i s t e d
Responses t o the seven to p ic s covered
in Appendix I along w ith respondents'
names.
A summary is found on page 20.
Sample S e le c tio n
Sampling s i t e s in c lu d e seven c o l l e c t e d f o r SCS l a b o r a to r y
c h a r a c t e r i z a t i o n , fo u r s e n t to Murray Klages f o r c h a r a c t e r i z a t i o n , and
nine c o l l e c t e d f o r t h i s study w ith th e h e lp o f s o i l s c i e n t i s t s f a m i l ­
i a r w it h th e a rea o f c o l l e c t i o n
(T a b le 2 ) .
Of t h e s e , f i v e were Andepts
10
Table 2 .
C l a s s i f i c a t i o n and Source o f S o il Samples.
S i t e Name
C la s s ific a tio n
Source
Buckhouse
Typic Cryandept
SCS S 64 Mt
T r u e fis s u r e
E n tic Cryandept
SCS S 64 Mt
Unnamed 3
E n tic Cryandept*
M. K lages-L.
Keunnen
Unnamed 4
E n tic Cryandept*
M. K la g es -L .
Keunnen
E l kner
Andie Cryochrept
SCS S 74 Mt
Felan
Andie Cryochrept
SCS S 70 Mt
Holloway
Andie Cryochrept
SCS S 70 Mt
Krause
Andie Ustochrept
RJO Coram Study Area
Cabinet
Andeptic C r y o b o r a lf
RJO Nimlos Study Area
E lk n e r v
Andie C ry o c h rep t*
D. Ruppert-RJO
E lk n e r v -2
Andie C ry o c h re p t*
D. Ruppert-RJO
H ilg a r d
Andie C ry o c h rep t*
C. Davis
Holloway v
Andie C ry o c h rep t*
R. Poff-RJO
S pring Emery
Andie C ry o c h rep t*
D. Shay-RJO
S u g a rlo a f I
Andie C ry o c h rep t*
D. Shay-RJO
S u g a rlo a f 2
Andie C ry o c h rep t*
D. Shay-RJO
Unnamed I
Andie Cryochrept
M. Klages-H. H o ld o rf
Unnamed 2
Andeptic C r y o rth e n t
M. Klages-H.
Unnamed 5
F lu v e n t ic E u tr o c r e p t
SCS S 74 Mt
Wishard
Aquic C ry o b o ro lI
SCS S 64 Mt
+ T e n ta tiv e c l a s s i f i c a t i o n
H o ld o rf
11
o r Andie Cryochrepts based on l a b o r a t o r y determ ined c r i t e r i a .
Other
samples had ap p are n t v o lc a n ic ash i n f l u e n c e i n d i c a t e d by m orphological
c h a r a c t e r i s t i c s such as high s i l t c o n t e n t , d i s t i n c t low er boundary,
brown c o l o r , low b u lk d e n s i t y , and d i s t i n c t i v e f e e l
(see Survey o f
S o il S c i e n t i s t s , P. 2 0 , 5 8 ) .
Though a wide range o f s o i l
form ing f a c t o r s a re re p r e s e n te d ,
most s o i l s a re from c o n i f e r f o r e s t s i t e s
from
an
a lp in e p a r k la n d .
(T a b le 3 ) .
The Buckhouse i s
Residual p a r e n t m a t e r i a l s below th e e o l ia n
m antles v a r ie d from q u a r t z i t e and a r g i l l i t e
to g r a n i t e s , b a s a lts and g l a c i a l
from th e B e l t Supergroup
l a k e sedim ents.
Only C a b in e t;
Krause and Unnamed 5 were not from mountain slope p o s itio n s but from
fans o r t e r r a c e s .
c l i m a t i c ty p e s .
The a e r i a l d i s t r i b u t i o n re p re s e n te d two major
Northern lo c a t io n s f e l t a strong m a ritim e in flu e n c e
w ith 75 to 200 cm (30 t o 80 i n ) annual p r e c i p i t a t i o n .
The e a s t and
southern l o c a t i o n s a r e more c o n t i n e n t a l w it h p r e c i p i t a t i o n s from 50
to 100 cm (20 to 40 i n )
(4 6 )
(F ig .
2 ).
P r e p a r a tio n o f Samples
Samples c o l le c t e d by th e SCS f o r c h a r a c t e r i z a t i o n were p re ­
pared according t o s tandard procedures ( 3 6 ) .
c h a ra c te ris tic s o f a ll
(Appendix 2 ) .
M orphological
o th e r samples were recorded in th e f i e l d
A l l samples were a i r d r ie d
at
IOO0 F, then crushed,
ground and passed through square 2 mm s ie v e h o l e s .
12
Table 3.
S ite C h a ra c te riz a tio n .
S i t e Name
P arent M a t e r i a l * Slope Aspect E le v a tio n V e g e t a t i o n * *
(%)
(m)
Buckhouse
q u a rtz ite ,
a r g illite
Cabinet
50
S
2134
g la c ia l
la c u s trin e ,
mi xed
3
W
720
E lk n e r
g ra n ite
5
N
1585
E lk n e r v-1
g ra n ite
20
NE
-
A b la /va s c
E lkn e r v -2
g r a n i te
27
N
-
A b la /A ls i
Felan
calcareous
a rg illite
47
E
1749
P i e n / vagi
H ilg a rd
g ra n ite
15
E
-
Holloway
q u a rtz ite ,
a r g illite
18
NE
1371
Laoc1Psme/
Holloway v
q u a rtz ite
35
NE
2362
A b la /X e te
Krause
q u a rtz ite ,
a rg illite
30
N
1097
Thoc1A b la 1P ie n /
40
NE
2073
A bla/M efe
S pring Emery a n d e s ite
A b la /(p a rk la n d )
Juoc1Abgr/
Abl a /
(A lp in e t u r f )
S u g a rlo a f I
b a s a lt
25
NE
2097
A b la /A ls i-v a s c
S u g a rlo a f 2
b a s a lt
20
NE
2100
A b l a 1Psme/Aruv
T ru e fis s u re
a rg illite
30
SW
1508
A b l a 1P ie n /
Unnamed I
Ii m e s t o n e , shale
-
NW
1798
P ic o /
Unnamed 2
s h a le ,s ilts to n e
40
N
1737
A b l a 1P ie n /
Unnamed 3
a rg illite ,ig n e o u s
-
-
1341
Juoc/Clun
Unnamed 4
a rg illite
-
-
1280
Abgr/Clun
Unnamed 5
la c u s t r in e ,m ix e d
I
N
963
Wishard
a r g illite
40
N
1524
—
J uoc1P ie n /
U n d e r l y i n g p a re n t m a t e r ia l
**dom inant o v e r s to ry /d o m in a n t u n d e r s to r y ; see Appendix 5.
13
THOMPSON P4 l l s
G fffA r p a l l s
Figure 2.
D i s t r i b u t i o n o f sampling s i t e s .
14
Table 4.
Sample Location Code f o r F ig u re 2.
Number
Name
I
Buckhouse
2
Unnamed 3
3
Unnamed 4
4
T r u e fis s u r e
5
Wishard
6
Felan
7
Holloway
8
Spring Emery
9
S u g a rlo a f I
10
E lk n e r v -2
11
Cabinet
12
Krause
13
E lkn e r v-1
14
Unnamed 5
15
S u g a rlo a f 2
16
H ilg a rd
17
Holloway v
18
E l kner
19
Unnamed 2
20
Unnamed I
15
Chemical and Physical A na lys is
C h a r a c t e r i z a t i o n was completed in fo u r s e p a ra te l a b o r a to r ie s ,
by s e v e ra l d i f f e r e n t people.
Procedural v a r i a t i o n is e x p la in e d below
and recorded in the d a ta ta b le s
(Appendix 3 ) .
Mechanical a n a ly s is was done w ith 20 gram samples and
Anderson's 1963 method o f o rg a n ic m a tte r removal and d is p e r s io n ( I ) .
The p i p e t t e method was used to determ ine f i n e e a r t h f r a c t i o n s
41).
(1 0 ,
Samples done in SCS labs used hydrogen peroxide f o r org a n ic
m a tte r removal and sodium hexametaphosphate f o r d is p e r s io n ( 4 1 ) .
Samples from nine s o i l
s i t e s chosen f o r X -r a y d i f f r a c t i o n a n a ly s is
were c o l l e c t e d from s o i l
c y l i n d e r s used in mechanical a n a l y s is .
This
was done by ta k in g a 50 to 75 ml sample from the top 15 cm o f the
suspension in th e c y l i n d e r when only c la y remained in t h a t p o r t io n .
One h a l f o f t h i s sample was s a t u r a t e d w it h s a l t s o f magnesium (Mg)
and one h a l f w ith those o f potassium (K ) .
To s a t u r a t e th e c la y s ,
th r e e washings o f IN magnesium c h l o r i d e (MgClg) and IN potassium
c h l o r id e
(K C l) were fo llo w e d by c e n t r i f u g a t i o n and d e c a n ta tio n .
Excess s a l t s were removed w ith a w a te r wash f o r M g -s a tu ra te d clays and
a 60% methanol s o l u t i o n f o r K -s a tu r a te d c la y s .
Clays were mounted on
glass s l i d e s a f t e r making a t h i c k c la y suspension in w a te r and d r i p ­
ping t h i s
in a r e l a t i v e l y uniform thic k n e s s over th e s l i d e .
M g -s a tu ra te d c la y s were s o lv a te d w ith e th y le n e g ly c o l
A i r dry
by h e atin g f o r
16
fo u r hours in the presence o f e th y le n e g l y c o l .
P o ta s s iu m -s a tu ra te d
samples were f i r s t heated to 350 degrees C e ls iu s .
X -r a y d i f f r a c t i o n
p a tte r n s were o b ta in e d and the s l i d e s were then heated to 500 degrees
C e ls iu s .
D i f f r a c t i o n p a tte r n s were o b ta in e d between 2 and 30 degrees
20 f o r Mg-s a t u r a t e d samples and between 2 and 15 degrees 20 f o r both
K -s a tu r a te d c la y tr e a tm e n ts .
I n t e r p r e t a t i o n o f X -ra y d i f f r a c t i o n
p a tte r n s used Jackson's (1 7 ) guide to the basal spacings o f dominant
c la y m in e ra ls o f s o i l s .
Areas under d i f f r a c t i o n curves were estim a te d
so a r a t i n g o f r e l a t i v e abundance could be given to each major c la y
m i n e r a l.
The procedure o f th e SCS R iv e r s id e la b o r a t o r y f o r sample
p r e p a r a tio n was the same, but ceramic t i l e s were used in s te a d o f
glass s l i d e s f o r mounting samples.
D e te rm in a tio n o f 15 atmosphere w a te r holding c a p a c ity was done
w i t h a pressure membrane a p p ara tu s .
A pressure cooker and porous
p l a t e were used to determ ine 1 /3 atmosphere w a te r h o ld in g c a p a c ity .
Both d e te rm in a tio n s used s o i l
screen.
samples which had passed an 18 mesh
Analyses done in SCS labs were s i m i l a r .
Two d i l u t i o n s o f s o i l samples w it h w a te r were used in mea­
s u rin g pH; a 1:1 s o i l
to w a te r r a t i o f o r a l l
to w a te r r a t i o f o r SCS samples and a 1 :2 s o i l .
o th e r s .
Organic carbon was determ ined in the SCS l a b o r a t o r i e s w ith
the Acid Dichromate d i g e s t io n method ( 4 1 ) .
Other samples, ana­
ly z e d in the Montana S t a t e U n i v e r s i t y S o il T e s tin g L a b o r a to r y , used
17
a modified version o f the same procedure using a co lo rim e tric instead
of t it r a t io n methods to measure organic carbon (3 4 ).
T o ta l n itr o g e n d e te r m in a tio n used the K je ld a h l d ig e s t io n
method f o r SCS samples and the M icro K je ld a h l method m o d ifie d from
Bremner ( 6 ) f o r o th e r samples.
A v a il a b l e
phosphorus
was done w it h the Bray #1 method
m o d ifie d by Smith ( 3 7 ) .
Exchangeable bases were e s tim a te d w ith an ammonium a c e ta te
e x tra c tio n .
S o lu b le s a l t c o n te n t was c o rre c te d f o r on SCS samples
but no t on any o t h e r s .
E le c tric a l
c o n d u c tiv ity o f a 1: 2 s o il
to
w a te r r a t i o was determ ined to i n d i c a t e p o s s ib le need to c o r r e c t f o r
s a lts .
Flame photometry o r atomic a b s o rp tio n spectrophotom etry were
used to measure Ca++, Mg++, Na+, and K+.
The minor elements copper, i r o n , manganese and z in c were
determ ined by the DTPA-TEA e x t r a c t i o n o f Lindsay and Norvel
as. m o d ifie d by the. MSU S o il T e s tin g Lab.
(2 1 )
The P e rk in -E lm e r 290-B
atomic a b s o rp tio n s p e c tro p h o to m e te r, w it h lamps f o r Fe, Mn, Ca, and
Zn, was used f o r measurement.
C a tio n exchange c a p a c ity determ ined by SCS Labs was done w ith
the amonium a c e t a t e (pH 7 . 0 ) method ( 4 1 ) .
A l l o th e r c a t io n exchanqe
c a p a c ity measurements were done w i t h the sodium a c e t a t e (pH 8 . 2 )
method o f
Bower ( 5 ) .
18
Bulk D e n s ity was done w ith Saran coated peds a t 1 /3 atmosphere
te n s io n f o r SCS samples.
Other samples were a i r d r i e d , coated w ith
l i q u i d S a ra n , and weighed in and out o f w a t e r .
The >2 mm f r a c t i o n
was s epa ra te d a f t e r w eighing to make measurements based on f i n e
earth .
Phosphorus s o r p tio n "isotherm s" were done a ccording to procer
dures o f Fox and Kamprath ( 1 2 ) .
F i f t e e n samples r e p r e s e n tin g e o lia n
and b u r ie d horizons w ith a v a r i e t y o f c o lo rs and te x t u r e s were chosen
f o r t h i s a n a l y s is .
tra tio n s :
Phosphorus as CaHgPO^ w ith the f o l l o w i n g concen­
0 .9 , 9 .0 , 3 2 .0 ,
the 15 samples.
1 0 0 .0 , and 3 2 0 .0 ppm was added to each o f
Values f o r P sorbed by 8 r e p r e s e n t a t i v e samples are
p l o t t e d a g a in s t e q u i l i b r i u m c o n c e n tra tio n s on l o g - l o g graph paper
(F ig .
5 , page 4 2 ) .
Fox and Kamprath p l o t t e d t h e i r s on s e m i-lo g w ith
P-sorbed on th e l i n e a r s c a le ( 1 2 ) .
These "isotherm s" in d ic a t e d t h a t 3 2 .0 ppm P gave a wide range
o f P s o r p tio n v a lu e s .
A 1:10 s o i l t o s o l u t i o n r a t i o was made w ith
each sample and 32 ppm P in a .01 M Cacl s o lu t io n to determ ine a
phosphorus s o r p tio n index s i m i l a r to t h a t o f Bache and W illia m s ( 3 ) .
The r a t i o o f P sorbed t o P added o v er an e q u i l i b r a t i o n pe rio d o f one
week i s converted to a p e rce n ta g e .
phosphorus s o r p tio n in d e x.
This value w i l l
be c a l l e d the
19
A n a ly s is o f Data
An index o f consis te n c e was c re a te d f o r r a t i n g morphological
d a ta .
Adhesive and cohesive fo rc e s g iv e the s o i l a c h a r a c t e r i s t i c
f e e l v a r y in g w it h m o istu re c o n te n t o f the s o i l .
Four d e te rm in a tio n s
a re made r e p r e s e n tin g w et ( w ) , m o ist ( m ) , and dry (d ) c o n d itio n s .
The minimum consis te n c e i s d e fin e d here as a s o i l
t h a t is loose when
m o ist and d ry and is n o n -s tic k y and n o n - p la s t i c when w e t.
th e lo w es t v a lu e f o r th e consis te n c e in d e x o r I .
This is
The h ig h e s t con­
s is te n c e index o f 20 re p re s e n ts the maximum consis te n c e when a s o i l
i s e x tre m e ly f i r m ( m ) , e x tre m e ly hard ( d ) , very s t i c k y (w) and very
p la s tic
(w ).
For e ve ry change in any o f th e fo u r c h a r a c t e r i s t i c s
o f consis te n c e or l e v e l o f consis te n c e w i t h i n t h a t c h a r a c t e r i s t i c ,
the c o n s is te n c e index w i l l
change by I u n i t .
S t r u c t u r a l grade was q u a n t i f i e d as fo llo w s :
I - v ery weak,
2 - weak, 3 - weak t o m o d e rate , 4 - m oderate, 5 - moderate t o s tr o n g ,
6 - s tr o n g , and 7 - v e ry s tro n g .
I n t e r p r e t a t i o n o f X -r a y d i f f r a c t i o n p a tte r n s in c lu d e s an.
e s tim a te o f th e r e l a t i v e abundance o f c r y s t a l l i n e c la y m in e r a ls .
This e s tim a te was based on areas under th e prim ary X -r a y d i f f r a c t i o n
peaks and is u s e fu l o n ly f o r comparisons w i t h i n t h i s t h e s i s .
R e l a t iv e abundance o f amorphous cla y s was based on in d ic e s o f
amorphous c h a r a c te r (T a b le 10) and la c k o f peaks in the d i f f r a c t i o n
p a tte rn .
RESULTS AND DISCUSSION
Survey o f S o il S c i e n t i s t s
This survey suggests t h a t many s o i l s in Western Montana have
s u rfa c e horizons t h a t have p r o p e r t i e s commonly a s s o c ia te d w ith v o l - .
cam"c ash i n f l u e n c e .
Not a l l
r e s u l t o f v o lc a n ic ash a lo n e .
the respondents f e e l
th is
l a y e r is a
The many names given to t h i s l a y e r
r e f l e c t th e q u e s tio n a b le o r i g i n i n c lu d i n g :
s u r f a c e , " " B i r , " and "ashy m a n t le ."
I t w ill
"loess c a p ," "brown
be c a l l e d th e "andic"
l a y e r in t h i s th e s is because t h i s term r e f e r s to p r o p e r t i e s a ss o c iate d
w ith Andosols o r v o lc a n ic ash s o i l s , and does not a t t r i b u t e these
p r o p e r tie s to v o lc a n ic ash a lo n e .
Andic la y e r s are recognized in th e f i e l d by t h e i r c o l o r ,
t e x t u r e , and bulk d e n s i t y .
S ix te e n o f the 22 respondents used brown
to reddish brown c o l o r as an i n d i c a t o r o f ash i n f l u e n c e .
Of these 1 6,
th r e e s a id brown c o l o r alone was not a good i n d i c a t o r o f v o lc a n ic ash
in flu e n c e .
ash.
One s a id brown c o l o r was n o t n e c e s s a r ily from v o lc a n ic
Three respondents s a id w h ite to gray c o lo rs were ass o c iate d w ith
v o lc a n ic ash.
Two f e l t t h a t d a r k e r values and chromas as low as 3 /1
o r 3 /2 were p o s s ib le f o r andic l a y e r s .
Even though brown c o lo r may
come from s e v e ra l pedogenic p rocesses, i t was the c o l o r most o fte n
a s s o c ia te d w ith v o lc a n ic ash i n f l u e n c e .
Fourteen respondents say t e x t u r e . i s
n itio n .
used in andic l a y e r recog­
Ten o f these s a id th e l a y e r has a s i l t loam t e x t u r e i n d i c a t i n g
high s i l t c o n te n t.
Three s a id loam was the t e x t u r e o f ash in flu e n c e d
21
s o il.
One mentioned f i n e sandy loam and another s i l t y c la y loam.
Two r e f e r r e d to lo e s s -1 i k e c h a r a c t e r .
A ll
it
is low.
nine who used b u lk d e n s it y to re co g n ize ash in flu e n c e say
Values o f 0 . 8 to 1 .1 gram s/cubic c e n t im e te r were g iv en .
O ther p r o p e r tie s used to re co g n ize ash i n f lu e n c e were r e l a t e d
to th e way the andic l a y e r f e l t to th e touch.
andic l a y e r had a smeary, soapy f e e l
vey.
Respondents s a id the
i n the western zone o f the s u r ­
S o i ls in th e w estern areas o f in f l u e n c e maybe t h i x o t r o p i c .
One
respondent from the G l a c i e r Park area s a id the l a y e r had a sharp f e e l .
Unweathered b u rie d ash has been found near G l a c i e r Park ( 2 0 ) .
F lu ffy
and f l o u r y when d r y , n o n s tic k y arid n o n p la s t ic when wet were terms
a s s o c ia te d w ith andic l a y e r s .
An. a b ru p t low er t e x t u r a l boundary below the andic l a y e r and
hollow sound were two o t h e r c h a r a c t e r i s t i c s mentioned.
Thickness o f th e andic l a y e r v a r ie d w ith geographic l o c a t i o n .
A 55 to 60
cm maximum th ic kn es s is found i n Northern Idaho and
a d ja c e n t p a r ts o f M i n e r a l , Sanders, and L inc oln Counties in Montana.
The depth averages 30 to 45 cm in th e mountains to th e e a s t o f the
Northern Idaho-Montana b order and may average <50 cm to the south
o f Sandpoin t ,
Idaho.
The m a j o r i t y o f th e mountains from G la c ie r
N a tio n a l Park south to near D i l l o n have a l a y e r t h a t i s 10 to 20 cm
th ic k (F ig .
8 , page 5 0 ) .
22
P hysiographic p o s i t i o n appears r e l a t e d to depth and d i s t r i ­
b u tio n in areas where th e l a y e r is r e l a t i v e l y t h i n .
Ten respondents
a s s o c ia te d th e l a y e r w ith north o r n o r th e a s t aspects w h i le one s aid
i t could be found on south a s p e c ts .
Seven s a id high e l e v a t i o n s are
a s s o c ia te d w ith th e a n d ic l a y e r ; one d is a g re e d .
Two f e l t t h a t
g r e a t e r th ic kn es s o f th e andic la y e r s a t h ig h e r e le v a t i o n s fo llo w e d
a d i r e c t r e l a t i o n s h i p w ith p r e c i p i t a t i o n which als o in c re a se d a t
h ig h e r e l e v a t i o n s .
F o re s t v e g e ta tio n is found w ith andic s o i l s by 11 respondents.
Four s a id i t
could be found under grassy v e g e ta tio n w i t h o u t t r e e s .
One s a id i t was more mixed under grass.
The andic l a y e r s found under
grass were g e n e r a l l y in th e w estern end o f the survey d i s t r i b u t i o n o r
a t high e l e v a t i o n s .
w it h v e g e t a t i o n .
Three s a id they saw o n ly broad o r no r e l a t i o n s h i p
One respondent suggests t h a t the andic l a y e r is
found where snow is deep enough in the w i n t e r to p re v e n t the s o i l from
f r e e z in g in most y e a r s .
Nine respondents saw no r e l a t i o n s h i p between th e andic s u rfa ce
and p a r e n t m a t e r i a l
found below.
Three s a id lim estone a f f e c t e d t h i c k ­
ness o f th e andic l a y e r and r a is e d in e l e v a t i o n th e low er l i m i t o f
its d is trib u tio n .
P e r m e a b il i t y o f th e bu rie d m a t e r ia l was r e l a t e d
by fo u r to th ic kn es s o f th e andic l a y e r .
Coarse permeable s u b s tra ta
23
had t h i c k e r andic la y e r s than les s permeable m a t e r i a l such as com­
pacted t i l l .
The f e r t i l i t y
v a lu e o f th e andic l a y e r was q u e s tio n e d .
s a id the andic l a y e r added to th e f e r t i l i t y .
S ix
S ix oth e rs s a id the
l a y e r had p r o p e r tie s a s s o c ia te d w it h good f e r t i l i t y , bu t d id not men­
t i o n high f e r t i l i t y
d ire c tly .
These p r o p e r t ie s in c lu d e d :
High c a tio n
exchange c a p a c i t y , high w a t e r h o ld in g c a p a c i t y , high n itr o g e n and
phosphorus, and high o rg a n ic m a t t e r .
no more f e r t i l e
v a lu e .
Three s a id th e andic l a y e r is
than o t h e r s o i l s and may even have a low f e r t i l i t y
One reason mentioned was t h a t a t low pH v a lu e s , th e base
s a t u r a t i o n is v ery low in a ndic l a y e r s .
A v a il a b l e w a te r was thought
to be low to o .
O ther p r o p e r t i e s in c lu d e d :
Weak a g g r e g a tio n , high erosion
hazard and s u s c e p t i b i l i t y to severe f i r e
damage.
One thought low
b u lk d e n s it y made the andic l a y e r s u s c e p tib le to compaction.
Taxonomic Grouping o f Amorphous C h a ra c te r
S o ils in t h i s study were ranked (T a b le 6) according to c r i t e r i a
i n Table 5.
Three groups were then formed re p r e s e n tin g dominant,
im p o rta n t and i n s i g n i f i c a n t amorphous c h a r a c te r (T a b le 6 ) .
Group I
in c lu d e d Andept s u b o rd e rs ; Group 2 in c lu d e d Andic and A ndeptic sub­
groups; and Group 3 were s o i l s la c k in g c h a r a c t e r i s t i c s o f amorphous
c la y s used in S o il Taxonomy.
24
Table 5.
C r i t e r i a f o r Ranking and Grouping S trength o f Amorphous
C h a ra c te r.
Index
Group I
Group 2
Bulk d e n s it y o f the f i n e e a r t h ( g / c c )
Exchange c a p a c ity o f the c la y a t pH 8 . 2 (me/lOOg)
1 5 -b a r w a t e r r e t e n t i o n :
measured c la y
Organic Carbon (%)
Cation exchange c a p a c i t y :
1 5 -b a r w a te r r e t e n t i o n
Phosphorus s o r p tio n in d e x * (%)
< 0 .8 5
>150
> 1 .0
> 0 .6
not used
> 85
< 0 . 95
not used
> 0. 8
not used
> I. 5
>75
*An a r b i t r a r y r a t i n g and the only index not used in S o il
Table 6.
S o il
Taxonomy.
Order o f Amorphous C h a ra cte r and Taxonomic R eco g n itio n .
Name
Group #
Rank
Taxonomic Recognition
Buckhouse
Unnamed 3
Unnamed 4
T r u e fis s u r e
I
I
2
3
4
Andepts
Wishard
Felan
Holloway
S pring Emery
S u g a rlo a f I
E lk n e r v -2
Cabinet
Krause
E lk n e r v -1
Unnamed 5
2
5
6
7
8
9
10
11
12
13
14
Andie and Andeptics
S u g a rlo a f 2
H ilg a r d
Holloway v
E lkn e r
Unnamed 2
Unnamed I
3
15
16
17
18
19
20
Non-Andic
25
Three s o i l s
in Group I q u a l i f i e d f o r Andept c l a s s i f i c a t i o n
only i f data were averaged f o r the r e q u ire d 35 cm l a y e r .
I n d iv id u a l
horizons in Unnamed 3 and 4 and T r u e f i s s u r e did not meet c r i t e r i a
i n d i c a t i n g dominance by amorphous cla y s
w a t e r :% c la y r a t i o s o f a l l
B 2 3 ir h o rizo n were not met.
(T a b le 7 ) .
th r e e and most c r i t e r i a
The 1 5 -b a r
in the T r u e f is s u r e
The 78 cm andic l a y e r o f Buckhouse
e a s i l y q u a l i f i e d as an Andept.
Table 7.
S o il
Physical and Chemical
Group I .
Name
Horizon Depth
(cm)
A ll
A12
A13
A14
B 2 1 ir
B 2 2 ir
Cl
Unnamed 3
B21
B22
I IA2
Unnamed 4
B21
B22
T r u e f i ssure B21i r
B 2 2 ir
B 2 3 ir
IIB S lir
Buckhouse
O- 10
10- 23
2 3 - 40
4 0 - 58
5 8- 78
78- 95
95-125
0 - 20
2 0- 55
55- 73
0 - 23
2 3 - 55
0- 13
13- 25
2 5- 40
4 0 - 60
In d ic e s o f Amorphous C h a r a c te r ,
Bulk
CEC
15 Bar Organic
P
Density
(m e ./
W a te r/ Carbon S orption
(g /c c )
IO Ogclay) % c la y
(%)
(%)
—_
0 .7 8
0 .7 9
0 .7 0
0 .7 0
0 .9 0
1 .6 0
— —
— —
—
— —
— —
0 .6 8
0 .7 5
1.29
1 .3 8
292
298
235
249
221
178
149
101
410
37
104
197
349
404
112
178
1 .0
1 .2
1.1
1 .2
1 .0
0 .8
0 .7
0 .8
3 .0
0 .4
0 .8
2.1
1 .9
2 .3
0 .6
0 .7
9 .6
6 .4
5 .4
4 .7
2 .3
0 .7
0 .3
1 .3
1 .4
1 .0
1 .9
1 .8
2 .8
1 .9
0 .3
0 .2
95
98
95
95
94
50
50
98
98
38
98
98
98
100
52
41
Amorphous c h a r a c t e r in most s o i l s o f Group 2 was strong enough
f o r Andept c l a s s i f i c a t i o n .
Only Wishard comes c lo s e to meeting the
26
35 cm thic kn es s r e q u ire d o f the Andie l a y e r o f Andepts (T a b le 8 ) .
Because o f an aquic m o istu re regime Wishard could not be an Andept.
I f th is s o il
lacked a c r y i c te m peratu re regime i t would probably
be an Andaquept ( 4 2 ) .
C ry o c h re p ts .
Most o t h e r s o i l s
in Group 2 would be Andie
The Cabinet s e r i e s would be an A nde ptic C ry o b o ra lf .
The main d i f f e r e n c e between th e amorphous c h a r a c te r o f
Group I and 2 was th e l a r g e r bulk d e n s i t i e s in the Andie l a y e r o f
Group 2 (T a b le 8 ) .
by m a t e r i a l
This i s most l i k e l y an e f f e c t o f contam in ation
from b u rie d horizons a s s o c ia te d w ith t h i n n e r e o l ia n
deposits in Group 2.
M ixing o f
e o lia n
and n o n -e o lia n m a t e r ia ls
increases as th ic k n e s s o f the e o l ia n d e p o s it decreases
(3 2 ).
E o lia n mantles o f Group 3 s o i l s had amorphous c h a r a c te r t h a t
was too weak f o r r e c o g n i t io n .
s o i l was not met (T a b le 9 ) .
h ig h .
At l e a s t one andic c r i t e r i a
f o r each
In most cases bulk d e n s it y was too
The E lk n e r s e r ie s has a CEC o f o n ly 105 me/lOOg c la y and a
low P -s o r p tio n index o f 5 6 , n e i t h e r index being c h a r a c t e r i s t i c o f
s i g n i f i c a n t amorphous c h a r a c t e r .
27
Table 8.
Physical and Chemical
Group 2.
In d ic e s o f Amorphous C h a r a c te r ,
S o il Name
Horizon
Wishard
A ll
0 .6 0
1.2
2 .1
84
249
13.7
A12
0 .8 6
0 .9
2 .5
97
222
7 .0
A13
0 .8 0
0 .8
2 .7
94
209
3 .2
B 2 1 ir
1 .2 5
0 .6
2 .9
63
177
LO
B2
0 .7 1
3 .6
2 .0
98
726
3 .0
IIA 2b
0 .8 8
0 .6
2 .3
53
150
0 .8
B2
0 .8 7
1 .0
1 .8
88
180
2 .4
0 .5
1 .6
25
82
0 .4
Felan
Holloway
I IA21
Bulk
15 BH/ CEC/ P- S orption
CEC
Organic
D e nsity t c la y 15 BW
Index
o f c la y
Carbon
(g /c c )
(me/lOOg)
(%)
(%)
—
S pring Emery B21
0 .9 0
1.9
1 .7
98
329
6 .0
B22
0 .9 0
1 .5
1 .8
98
266
2 .8
0 .9
2 .3
45
212
0 .4
1 .2
1 .4
98
167
1 .9
0 .9
1 .9
56
172
0 .7
1 .6
1 .5
100
240
5 .8
I IA2
S u g a r lo a f I
B21
IIB 2 2
E lk n e r v -2
Cabinet
Krause
B2i r
Unnamed 5
0 .9 3
—
0 .9 7
I IB3
—
0 .3
2 .8
33
86
0 .1
B2i r
—
1 .5
1 .7
100
274
2 .2
IIA 2
—
0 .5
1 .3
47
66
1 .3
0 .7
2 .8
97
194
2 .5
0 .4
2 .0
36
77
0 .8
0 .8
1 .5
97
126
1.9
B2
IIA+B
E lk n e r v-1
—
B2i r
0 .8 7
—
0 .9 1
IIB 3
—
0 .5
1 .5
45
72
0 .1
Al
—
1 .9
1 .5
56
290
7 .0
B21
—
L I
1 .3
69
152
1 .9
B3
— —
L I
1 .3
53
140
1 .3
28
Table 9.
Physical and Chemical
Group 3.
S o il Name
Horizon
S u g a rlo a f 2
B2
H ilg a r d
E lkn e r
Unnamed 2
Unnamed I
Bulk
15 BW/ CEC/ P -S o rp tio n
CEC
Organic
Index
D e nsity % c la y 15 BW
o f c la y
Carbon
(g /c c )
(me/lOOg)
(%)
(%)
1 .1 4
B3
-
B2i r
—
Holloway v ar B2i r
In d ic e s o f Amorphous C h a r a c te r ,
-
1.2 5
0 .9
1 .9
75
168
1 .4
0 .6
2 .1
53
113
0 .5
0 .5
1 .6
97
88
3 .7
0 .7
1 .4
97
95
2 .6
0 .4
2 .1
52
84
0 .3
—
—
56
109
5 .8
I IB3
—
B2
-
B3
—
—
-- --------
30
102
0 .9
B21
—
0 .5
0 .8
69
45
1 .6
IIB 2 2
—
0 .4
1 .5
—
59
1 .0
B2
-
0 .4
1 .8
67
65
2 .0
IIC
——
0 .3
2 .2
— —
56
0 .7
-
-
Amorphous C h a ra c te r In d ic a te d by Clay M ine ralogy
In general th e nine s o i l s w ith X -ra y d i f f r a c t i o n p a tte r n s
i n d i c a t e d very small q u a n t i t i e s o f c r y s t a l l i n e clays in horizons w ith
strong amorphous c h a r a c te r (Appendix 3 ) .
Both non-andic e o lia n
mantles and b u rie d horizons had more c r y s t a l l i n e cla y s (T a b le 1 0).
Weakened amorphous c h a r a c te r in the B 2 3 ir o f T r u e fis s u r e was p a r t i a l l y
e x p la in e d by the presence o f more c r y s t a l l i n e clays than any o v e r la y in g
e o l ia n h o rizo n w ith s tro n g amorphous c h a r a c te r ( F i g .
v a r i e t y o f c la y types i n andic la y e r s
was
3 ).
The l a r g e s t
seen in the C abinet s e r ie s
Fig u re 3.
IIBSZir
X -ra y d i f f r a c t i o n p a tte r n s o f T r u e f i s sure.
Mg-saturated
(Angstroms)
K-saturated 350o/500o
r\>
IIBSlir
30
(T a b le 1 0 ) .
C h l o r i t e , v e r m i c u l i t e , i n t e r s t r a t i Tied c l a y s , i l l i t e ,
p a r t i a l l y hydrated h a l l o y s i t e a n d /o r k a o l i n i t e were a l l
Much l a r g e r q u a n t i t i e s o f a l l
p re s e n t.
those c la y s were found in the buried
a r g i l ! i c horizons below C a b in e t's andic l a y e r .
Most o th e r andic
la y e r s w i t h s tro n g amorphous c h a r a c te r had only v e r m i c u l i t e i f
c r y s t a l l i n e c la y s were p r e s e n t.
S o il
Conservation S e rv ic e d a ta in d ic a t e d t h a t th e andic l a y e r
o f th e Holloway s e r ie s was dominated by amorphous c la y s (T a b le 1 0 ).
Felan was shown to have a l a r g e amount o f amorphous c l a y , but in the
IIA 2 2 h o rizo n (T a b le 1 0 ).
Group 3 s o i l s
had l a r g e r q u a n t i t i e s and g r e a t e r v a r i e t y
o f c r y s t a l l i n e c la y s in e o l ia n m antles than did s o i l s w ith strong
amorphous c h a r a c te r (T a b le 1 0 ).
Table 10.
I n t e r p r e t a t i o n s o f X -r a y D if f r a c t i o n P a tte rn s o f
C r y s t a l l i n e Clays o f Eleven Study S i t e s .
S o il
Horizon
Clay M i n e r a l * Abundance+
Buckhouse
A ll
A12
A13
A14
B 2 1 ir
B 2 2 ir
Cl
C2
Vr o r C l ( I ) , 1 1 ( 1 ) , Am(B)
V r ( I ) , 1 1 ( 1 ) , Am(B)
V r ( I ) , 1 1 ( 1 ) , Am(S)
— —
V r ( 2 ) , 1 1 ( 1 ) , K a ( I ) 3 Am(B)
V r ( 2 ) , 1 1 ( 2 - 3 ) , Am(4)
V r (2 to 3 ) , I n ( 2 ) , 1 1 ( 3 ) , C l ( I )
V r ( 2 ) , I n ( I ) , 11(2 to 3 ) , K a ( I )
31
Table 10 Continued
S o il
Horizon
Clay M i n e r a l * Abundance+
T r u e fis s u r e
B21i r
B 2 2 ir
B23i r
IIB S lir
IIB 3 2 ir
IIB 3 3 ir
V r ( 2 ) , Am(S)
V r ( 2 ) , Am(S)
C l ( I ) , V r ( I ) , I n ( 2 ) , 1 1 ( 2 ) , K a ( I ) , Am(2-3)
V r(2 to 3 ) , I n ( 2 ) , 11(2 to 3)
C l ( I ) , V r ( 3 ) , I n ( 2 to 3 ) , 1 1 ( 3 ) , Ka(2)
V r ( 2 ) , I n ( 2 ) , 1 1 (2 ) Hl or K a ( I )
Cabinet
B2
IIA 2
I IB2t
C l ( I to 2 ) ,
V r ( I to 2 ) , I n ( 2 ) , 1 1 ( 2 ) ,
Kaor Hl ( I to 2 ) , Am(S)
C l ( 2 ) , V r ( 3 ) , I n ( 2 to 3 ) , 11(3 to 4 ) , Ka(2)
Cl (2 to 3 ) , V r ( 4 ) , I n ( 3 ) , 1 1 ( 4 ) , K a ( I )
Krause
B21
I IA+B
V r(I),
C l( 2 ) ,
S u g a rlo a f I
B2
IIB 3
V r ( I ) , Am(S)
C l(3 ), V r (2 ), In (2 ),
B 2 2 ir
I IA2
V r ( I ) , Am(S)
V r ( l to 2 ) , I n ( I ) ,
H ilg a r d
B2
V r(2 to 3 ) ,
S u g a rlo a f 2
B21
B3
C l ( 2 ) , V r ( 2 ) , I n ( 2 ) , I l ( I ) , Am(l to 2)
C l (2 to 3 ) , V r ( 2 ) , I n ( 2 ) , 1 1(1)
E lkn e r
Al
B2
B31
V r ( 2 ) , I n ( l to 2 ) ,
V r (2 to 3 ) , I n ( 2 ) ,
V r ( 2 ) , I n ( 2 to 3 ) ,
3 ) , Am(I)
M t ( I ) , V r ( I ) , 11(2
M t ( 3 ) , 11(2 to 3)
S pring Emery
B32
Cl
Holloway#
B2
IIA 2 1
IIA 2 2
IIC l
I n ( 2 ) , 1 1 ( 1 ) , Am(4-5)
V r ( 2 ) , I n ( 2 ) , Ka(2)
—
Cl ( 4 ) M i( 4 )
H l(I),
I n ( 2 to 3 ) ,
Am(S), C l ( I ) , M i ( I )
——
1 1 (2 ) Ka(S)
1 1(2),
K a ( I ) , Am(2)
K a ( S ) , Am(I)
1 1 ( 1 ) , K a ( I ) , Am(4)
1 1 ( 2 ) , H l ( 2 ) , K a ( 2 ) , Am(I)
11(2 to 3 ) , Ka o r Hl (2 to
to 3 ) , H l ( I ) ,
32
Table 10 Continued
S o il
Horizon
F e !an#
A2
B2
IIA 2 1
I IA22
Clay M i n e r a l * Abundance+
M i(4 ) C l(2 )
V r ( 3 ) , M i( 3 ) ,
K a (2 ), M t ( I)
Am(6)
*Mi = m ica, Cl = c h l o r i t e , Vr = v e r m i c u l i t e , Ka = K a o l i n i t e ,
Mt = montmoriI I o n i t e , Am = amorphous, Hl = h a l l o y s i t e ,
In = I n t e r s t r a t i t i e d , I l = I l l i t e .
#SCS Lab d e te r m in a tio n
+1 = t r a c e , 2 = s m a l l , 3 = m oderate, 4 = abundant, 5 = dominant,
6 =. indeterm ined
M orphological
In d ic e s o f Amorphous Clays
Strong amorphous c h a r a c te r was a ss o c iate d w ith th e fo llo w in g
m orphological c h a r a c t e r i s t i c s :
1)
high s i l t c o n te n t, u s u a l l y 60% o r more but as low as 40%;
2)
b r i g h t chroma, u s u a lly fo u r o r more f o r Andept suborder
and th r e e o r more f o r Andie and A ndeptic subgroups;
3)
weak c o n s is te n c e , u s u a lly s o f t , f r i a b l e , n o n - s t i c k y ,
n o n -p la s tic ;
4)
weak a g g r e g a tio n , i n d i c a t e d by weak s t r u c t u r a l
grade.
F o re st s o i l s in Western Montana w ith these fo u r m orphological
c h a r a c t e r i s t i c s are p robably dominated by amorphous c l a y .
Accuracy
o f these in d ic e s decreases as thic k n e s s o f the andic l a y e r decreases.
33
S o ils w ith t h i n andic la y e r s may need la b data to determ ine medial
d e s ig n a tio n .
In Montana, few s o i l s had enough glass to make c l a s s i ­
f i c a t i o n based on glass c o n te n t l i k e l y .
Lab data is s t i l l
necessary
to determ ine i f enough glass is p re s e n t f o r Andept suborder o r ashy
f a m i l y d e s ig n a tio n s .
E x c e p tio n s . to the m orphological
in d ic e s o f s tro n g amorphous
c h a r a c t e r were found in th e Buckhouse a n d .Wishard s e r i e s .
s o i l s had few o f th e m orphological
These
c h a r a c t e r i s t i c s common to other,
a ndic s o i l s w ith strong amorphous c h a r a c t e r .
form ing f a c t o r s may e x p l a i n these e x c e p tio n s .
A d i f f e r e n c e in s o i l
G ra s s -1 ik e v e g e ta tio n .
o f Buckhouse and Wishard may r e s u l t i n s tr o n g e r s t r u c t u r e due to
r o o t p e n e t r a t io n and th e s t a b i l i z i n g e f f e c t o f humus.
Both o f
these s o i l s have h ig h e r Ca++ contents than any o th e r andic l a y e r so
f l o c c u l a t i o n should be g r e a t e r .
I n d i v i d u a l m orphological c h a r a c t e r i s t i c s were not useful f o r
i n d i c a t i n g s tr e n g th o f amorphous c h a r a c t e r .
B r ig h t chromas were
found in th e Holloway v a r i a n t o f Group 3 , which had weak amorphous
c h a r a c te r (T a b le 13, page 3 7 ) .
S i l t c o n te n t in th e a n d ic la y e r s o f
H ilg a r d and Unnamed I was 58% and 56% r e s p e c t i v e l y (T a b le 1 3 ).
Both
were m o d e rately high s i l t contents but these s o i ls had weak amorphous
ch ara c te r.
The andic l a y e r o f C a b in et had only 38% s i l t but strong ■
amorphous c h a r a c t e r .
High sand contents were not from contam ination
34
by the l a c u s t r i n e s i l t s
from below but were iron, and manganese
nodules which formed in pla ce ( N i ml os. Unpublished D a ta ).
The e f f e c t s o f contam in atio n o f the andic l a y e r w ith none o l ia n m a t e r i a l could be seen in some m orphological in d ic e s o f
amorphous c h a r a c te r l i s t e d in Tables 11, 12 and 13.
General contami
n a tio n o f th e whole andic l a y e r was more e v id e n t in the t h i n n e r
e o l ia n d e p o s its o f Group 2 and 3.
Tree throw may be an im p o rta n t
f a c t o r in m ixing s u r fa c e horizons o f f o r e s t s o i ls
(2 2 ).
S u g a rld a f 2
was from a s i m i l a r s i t e as S u g a rlo a f I bu t n e a re r th e r id g e c r e s t
.
where chances o f e ro s io n and t r e e throw may have been g r e a t e r .
S u g a rlo a f I had more s i l t and b r i g h t e r chromas than S u g a rlo a f 2 and
a ls o s tr o n g e r amorphous c h a r a c te r (Ta b le s 12 and 1 3 ).
E lk n e r v l
'
and v2 were als o found v e ry clo se to g e th e r in the landscape but
m icro r e l i e f a t th e E lk n e r v2 s i t e c re a te d a w e t t e r s i t e w ith a
t h i c k e r v e g e t a t i v e co ve r.
v e g e ta tio n was t h i c k e r .
Erosion was probably not as g r e a t where
E lk n e r v2 had l a r g e r s i l t c o n te n t showing
less contam in atio n and r e s u l t e d in s tr o n g e r amorphous c h a r a c te r
(T a b le 1 2 ) .
.
The m orphological c h a r a c t e r i s t i c s ass o c iate d w it h amorphous
c h a r a c te r a re not n e c e s s a r i l y caused by amorphous c la y s o r v o lc a n ic
ash.
O ther pedogenic processes can cause these same f e a t u r e s .
Fungal hyphae in New England Brown P odzolics c re a te d s o i l s w ith
little
s t r u c t u r e , a f r i a b l e c o nsistence and a low b u lk d e n s it y ( 2 3 ) .
35
B r ig h t chromes are found in s o i l s where the p o d z o liz a t io n process
is o c c u r r in g and are many times confused w ith andic la y e r s
(4 3 ).
I t is probably more im p o rta n t to a s o i l mapper to be a b le to recog­
n iz e dominance o f amorphous c la y s using morphological
in d ic e s than
to know the pedogenetic o r i g i n o f those in d ic e s .
Table 11.
S o il
Name
Buckhouse
Unnamed 3
Unnamed 4
T ru e fis s u re
M orphological
Group I .
Rank
I
2
3
4
Data Associated w ith Amorphous C h a r a c te r ,
H o r i zon
T h ic k ­
ness
(cm)
Consis­
tence
Index
S tr u c ­
tu ra l
Grade
S ilt
(%)
A ll
10
4
6
49
2
2
A12
13
4
6
48
2
2
A13
18
4
6
51
2
2
A14
18
4
6
52
2
2
B 2 1 ir
20
4
2
54
4
4
B 2 2 ir
18
4
2
50
4
4
Cl
30
3
-
59
3
3
B21
20
3
2
62
4
5
B22
35
3
2
75
6
5
B21
23
3
3
69
4
6
B22
33
3
3
77
4
6
B21i r
13
3
2
70
4
4
B 2 2 ir
13
3
2
67
4
4
B 2 3 ir
15
5
2
55
4
4
IIB S lir
20
4
2
47
6
6
Chroma
M oist Dry
36
T able 12.
S o il
M orphological
Group 2.
Name
Wishard
Felan
Holloway
S pring Emery
S u g a rlo a f I
E lkn e r v -2
Cabinet
Krause
E lkn e r v-1
Unnamed 5
Rank
5
6
7
8
9
10
11
12
13
14
Data A ssociated w ith Amorphous C h a ra c te r,
Horizon
T h ic k ­
ness
(cm)
Consis­
tence
Index
S tru c ­
tu ra l
Grade
S ilt
(%)
Chroma
M oist Dry
A ll
5
3
2
66
2
-
A12
13
5
6
64
2
4
A13
13
5
4
67
4
3
B 2 ir
20
7
4
65
4
-
82
13
3
-
64
6
5
I IA21b
18
7
-
58
3
2
82
20
3
I
63
3
4
I IA21
55
8
-
39
3
2
821
10
3
-
55
3
4
822
13
5
2
51
4
3
IIA 2
15
3
-
23
3
3
821
18
5
2
54
3
3
IIB 2 2
20
9
-
25
3
2
B 2 ir
18
4
I
62
3
4
II B 3
25
9
-
36
3
2
B 2 ir
25
2
2
38
5
4
II A 2
13
8
6
53
3
2
82
23
4
2
29
4
4
IIA&B
35
6
2
35
4
4
B 2 ir
18
3
2
32
4
4
1 183
10
3
-
13
3
3
Al
5
-
4
61
4
2
821
8
-
2
65
4
3
831
10
-
2
69
3
3
37
Table 13.
S o il Name
S u g a rlo a f 2
M orphological
Group 3.
Rank
15
Data Associated w ith Amorphous C h a ra c te r,
Horizon
T h ic k ­
ness
(cm)
Consis­
tence
Index
S tru c ­
tu ra l
Grade
S ilt
(%)
B2
20
5
2
30
2
2
B3
15
9
-
54
2
2
Chroma
M oist Dry
H ilg a r d
16
B 2 ir
20
7
-
58
3
3
Holloway v
17
B2i r
20
5
2
33
5
5
I IB31
28
3
-
23
4
2
B2
13
4
5
23
3
2
B31
15
3
-
12
3
2
B2
15
5
2
48
2
2
IIC l
58
5
2
39
2
3
B21
15
7
4
56
3
3
I IB22
58
7
4
39
4
3
18
E l kner
Unnamed 2
Unnamed I
19
20
Amorphous C h a ra cte r and Chemical P r o p e r tie s
Mean chemical data was t a b u la t e d by taxonomic group f o r andic
horizons and s u b ja c e n t horizons w i t h i n 25 cm (T a b le 1 4 ).
Chemical
data was recorded by horizon in Appendix 3 , Table 19.
Andic la y e r s from Group I and 2 had on the average l a r g e r
c a t io n exchange c a p a c i t i e s
(CEC), more a v a i l a b l e phosphorus, t o t a l
n i t r o g e n , exchangeable potassium , and e x t r a c t a b l e copper than andic
la y e r s o f Group 3 (T a b le 1 4 ) .
Group I and 2 s o i l s w ith strong
amorphous c h a r a c te r a ls o have low er bulk d e n s i t ie s than non-andic
Table 14. Mean Chemical Properties of Andie (a) and Subjacent (b) horizons within 25 cm.
E x tr a c ta b le Minor Elements
Degree of
Fe
Mn
Amorphous
Character
Cu
Zn
E xtra c ta b le Cations
Ca
P Dm
Mg
Na
K
me/1 00g
A v a ila b le
Total
P
N
ppm
%
pH
CEC (7)
CEC ( 8 . 2 )
me/lOOg
High
I
a
28
38
2 .8
1 .0
3 .0
.6
.14
.62
171
.225
5.8
16.2
19.2
b
23
16
4.1
1.7
1.0
.4
.09
.24
22
.024
5 .5
7.2
6.7
a
90
75
1.7
.7
8.5
1.0
.34
.59
320
.105
5.7
27.4
27.1
b
38
11
1.1
.4
5.7
1.2
.28
.20
30
.038
5.3
11.6
11.4
a
79
149
.9
.9
6.6
1.2
.36
.51
140
.063
5.7
15.5
b
36
77
1.0
.2
11 .6
1.3
.03
.26
49
.038
6.1
11.6
Med
2
Low
3
39
s o il m a te ria l
(T a b le 1 7, page 4 7 ) .
Because o f t h i s ,
v alu e s .e x p res s ed
on a volume basis are no t as la r g e f o r andic la y e r s as i t
expressed on a w e ig h t b a s is .
appears when
The CEC o f the T r u e f is s u r e 0 to 25 cm
andic l a y e r is not s i g n i f i c a n t l y l a r g e r than non andic m a t e r ia l
the 25 to 37 cm zone, when expressed on a w eig h t basis
(F ig .
in
4 ).
T e x tu re o f T r u e fis s u r e s a ndic and b u rie d la y e r s a re s i m i l a r
when compared to the c o n t r a s t between andic and b u rie d la y e r s o f
E lk n e r v -2 (T a b le 1 5 ) .
Expression o f CEC f o r E lk n e r v -2 on a volume
basis shows a much s t r o n g e r c o n t r a s t between CEC o f andic and buried
la y e r s than does th e T r u e f i s s u r e data (T a b le 1 5 ).
Table 15.
E f f e c t s o f T e x tu re on C o n tr a s t Between Andic and Buried
S o il.
Sand
(%)
S ilt
(%)
andic
26
68
6
2 0 .3
14.4
b u rie d
42
51
7
9 .7
12.6
d iffe re n c e
16
17
I
10.6
1 .8
andi c
21
62
17
4 1 .7
35.0
b u r ie d
58
36
7
5 .7
7 .5
d iffe re n c e
37
26
10
3 6 .0
■ 2 7 .5
Clay
(%)
CEC by w t .
(me/100 g)
CEC by volume
(me/100 c c )
T r u e fis s u r e
E lk n e r v -2
..
40
Weight
CEC (me/lOOg)
10
20
30
40
50
60
Depth
(cm)
Volume
CEC (me/100 cc)
20
30
40
Depth
(cm)
F ig u re 4.
Comparison o f CEC on a w e ig h t and volume basis f o r
T r u e f i s s u re .
41
Mean c a t io n exchange c a p a c ity f o r Group I andie la y e r s was
3 m e/IOOg l a r g e r when measured a t pH 8 . 2 than when measured a t pH
7 .0 (T a b le 1 4 ) .
Only the Andie l a y e r o f Wishard showed any sign o f
pH dependent charge f o r th e o t h e r groups (Appendix 3 ) .
pH f o r a n d ic la y e r s i s 5 . 8 ; t h e r e f o r e ,
The average
CEC is expected to be lower
under f i e l d pH than a t th e pH 7 .0 o r 8 . 2 t h a t CEC was measured a t
in th e l a b .
Because o f the probable pH dependent charge, lim in g to
r a i s e th e pH may be an im p o rta n t management to o l
in the f u t u r e f o r
i n c r e a s in g CEC.
Group 2 andic l a y e r s had the g r e a t e s t mean a v a i l a b l e
phosphorus (B ray P) c o n te n t (T a b le 1 4 ) .
V a r i a b i l i t y was high among
horizons in t h i s group ranging from 26 to 1200 ppm (Appendix 3 ) .
Mean Bray P f o r andic la y e r s o f Group I and 3 were n e a r l y the same
(T a b le 1 4 ) .
On a volume basis Group I andic la y e r s would have less
Bray P than Group 3.
A l l b u rie d l a y e r s had less Bray P than andics.
Phosphorus s o r p tio n was g e n e r a l l y h ig h e r in s u r fa c e horizons
bu t no t j u s t in horizons w ith s tro n g amorphous c h a r a c te r .
B21 has low amorphous c h a r a c t e r b u t high P -s o rp tio n
16).
Burning o f t h i s . s o i l may have decreased i t s
(F ig .
The E lkner
5 and Table
amorphous. c h a r a c te r .
Although P -s o r p tio n may b e . >95% in most andic l a y e r s ,
it
(Bray P)
appears t o be h i g h l y a v a i l a b l e a t l e a s t i n the Group 2 andic la y e rs
(T a b le 1 4 ) .
added P.
P lan ts on Group I a ndic l a y e r s may show a response to
42
O
O
K
w
C
O
■H
O
to
U
C
0>
§
O
•H
U
\\
.
\
r—
<
•H
g-
I
OOO
o
o
I
o
(8/S it) p a q j o s j
Figure 5.
Phosphorus S o rp tio n "Isotherm s"
43
T a b le 16.
S o il Samples used f o r Phosphorus S o rp tio n " Is o t h e r m s ; "
Number
S o il Name
Horizon
Depth
I
E l kner
B21
0- 7
2
Wishard+
A12
2- 7
3
Buckhouse*
B 2 1 ir
23-31
4
W is h a rd *
B 2 1 ir
12-20
5
Wishard
IIC l
46-62
6
E lk n e r
IIB 3
7-11
7
C abinet
IIA 2
11-16
8
S u g a r lo a f 2
B3
*Andic horizons
8 -15
.
T o ta l n itr o g e n was g r e a t e s t in andic la y e r s o f Group I ;
Group 2 had more than Group 3 (T a b le 1 4 ) .
Mean t o t a l
and
n itr o g e n is
a p p a r e n tly high because o f th e high o rg a n ic m a tte r c onte nts in Al
horizons o f Buckhouse and Wishard (Appendix 3 ) .
o f Group I had a mean t o t a l
Brown andic la y e r s
n itr o g e n o f .065 ppm; not much d i f f e r e n t
from .059 ppm f o r brown a ndic l a y e r s o f Group 2.
Group 3 was not
much low er a t .063 ppm.
Exchangeable bases (Ca+-+, Mg*-+, Na+, and K+) tended to be more
abundant i n upper horizons o f s o i l s w i t h strong amorphous c h a r a c te r
(T a b le 1 4 ) .
Group I and 2 s o i l s had more bases and h ig h e r pHs than
th e horizons im m ed ia te ly below (T a b le 1 4 ) .
The s l i g h t decrease in
pH below the a ndic l a y e r in s te a d o f th e usual in c r e a s in g pH w ith
44
depth may i n d i c a t e the e f f e c t s o f n u t r i e n t c y c lin g in t h i s
la y e r.
The lowered pH below th e andic la y e r s o f Group I and 2 i s a remnant
o f a h i g h ly leached h o riz o n o f b u rie d f o r e s t s o i l s .
A2 horizons s t i l l
Since the b u rie d
have low pH v a lu e s , t h i s in d ic a te d th e y are . s t i l l
w i t h i n th e zone o f e l u v i a t i o n .
DTPA e x t r a c t a b l e i r o n and manganese were l e a s t abundant in
andic la y e r s w i t h s tr o n g e s t amorphous c h a r a c te r (T a b le 1 4 ) .
g e n e r a l , these elements were more abundant near the s u r fa c e .
.
In
No
tre n d was seen f o r copper or z i n c .
Amorphous C h a ra c te r and Physical P r o p e r t ie s
Water h o ld in g c a p a c ity expressed on a volume ba sis was less
than when expressed on a w e ig h t b a s is f o r s o i l s w it h stro n g amorphous
c h a r a c t e r f o r th e same reasons th e r e i s a d i f f e r e n c e f o r chemical
d a ta .
The d i f f e r e n c e between andic and b u rie d la y e r s was s t i l l
s i g n i f i c a n t when a l a r g e t e x t u r a l d i f f e r e n c e e x is te d between andic
and b u r ie d .
In T r u e f i s s u r e , sand c o n te n t o f the a ndic l a y e r is
12% d i f f e r e n t from th e b u r ie d (T a b le 1 5 ) .
The d i f f e r e n c e between
andic and b u rie d sand c o n te n t o f E lk n e r v -2 is 37%.
Water holding
c a p a c ity o f th e andic l a y e r o f E lk n e r v -2 is s i g n i f i c a n t l y l a r g e r
than th e coarse te x tu r e d b u rie d l a y e r ( F i g .
6 ).
T r u e f i s s u r e did not
show as g r e a t a change in w a te r h o ld in g c a p a c ity ( F i g .
7 ).
Andic
la y e r s over g r a n i t i c b u r ie d m a t e r i a l should be more im p o r ta n t to
Water R e te n tio n (% by w e ig h t)
Weight Basis
0
10
20
30
40
50
60
70
1 /3 BW
Depth
(cm)
Volume Basis
Water R e te n tio n (% by volume)
Depth
(cm)
Fig u re 6.
Comparison o f w a te r h o ld in g c a p a c i t i e s on a w eig h t and
volume basis f o r E lk n e r v - 2 .
46
Weight Basis
Water R e te n tio n (%)
10
Volume Basis
30
40
Water R e te n tio n (%)
10
Figure 7.
20
20
30
40
Comparison o f w a te r h o ld in g c a p a c ity on a w e ig h t and
volume basis f o r T r u e f i s s u r e .
47
p l a n t growth than a ndic la y e r s over f i n e r te x tu r e d rocks such as
the a r g i l l i t e s
o f T r u e f i ssure.
Andic la y e r s w ith stro n g amorphous c h a r a c te r g e n e r a l l y had
les s c la y and more s i l t than others (T a b le 1 7 ).
Layers w ith the
s tr o n g e s t amorphous c h a r a c t e r were u s u a l l y t h i c k e r so would have
les s contam in atio n due to m ixing than t h i n n e r l a y e r s .
They would
r e t a i n t h e i r e o l ia n c h a r a c te r .
Bulk d e n s it y i n Group I was le s s than Group 2 and Group 3
m ostly by d e f i n i t i o n o f Andepts.
T h in n e r andic la y e r s o f Group 2
would be s u s c e p tib le to m ixing and c o ntam in ation by high bulk
d e n s it y m a t e r i a l
from below which could have a h ig h e r bulk d e n s ity
than e o l i a n m a t e r i a l s .
Table 17.
Degree o f
Amorphous
C h a ra cte r
Mean Physical P r o p e r t ie s o f Andic ( a ) and Subjacent (b)
Horizons W ith in 25 cm.
Mechanical A n a ly s is
Sand
S ilt
Clay
{ %)
Bulk
D e n s ity
(g /c c )
Water Holding Capacity
1 /3 Bar
15 Bar
(% by w t . )
High
(C r.I)
a
28
.61
8
0 .7 3 *
38.3
1 0.9
b
46
48
5
1.3 2
2 0 .5
2 .4
Medium
a
33
56
12
0 .8 1
5 5 .6
1 7.0
b
44
43
12
1 .1 8
2 7 .5
6 .4
a
46 '
39
15
1 .2 0
■ .2 8 .2
1 1.4
b
58
30
12
”—
2 3 .5
4 .3
(G r.2)
Low
( G r. 3 )
*N o t i n c lu d i n g T r u e f i s s u r e B 2 3 ir
48
D i s t r i b u t i o n o f Amorphous C h a ra cte r in Montana
Andepts o f t h i s study were found in th r e e c o u n tie s o f Montana
which b order Idaho; L in c o ln , Sanders and M ineral
(F ig .
2 ).
This
corresponded to areas mentioned in the survey where the t h i c k e s t
d e p o s its were found (Appendix I ) .
I t a ls o corresponded to the
n o rth e rn p o r t io n o f th e a rea in Montana where the N a tio n a l S o ils
A tla s recognized Andepts ( 3 8 ) .
W ith in t h i s area a re th r e e s o i l s
from Group 2 which had some unique p r o p e r t i e s .
Wishard had the
s tr o n g e s t amorphous c h a r a c te r o f Group 2 and came c lo s e to q u a l i f y i n g
as an Andept.
C a b in et has one o f the lo w es t e le v a t io n s o f any s i t e
w ith s tro n g amorphous c h a r a c t e r .
r e s t r i c t e d to h ig h e r e l e v a t i o n s
Most s o i l s o f Group 2 were
(>1097 m e ters)
(T a b le 3 ) .
Unnamed 5
appeared t o have formed i n a llu v iu m r a t h e r than e o l i a n p a re n t
m a te ria ls .
re g io n a l
mate.
It s till
had f a i r l y stro n g amorphous c h a r a c t e r .
A
d i s t r i b u t i o n o f amorphous c h a r a c te r appears r e l a t e d to c l i ­
The. Andepts a re found where p r e c i p i t a t i o n is hig h .
Al I o th e r s o i l s from Group 2 were found i n c o u n tie s which
b order Missoula County ( F i g .
2 ).
A e ria l
d is trib u tio n
in t h i s region
was l i m i t e d to n o r th e a s t aspects and h ig h e r e le v a t io n s according
to th e survey and s i t e lo c a tio n s o f Group 2 s o i l s .
E lk n e r v -1 and
v -2 and S u g a r lo a f I and 2 were c lo s e to g e th e r but showed the
l o c a l i z e d s tre n g th s o f amorphous c h a r a c te r in t h e i r r e g io n .
49
S o ils from Group 3 were found in the mountains to the south
and e a s t o f th e c o u n tie s in which Groups I and 2 were found.
Three zones were d e l in e a t e d from the lo c a tio n s o f s i t e s
w i t h i n each group, to re p r e s e n t regions where the th r e e degrees
o f amorphous c h a r a c t e r may be expected ( F i g . 8 ) .
The d i s t r i b u t i o n o f e o l i a n depo s its w ith strong amorphous
c h a r a c t e r had a s trong a s s o c ia tio n w ith an oro g ra p h ic e f f e c t on the.
p r e v a i l i n g winds which c a r r i e d a s h , loess and p r e c i p i t a t i o n .
This
o ro g ra p h ic e f f e c t is exaggerated by the p r o t e c t i o n from e rosion
coming from t h i c k e r v e g e ta tio n where p r e c i p i t a t i o n is g r e a t e r .
The
Idaho B a t h o l i t h appears to be an e f f e c t i v e tu n n e lin g de vic e which
c o n ce n tra te d Cascade Range v o lc a n ic a sh,
Palouse
loess and wet
m a ritim e a i r i n t o the n orthw e s tern p a r t o f Montana.
Another c l i m a t i c f a c t o r in the genesis o f ash enriched loess
i s the m oderating e f f e c t o f deep snow.
One respondent i n th e survey
suggested t h a t a ndic l a y e r s were found where the snow was deep enough
i n most y ea rs to p re v e n t th e s o i l
from f r e e z i n g
(Appendix I ) .
F re ezin g and thawing c yc les would be g r e a t e r above and below t h i s
zone and may tend to in c re a s e p h y s ic a l w ea th e rin g and decrease
chemical w e a th e rin g .
C lim a te may be as im p o rta n t in th e genesis o f andic la y e rs
as a r e p a r e n t m a t e r i a l s such as v o lc a n ic ash.
50
Zone
1
2
3
Figure 8.
Amorphous
Character
Thickness
cm.
Distribution
strong
moderate
weak
30-45
15-20
10-20
general
high elevation
spotty
Estim ated d i s t r i b u t i o n o f s o i l s w ith amorphous c h a r a c te r
in Montana.
SUMMARY
A survey o f s o i l s c i e n t i s t s
in Montana and p a rts o f Idaho
re g a rd in g t h e i r knowledge o f v o lc a n ic ash in flu e n c e d s o i l s in d ic a te d
th e r e was disagreem ent as to th e genesis and p r o p e r tie s o f a l a y e r o f
s o il
a s s o c ia te d w ith v o lc a n ic ash i n f l u e n c e .
Twenty s o i l s were c o l ­
le c t e d from Western Montana having ap p are n t e o lia n i n f l u e n c e and
probable v o lc a n ic ash i n f l u e n c e .
Chemical and p h y sic a l a n a ly s is were completed and used to r a t e
the s o i l s
in o rd e r o f amorphous c h a r a c t e r .
Three groups were formed .
r e p r e s e n t i n g . s o i l s w ith s tr o n g , moderate and weak v o lc a n ic ash
i n f l u e n c e as i n d i c a t e d by th e s tr e n g th o f amorphous c h a r a c te r .
Group I were c l a s s i f i e d as Andept s u borders; Group 2 as Andie and
Andeptic subgroups, and Group 3 were no t recognized a t e i t h e r o f
these two l e v e l s o f S o il Taxonomy.
S o ils w ith s trong amorphous c h a r a c t e r tended to have the
f o l l o w i n g m orphological c h a r a c t e r i s t i c s :
1)
low b u lk d e n s ity
2)
high s i l t c o n te n t, u s u a lly >60%,
3)
weak c o n s is te n c e , u s u a lly s o f t , f r i a b l e , non s t i c k y ,
non p l a s t i c ,
4)
high chroma, u s u a lly fo u r o r more f o r Andept suborders
and th r e e o r more f o r Andie and Andeptic subgroups,
5)
weak a g g r e g a tio n , a weak s t r u c t u r a l
grade.
52
Andie la y e r s appear to be f e r t i l e when CEC, f e r t i l i z e r e l e >
'
ments and w a te r h o ld in g c a p a c ity a re expressed on a w e ig h t b a s is .
Because o f low bulk d e n s it y in s o i l s w it h stro n g amorphous c h a r a c t e r ,
expression o f these d a ta on a volume basis, shows l i t t l e
d iffe re n c e
between andic and non andic s o i l s o f s i m i l a r t e x t u r e .
In general amorphous c h a r a c t e r appears s tr o n g e s t in L in c o ln ,
Sanders, and M in e ra l c ountie s and weakens to the south and e a s t.
CONCLUSION
S o ils w ith strong amorphous c h a r a c te r are g e n e r a l l y found
northw est o f M is s o u la , where the c lim a t e is wet and the loess
a p p a r e n tly r i c h in v o lc a n ic ash.
East and south o f Missoula mis-
c l a s s i f i c a t i o n o f s o i l s w ith e o l ia n s u rfa c e la y e r s could be prevented
i f the m orphological
in d ic e s o f amorphous c h a r a c te r presented in
t h i s paper are used.
Very few andic la y e r s in Montana appear to
have enough v o lc a n ic glass to make p e tr o g r a p h ic exam ination necessary
fo r c la s s ific a tio n .
Andic la y e r s have c h a r a c t e r i s t i c s which make them r e l a t i v e l y
fe rtile
compared w it h la y e r s t h a t a re coarse t e x t u r e d , f i n e te x tu r e d
o r compacted.
The andic l a y e r is expected to be the m ajor source
o f n u t r i e n t s and w a te r when i t occurs over coarse te x t u r e d g r a n i t i c
m a te ria ls .
Poor r o o t p e n e t r a t io n in c la y e y or compacted s ubso ils
could make andic la y e r s the main source o f a i r , n u t r i e n t s
w ater.
and
On a volume b a s i s , n u t r i e n t and w a t e r holding c a p a c ity may
be no g r e a t e r in andic la y e r s than comparably t e x tu r e d s o i l s .
The
pH dependent c a t io n exchange c a p a c ity is p o t e n t i a l l y v a l u a b l e .
Liming to r a i s e th e pH could s i g n i f i c a n t l y in c re a s e c a t io n exchange
c a p a c ity .
APPENDICES
APPENDIX I
Responses to th e Survey on V o lc a n ic Ash In flu e n c e d
S o ils in Montana and P arts o f Idaho
October 1975
#1
HAVE YOU SEEN VOLCANIC ASH INFLUENCED SOILS?
IF SO, WHERE?
(I)
Near Condon, Missoula County and Rye Creek, R a v a l l i
County.
(3 )
The v o lc a n ic ash recognized on th e B i t t e r r o o t N a tio n a l F orest
is E o l i an.
In a d d i t i o n , th e r e a r e areas o f r e s id u a l s o i l s
d eveloping from weathered v o lc a n ic rock ty p e s.
(4 )
I have seen loess in flu e n c e d s o i l s t h a t may c o n ta in ( v o l c a n i c ) ,
ash.
These areas o f d e p o s itio n a re the high e l e v a t i o n (2580
m +) r i d g e s , c ir q u e basins and n o rth e rn exposures o f windswept
rid g e s .
The loess i n f l u e n c e on th e north e rn exposures v a r ie s
from 2100 m to 2 ,7 0 0 m.
Locations in c lu d e :
Madison Range,
G a l l a t i n Range, Absaroka Range.
(5 )
A v o lc a n ic ash m antle e x i s t s from Le w is ton, Idaho th ic k e n in g
towards the Canadian border in th e m ountains, in c lu d in g ash
over loess e a s t o f Moscow in th e Palouse.
Thins to e a s t and
south.
(6 )
In s u rfa c e s o i l s in G l a c i e r County and as b u rie d ash in G l a c i e r ,
Toole, Lewis & C l a r k , J e f f e r s o n , Broadw ater, Cascade and Madison
coun tie s and in w estern A l b e r t a , Canada.
In G l a c i e r County the
ash l a y e r can be found in wet areas such as pot holes or wet
t e r r a c e s l i k e along the M i l k R iv e r and Cut Bank Creek.
(7 )
Ash caps a re common in th e mountains e a s t o f th e C o n tin e n ta l
D iv id e from G l a c i e r Park south to Roger's Pass.
They are
p a r t i c u l a r l y e x te n s iv e a t h ig h e r e le v a t io n s in th e Bob M arshall
and Scapegoat W ilderness p o r tio n s o f t h i s a r e a .
Remnants o f
f o r m e r ly more e x t e n s iv e caps a re found in the L i t t l e B e l t ,
C ra zy, and Big Snowy Mountains.
(8 )
Western Montana.
(9 )
Deepest i n f l u e n c e on th e Kootenai N a tio n a l F o re s t and l e s s . i n
th e S t. Regis Area o f the Lolo N a tio n a l F o re s t.
56
(1 0 )
Yes, in Northern Idaho.
■'
(1 1 )
E a r ly work done i n the f i e l d and l a b o r a t o r y study o f v o lc a n ic ash in flu e n c e d s o i l s was o f th e Holloway and Buckhouse
(Horsehead) s e r ie s in M issoula County and o f th e T r u e f i s s u r e ,
Craddock and Wishard s e r ie s in M in e ra l County.
Those are
where I f i r s t s tu d ie d the v o lc a n ic ash in flu e n c e d s o i l s , in
c o r r e l a t i o n o f s o i l surveys.
The Sheburne s e r ie s in. G la c ie r
County is s i m i l a r l y in flu e n c e d .
But a ls o in G l a c i e r County,
out on the gra ss -c ov ere d p i t t e d ground m oraine, near the
G l a c i e r Mountains, la y e r s o f v o lc a n ic ash measured in thickness
o f inches o r f e e t occur b u rie d s e v e ra l f e e t deep i n beds o f
ponds.
This c o n d itio n has been found in low places in i n t e r ­
mountain v a l l e y s .
V o lca n ic ash in flu e n c e d s o i l s l i k e in
Missoula and M in e ra l Counties can be expected to occur in
comparable high mountain landscapes i n L in c o ln , G l a c i e r ,
F la th e a d , Sanders, R a v a l l i , and Beaverhead C ounties.
(1 2 )
Northwest p a r t o f the s t a t e :
from Noxon to East G l a c i e r ,
re ac h in g low es t e le v a t i o n s in th e West.
(1 3 )
F la th e ad County, in p a rts o f the Bob M arshall W ild e rn e s s , and
o th e r p a r ts o f th e F lathead N a tio n a l Forest not in Flathead
County.
(1 4 )
From Canadian border south to Ham ilton where i t begins to fade
o u t.
The d i s t r i b u t i o n extends i n t o Idaho as f a r south as
M c C a ll. Ash is found in the Lubrecht Experimental F ore st but
fades e a s t o f th e r e .
(1 5 )
They a re e x te n s iv e over th e Lolo N a tio n a l
fo re s ts .
(1 6 )
Beaverhead N a tio n a l F o r e s t , m a in ly on the C o n tin e n ta l D i v i d e . .
The ash th in s o r is g r e a t l y mixed when going e a s t and south.
The B i t t e r r o o t Range shows th e l e a s t m ixing in the Beaverhead
w h i le the G r a v e lly and Madison Ranges have the most m ixing.
Can f i n d some ash i n f l u e n c e by Red Lodge.
(1 7 )
V o lc a n ic i n f l u e n c e in s o i l i s p r e v a l e n t throughout Idaho
(n o r t h o f the Salmon R iv e r ) and i n Western Montana.
(1 8 )
Has seen on th e Deer Lodge N a tio n a l F o re st as; f a r e a s t as
B o u ld e r, Montana and considers the F orest as being i n the
p e r ip h e r y o f ash d e p o s it s .
Thickness increases toward west.
F o re st and a d ja c e n t
57
(1 9 )
I have seen the brown s u rfa c e l a y e r on s o i l s in a l l counties
in Western Montana and have been t o l d th e brown s u rfa c e was
an i n d i c a t i o n o f th e presence o f ash.
(2 0 )
Yes o r so th e y a r e c a l l e d .
Near Coloma and a t o th e r high
e l e v a t i o n in Montana, Jewel B asin.
I am working on my.own
th e o r y o f B i r fo r m a tio n .
(2 1 )
North o f Couer d 'A l e n e , most o f th e mountain s o i l s have a
"loess cap" which c o n ta in s v a r y in g amounts o f v o lc a n ic ash.
Some, but not a l l , high energy aspects w i l l have l o s t t h i s
"loess cap" through e r o s io n .
(2 2 )
Ash caps in no rth c e n t r a l Idaho t h a t t h i n out to the south
a t th e Salmon R iv e r .
Up to 90 cm t h i c k e a s t o f Moscow w ith
th ic k e n in g when going i n t o the Palouse.
58
#2
HOW IS VOLCANIC ASH INFLUENCE RECOGNIZED IN THE FIELD?
(1 )
Low b u lk d e n s it y .
(2 )
The ash la y e r s we re co g n ize in th e Salmon R iv e r Mountains e a s t
o f Cascade, Ida h o , appear m o rp h o lo g ic a lly as A ( a l b i c ) horizons
They range in thic k n e s s to a p p ro x im a te ly 15 cm.
Colors are
gray and w h i t e , they run about 64% s i l t , less than 5% c l a y , and
th e r e s t i s fs and v f s .
The ash i t s e l f is c h i e f l y t u b u l a r
shards and glass encased phenocrysts.
Index o f r e f r a c t i o n o f
the glass ranges from 1 .4 9 7 to 1 .4 9 9 .
(3 )
Thin 0 to 15 o r 20 cm t h i c k , low b u lk d e n s i t y , loam to f i n e
sandy loam to s i l t loam t e x t u r e , reddish brown c o l o r , g e n e r a lly
no coarse fra g m e n ts , v ery c o n t r a s t in g boundary, weak f i n e
g r a n u la r s t r u c t u r e and on m o is te r landscape p o s itio n s are a l l
used to re co g n ize v o lc a n ic ash i n f l u e n c e .
(4 )
I use bulk d e n s i t y , s i l t loam t e x t u r e s , a b ru p t h o rizo n changes
to help reco g n ize loess in the f i e l d .
Many tim es these loess
d e p o s its sound hollow where th e y occur as a t h i n d e p o s it over
bedrock.
(5 )
Smeary f e e l r e s u l t i n g from high w a te r h o ld in g c a p a c i t y ; B i r
h o rizo n in d i c a t e s v o lc a n ic ash i n f l u e n c e .
Thickness is 60 cm
e a s t o f Moscow, Idaho and 60 cm a t Sandpoin t , Idaho..
(6 )
B i r i s n o t a good i n d i c a t o r by i t s e l f .
I t i s p a le brown to
n e a r ly w h ite w it h a sharp f e e l .
Very f i n e sand ( v f s ) is most
common.
In G l a c i e r County i t i s p o s s ib le to see e lo n g ate
p a r t i c l e s w it h sharp p o in ts using a hand le n s .
(7 )
Recognize by re d d ish c o l o r ( 7 . 5 YR 4 / 3 - 4 / 4 ) and a s i l t y c la y
loam t e x t u r e .
Occurs as an ashy loess mantle <1 f t . t h i c k .
The ash cap is mixed w ith o th e r m a t e r i a l s .
(8 )
B i r not always an i n d i c a t o r o f v o lc a n ic g la s s .
(9 )
R ecognition is by c o l o r , t e x t u r e , bulk d e n s it y .
Under most
c o n d itio n s the c o l o r i s 10 YR 5 / 4 to 5 /6 w ith m oist areas
having 10 YR 3 /2 to 3 /1 and South aspects having a g ra y e r c o lo r
The S t . Regis area has s i l t loam te x tu r e s w h ile the Kootenai
N a tio n a l F o re s t has sandy loam t e x t u r e s .
Thickness may be 10
59
to 15 cm on south aspects o r up to 55-60 cm but has an average
o f 30 to 45 cm t h i c k .
A t h i n discontinuous s u r fa c e A2 horizon
is p o s s ib ly the r e s u l t o f r e c e n t ash f a l l .
(1 0 )
Low b u lk d e n s i t y , f l o u r y when d r y , s i l t loam, g e n e r a l l y non
s t i c k y and non p l a s t i c .
(1 1 )
The unique and s t r i k i n g p r o p e r ty o f v o lc a n ic ash m antle on th e .
f o r e s t e d s o i l i s the s tro n g brown c o l o r o f the low d e n s i t y ,
massive s i l t loam, loam, o r g r a v e l l y o r stony s i l t loam or
loam t h a t r e s t s upon v a r i a b l e substratum o r upon the l i g h t gray
o r w h ite b u r ie d A o f the covered C ry o b o ra lf .
Even in the
development o f the A 2 -B ir z o n a tio n as in the Evaro and Sherburne
s e r i e s , the m a t e r i a l has th e same low d e n s ity massive c h a r a c te r .
M in e ral i d e n t i f i c a t i o n o f v o lc a n ic glass s hards , abundant in
these s o i l s a t t e s t to d e p o s itio n from atmospheric suspension
as in loess d e p o s its .
(1 2 )
A combination o f brown c o l o r (as i n B i r ) , low b u lk d e n s ity
( 0 . 8 - 1 . I ) , and f l u f f y , weak s t r u c t u r e .
Brown c o l o r alone is
no t a good i n d i c a t o r .
(1 3 )
The ashy m antle i s loess te x tu r e d and is a 10-20 cm t h i c k l a y e r
when pure.
I t is commonly brown b u t may be d a r k e r and almost
b la c k as when found in an avalanche chute (due to the grass
v e g e ta tio n in these c h u te s ).
(1 4 )
Found as a brown B2 ashy m a n tle , chromas 4 or g r e a t e r (some­
times as high as 8 ) , a b ru p t low er boundary and low bulk d e n s it y .
(1 5 )
G e n e r a lly by c o l o r (r e d d is h brown) and t e x t u r e ( s i l t loams and
v ery f i n e sandy loams).
(1 6 )
S i l t t e x t u r e and reddish brown c o l o r as a 10-20 cm s u rfa ce
m a n tle.
Also high o rg a n ic m a tte r w ith a f i n e r o o t mat.
(1 7 )
The s u r fa c e s o i l c h a r a c t e r i s t i c s are r e a d i l y re co g n ize d .
A
sharp d i s c o n t i n u i t y between th e t e x t u r e o f the s u rfa c e and
u n d e r ly in g horizons is v i s i b l e and e a s i l y determ ined.
(1 8 )
Low b u lk d e n s i t y ; b r i g h t y e llo w brown c o lo r (10 YR 4 / 4 - 3 / 4 ) ,
p o s s ib ly 7 .5 YR; few coarse fragments and a s i l t loam o r loam .
t e x t u r e a re a l l used.
T h ic k e s t d e p o s its a re 35 cm and may have
60
a t h i n A2 on the s u r fa c e .
Average o f 15 to 20 cm t h i c k .
seen as an Al h o rizo n a few t i m e s . .
Has
(1 9 )
Brown B i r ashy m antle may i n d i c a t e i n f l u e n c e , bu t u n c e rta in
t h a t th e c o l o r i s from v o l c a n i c . a s h . .
(2 0 )
As c o n v e n t io n a lly described - a reddish brown l i g h t w eight
horizon a t th e s u rfa c e or beneath a shallow A l , w it h (o f t e n
but not alw ays) re c o g n iz a b le ir o n c o n c r e tio n s , o r o th e r
c o n c re tio n s .
(2 1 )
The v o lc a n ic ash presence i s i n f e r r e d wherever the "loess cap"
is found.
L a b o rato ry a n a ly s is on some s c a tt e r e d s o i l s provides
th e b a s is f o r t h i s i n f e r e n c e .
(2 2 )
A re d d ish te a c o lo re d B i r t h a t may c o n ta in a t h i n A on to p ,
soapy f e e l r e s u l t i n g from t h i x o t r o p i c c h a r a c t e r , s i l t loam
t e x t u r e , weak f i n e medium g r a n u l a r s t r u c t u r e , low bulk d e n s ity
from . 8 8 - , 9 5 , and a n o n - p la s t i c and v ery s l i g h t l y s t i c k y con­
s is te n c y a re a l l used.
61
#3
HOW IS VEGETATION RELATED TO VOLCANIC ASH INFLUENCE?
(1 )
The areas w it h the s o - c a l l e d brown s u rfa c e u s u a l l y do not have
ponderosa p in e .
(2 )
Lodgepole p i n e , Engelmann spruce and subalp in e f i r
grow on the ash d e p o s its .
(3 )
G e n e r a lly t h i c k e s t under s u b a lp in e f i r ty p e s , much t h i n n e r
o r absent under open canopy ponderosa pine o r Douglas f i r .
I b e l i e v e t h i s is due to e r o s iv e fo rc e s being more a c t iv e
on the warm s o u th e r ly exposures t h a t are s p a r s e ly v e g e ta te d .
Have seen t h i c k l a y e r under grass on the C le a rw a te r N a tiona l
F o r e s t.
(4 )
In the h ig h e r e le v a t i o n s i t appears t h a t the loess deposits
may be s u p p o rtin g grasses and forbs w h ile the rocky knobs
o r g l a c i a l t i l l d e p o s its support a mixed stand o f subalpine
f i r , w h ite bark pine o r Engelmann spruce t r e e s .
I do not
know why v e g e t a t i v e p a tte r n s o c cu r.
The Yellowmule area south .
o f the West Fork o f the G a l l a t i n R iv e r is a v ery good example
o f th is p a tte rn o f v e g e ta tio n .
I have thought t h a t a e r a t i o n ,
te m p e r a tu re , o r m o istu re c o n d itio n s may e x p la in th e in flu e n c e
o f loess on v e g e t a t i v e p a t t e r n s .
(5 )
An i n t a c t l a y e r o f ash is found under grand f i r , western red
c e d a r, and w estern red c ed a r-w e stern hemlock zones.
Under
grasslan d v e g e ta tio n i t is mixed w it h o th e r s o i l - probably
washed from slopes la c k in g a p r o t e c t i v e f o r e s t cover a t the
tim e o f a s h f a l l .
*
■
(6 )
I have no knowledge.
(7 )
In t h i s area ash caps are s t r o n g l y ass o c iate d w i t h f o r e s t s o i l s
( f o r e s t v e g e ta tio n in c lu d in g ponderosa pine and w e t t e r s i t e s ) .
There are v ery few re c o g n iz a b le caps found in s o i l s developed
under g rasslan d in t h i s a r e a .
(8 )
A ssociated w ith s u b alp in e f i r - c l i m a x v e g e ta tio n type or
Douglas f i r going to s u b a lp in e f i r .
(9 )
A s s o c ia tio n w it h lodgepole pine and o th e r f o r e s t types but
not ponderosa p in e .
fo r e s ts a l l
62
(1 0 )
Since most o f my areas are d e riv e d from coarse g ra in e d
b a t h o l i t h a ss o rte d r o c k s , h a b i t a t types tend to be m o is te r
ones than norm al.
(1 1 )
I do not know i f th e r e is a t r u e v e g e t a t i o n - s o i l c o r r e l a r y
a s s o c ia te d w ith th e v o lc a n ic ash i n f l u e n c e ; f o r a t th e high
e le v a t io n s o f th e Andeptic C ry o b o ra lf s , the C ryan depts, Andie
Cryochrepts and C ry o rth o d s , they a re under s u b a lpine f i r ,
Engelmann spruce and lodgepole pine and on south and west
exposures under grass as in th e Buckhouse s e r i e s .
In Idaho
and in Montana v a l l e y s a d ja c e n t to Idaho the Krause and
Waits s o i l s on s lo p in g to le v e l stream t e r r a c e s a re under
Douglas f i r and p o s s ib ly a ls o under ponderosa p in e .
(1 2 )
R e la tio n s a re v ery broad.
(1 3 )
SW aspects w ith r e s id u a l s o i l s seldom have an ash m a n tle , but
may have an ash in flu e n c e d solum.
(1 4 )
R e lated to wet f o r e s t zones l i k e Western La rch, s u b a lp in e ,
f i r , cedar hemlock, spruce but not under ponderosa pine or
Douglas f i r .
(1 5 )
V e g e ta tio n communities a re r e l a t e d q u i t e p r e d i c t a b l y to the
ash mantled s o i l s , b u t both the v e g e ta tio n and th e ash seems
to be c o n t r o l l e d by the lo c a l c lim a te r a t h e r than by each
o th e r.
D ire c t c o r r e la tio n .
(1 7 )
Subalpine t u r f a t 2550 m + e l e v a t i o n .
(1 8 )
Thickness in c re a se s w it h v e g e ta tio n ass o c iate d w it h h ig h e r
e l e v a t i o n s . T h ic k e s t s o i l s a re under s u b a lp in e f i r where an
A2 may be found.
(1 9 )
A ssociated w it h most a l l
(2 0 )
N e a rly always f i n d s p r u c e - f i r on B i r or o c c a s io n a lly lodgepole
(2 1 )
I d o n 't know how v e g e ta tio n is r e l a t e d to v o lc a n ic ash
in flu e n c e .
S everal h a b i t a t types occur on these m a t e r i a l s .
A general f e e l i n g is t h a t the loess cap is th e b a s is f o r
v e g e t a t i v e p r o d u c t i v i t y on g l a c i a t e d a rea s .
f o r e s t ty p e s .
63
(2 2 )
The depth o f the loess cap has. an. i n f lu e n c e in th e regenera
t i o n c a p a b i l i t y o f a s o i l . This i s e s p e c i a l l y t r u e i f the
s o i l would be droughty w ith o u t th e loess cap.
64
#4
IS ELEVATION OR TOPOGRAPHIC POSITION RELATED TO VOLCANIC ASH
INFLUENCE?
(1 )
The s o - c a l l e d brown s u rfa c e is m a in ly a t high e le v a t io n s on
south sides o f m ountains, b u t continues to low er e le v a t io n s
a t n o rth s lo p e s .
(2 )
Bottomlands f a v o r the p r e s e r v a t io n o f the ash.
(3 )
North aspects and h ig h e r e l e v a t i o n s have t h i c k e r ash in flu e n c e
because o f th e t h i c k e r v e g e t a t i v e cover on these s i t e s .
Southwest aspects a re more e r o s iv e due to the p r e v a i l i n g
winds and more f r o s t a c t io n e s p e c i a l l y in l a t e s p r in g when
ic e p e d e s t a l ! ing begins.
(4 )
Yes.
I f e e l t h a t c e r t a i n f a c t o r s a f f e c t the d e p o s itio n o f
loess a n d /o r more a p t to r e t a r d th e subsequent loss o f loess
by e r o s io n a l processes.
I have observed most o f th e loess
d e p o s its above 2580 m e l e v a t i o n along a lp in e r id g e s and
c ir q u e b a s in s .
Very l i t t l e e ro s io n is o c c u rrin g in many o f
these a lp in e c ir q u e b a s in s .
I have a ls o observed more loess
on th e l e e s id e o f wind swept rid g e s on th e n o rth e rn exposures.
I suspect t h a t v e g e ta tio n may have re ta rd e d e ro s io n on some
o f these north exposures, w h ile the loess may have been
s t r i p p e d from th e wind swept southern exposures.
(5 )
North aspects have deeper and more continuous loess caps.
On
south slopes loess caps a re no t common.
P re c ip ita tio n d is ­
t r i b u t i o n is c o r r e l a t e d w ith th e ash l a y e r more than is a s p e c t,
e s p e c i a l l y where annual p r e c i p i t a t i o n is 100 to 125 cm.
(6 )
Found in areas not prone to e ro s io n by wind or w a t e r .
G e n e r a lly on n o rth slopes w ith depth in c r e a s in g a t h ig h e r
a ltitu d e s .
(7 )
No leeward t h ic k e n in g .
(8 )
On the Kootenai N a tio n a l F o re s t th e loess cap is r e l a t i v e l y
uniform in th ic kn es s on a l l aspects and a t a l l e l e v a t i o n s .
th e S t. Regis a re a th e th ic kn es s increases w ith e l e v a t i o n .
O ld er stream t e r r a c e s may have t h i c k e r deposits ( 4 5 -4 8 cm)
due to r e d e p o s itio n a f t e r e r o s io n from south a sp e c ts .
In
65
(9)
The e a s t most e x t e n t o f v o lc a n ic ash in f lu e n c e on s o i l s in
Montana is on high mountain slopes where on fo r e s t e d e a s t and
n o rth fa c in g slopes the v o lc a n ic ash mantle extends down slope
s e v e ra l hundred f e e t low er e l e v a t i o n than on south and west
fa c in g expos ure s . The v o lc a n ic ash m antle occurs a t lower
e le v a t i o n s and on o ld stream t e r r a c e s a d ja c e n t to Idaho.
(1 0 )
V o lc a n ic ash i n f l u e n c e g e n e r a l l y occurs o r is deeper on
n o r th e a s t s lo p e s ; o f t e n absent on steep south fa c in g b r e a k s ,
p o s s ib ly due to sparse v e g e ta tio n .
(11)
North and e a s t aspects and high e le v a t io n s have g r e a t e s t degree
o f i n f l u e n c e as shown by t h i c k e r l a y e r s .
(1 2 )
Ash cap not on south aspects a t e le v a t i o n s as low as (high
b a s in s , e t c . ) on no rth s lo p es .
(1 3 )
Most common a t high e l e v a t i o n s because p r e c i p i t a t i o n c o r r e l a t e s
p o s i t i v e l y w it h e l e v a t i o n .
An e x c e p tio n is Thompson F a l ls and
west.
(1 5 )
B e t t e r preserved on s t a b l e landforms a t h ig h e r e l e v a t i o n s .
(1 6 )
High energy south aspects u s u a l l y la c k an ash m a n tle.
(1 7 )
M o s tly on r id g e to p s , north e a s t c ir q u e - l i k e basins o r w e l l p r o te c te d n i v a t i o n a rea s .
(1 8 )
Found on a l l a s p e c ts .
In Lake County i t occurs down to e le v a ­
t i o n s o f 990 m which are th e toe slopes o f the M ission Mountains
In Lake County e l e v a t i o n is a poor i n d i c a t o r o f th ic kn es s even
on the same s lo p e ; however, in G r a n ite County t h e r e seemed to
be a l i t t l e more c o r r e l a t i o n between thic k n e s s and e le v a t i o n
on th e same slope ( t h i c k e r a t th e h ig h e r e l e v a t i o n s ) .
(19)
"Ash" in flu e n c e d s o i l s a re u s u a l l y a t h ig h e r e l e v a t i o n s , always
in f o r e s t , and o f t e n on n o rth slopes - th e r e a re exceptions
here bu t not many.
Ash in flu e n c e d s o i l s r a r e l y occur in low
p la c e s , draws, de pres s ions.
(2 0 )
Depth is v a r i e d .
Topographic i n f lu e n c e i s s p o r a d ic ; we have
"loess shadows" o c c u r r in g o v er th e f o r e s t .
The cap becomes
more mixed w ith u n d e rla y in g m a t e r i a l as e l e v a t i o n in c re a s e s .
66
This probably r e l a t e d to c r y i c land forming processes such
as c r y o p la n a t io n .
(2 1 )
This is answered in p a r t f o r the f i r s t q u e s tio n .
High e le v a ­
t i o n areas t h a t have s o i l m ixing due to fr e e z e -t h a w processes
do n o t have th e "loess cap" c h a r a c t e r i s t i c s t h a t a re ass o c iate d
w it h v o lc a n ic ash.
In some o f these areas I t h i n k ash
i n f l u e n c e w i l l be found when la b work is done.
67
#5
ARE THERE ANY RELATIONSHIPS BETWEEN VOLCANIC ASH INFLUENCE
AND UNDERLYING BEDROCK?
(I)
Not n e c e s s a r i l y , however, some t h i n k i t is less l i k e l y to have
brown s u r fa c e o v er lim e s to n e .
I cannot prove t h i s .
(3)
None observed.
(4 )
Thus f a r I have not seen t h i s to be a f a c t o r .
I have observed
loess d e p o s its on T e r t i a r y v o l c a n i c s , Precambrian g n e is s ,
Cretaceous groups; hence, the f u l l range o f rock ty p e s .
I
have observed more widespread occurrence o f loess i n the
v o lc a n ic s on th e G a l l a t i n ( N . F . ) .
(5 )
No.
Found on Palouse loess and o th e r form a tio n s o f Northern
Idaho.
(6 )
Not to my knowledge.
(7 )
More common on more permeable M is s is s ip p ia n lim es to n e because
o f less s u rfa c e e r o s io n .
Loess caps on a l l types o f g l a c i a l
d e p o s its i n c lu d in g heavy t i l l .
(8 )
Calcareous p a r e n t m a t e r i a l s have l e s s .
(10)
No.
(1 1 )
The v o lc a n ic ash m antle s o i l s d e r iv e d from q u a r t z i t e s , sand­
s to n e s , g r a n i t e s and lim e s to n e .
There is no r e l a t i o n s h i p w ith
u n d e r ly in g rock except as these rocks occur a t p r e d ic te d high
o r low mountain e le v a t i o n s in th e e a s te rn most e x t e n t o f the
Rocky Mountain system.
(1 2 )
No.
U s u a lly c o n t r a s t in g .
Occurs over g r a n i t e , a r g i l l i t e ,
v o lc a n ic r o c k s , t e r r a c e and stream a llu v iu m ( o f t e n b u r i e d ) .
This makes i t a unique d e p o s it .
(1 3 )
M ixing may add m a t e r i a l from below by f r o s t a c t io n and churning
In f i n e - t e x t u r e d w ea th e rin g products th e ash cap may appear to
be deep but the % glass is small due to m ixin g .
I f the cap
is over compacted t i l l , loss by e ro s io n may have occurred due
to low er p e r m e a b i l i t y in th e t i l l .
68
(1 4 )
R a re ly is ash found on lim e s to n e .
Ralph Dunmire says t h i s
not so. Ash i s on lim es to n e a t Lubrecht.
is
(1 5 )
Not observed to be o f any s i g n i f i c a n c e - we have ash mantles
on r e s i d u a l , g l a c i a l and a l l u v i a l p a re n t m a t e r i a l s .
(16)
Ash s o i l s over lim es to n e o r "hard" bedrock a re much more
c r i t i c a l in terms o f e ro sio n (c r e a te s a stone pavement).
Ash
o v er s h a le i s le s s c r i t i c a l because eroded areas have some
c a p a c ity to r e v e g e t a t e .
(1 9 )
The brown l a y e r i s p re s e n t on s o i l s formed from m a t e r i a l s
c o n ta in in g calc are o u s rock fr a g m e n ts ; however, th e brown
l a y e r i s no t as t h i c k o r i t takes lo n g e r to form on such s o i l s
than on comparable p o s itio n s w i t h s o i l s from m a t e r i a l s con­
t a i n i n g non-calcareous ro c ks .
P o s s ib ly t h i s could be a r e s u l t
o f th e s o i l f r a c t i o n being s m a lle r ( h ig h e r s i l t c o n te n t) and
consequently having a much l a r g e r s u rfa c e area o f p a r t i c l e s
i n which th e c o l o r in g agent would have to c o a t.
The brown ash
i s no t low enough i n Lake County to be a s s o c ia te d w ith G la c ia l
Lake M issoula m a t e r i a l s .
(2 0 )
No - have found B i r on lim es to n e and on g r a n i t e s o i l s .
(2 1 )
Most o f the lan d between Canada and Coeur d 'A le n e has been
g l a c i a t e d to v a ry in g d e g re e s ; t h e r e f o r e , most s o i l s a re not
from r e s id u a l m a t e r i a l s .
The amount o f t r a n s p o r t i n g and
m ixing by g l a c i a t i o n v a r ie s from area to a re a .
(2 2 )
Loess caps tend to be eroded and t h i n n e r over impermeable
bedrock (w eakly f r a c t u r e d g r a m * t i c s ) .
69
#6
WHAT IS THE IMPORTANCE OF VOLCANIC ASH INFLUENCE FOR
PURPOSES OF LAND MANAGEMENT?
(I)
Does not f e e l the ashy m antle is as e r o d i b le o r as p ro d u c tiv e
as th e F o re s t S e rv ic e m a in t a in s .
(3 )
The t h i n v o lc a n ic ash l a y e r is im p o rta n t f o r v e g e t a t i v e pro­
d u c tio n because o f i t s more f a v o r a b l e chemical and physical
p ro p e rtie s .
Excessive d is tu rb a n c e such as t h a t which is
sometimes caused by t e r r a c i n g and slash p i l i n g w i t h heavy .
equipment w i l l remove the ash l a y e r and expose th e much less
f e r t i l e subsu rface m a t e r i a l t h a t i s more d i f f i c u l t to revege­
ta te .
This is e s p e c i a l l y t r u e in th e sandy g r a n i t i c s o i l s
which have low in h e r e n t f e r t i l i t y .
The s i l t s i z e ash p a r t i c l e s
can become a d u s t problem on unsurfaced roads.
Slash burning
e s p e c i a l l y i f wind rowed o r p i l e d decreases p e r m e a b i l it y f o r
I to I h y e a r s .
Erosion a problem a f t e r a f i r e f o r o n ly a
s h o r t tim e .
(4 )
One management concern in th e high e l e v a t i o n i s t h a t o f the
low b u lk d e n s it y and th e i n f l u e n c e o f wind e r o s i o n , d r y in g ,
and f r o s t heaving on th e a lp in e t u r f s .
Thus, once these a lp in e
t u r f mats are broken up and s o i l is exposed, these areas are
d i f f i c u l t to r e g e n e ra te due to the f a c t o r s p r e v io u s ly l i s t e d .
(5 )
F e r t i l i t y may be reduced due to phosphorus f i x i n g c a p a c ity of.
these s o i l s , evidence is not complete y e t .
(P resented to ASA,
SSSA Annual Sunrner M e e tin g , 1 9 7 5 .)
Very e r o s iv e and w ith
high w a t e r h o ld in g c a p a c ity .
(6 )
This is p robably the area where we need in fo r m a tio n now. We
know we have these s o i l s and have made p r o v is io n i n the s o i l
c l a s s i f i c a t i o n to s e p a ra te them a t the fa m i ly p a r t i c l e class
le v e l.
There i s l i k e l y more in fo r m a tio n a v a i l a b l e on use and
management than I am aware o f .
(7 )
Has h ig h e r s i t e index than i f removed.
More manageable
because o f low er stone c o n te n t.
E a s ie r to p l a n t t r e e s , e t c .
(8 )
The B i r i s not any more im p o rta n t than any o t h e r f o r e s t s o i l .
I t is not as e r o s iv e nor as f e r t i l e as is regarded by some
e s p e c i a l l y s in c e th e % base s a t u r a t i o n i s les s than 50% in
many o f these s o i l s .
70(9 )
The loess m antle c onta ins most o f the n u t r i e n t v a lu e o f the
s o i l and i s high i n N and P.
The e ro s io n hazard is high i f s o i l is bare f o r any len gth o f
tim e .
Drying by f i r e o r dry s p e l l s o n ly t e m p o r a r ily decreases
p e rm e a b ility .
Rew etting by w i n t e r snow or r a i n r e tu r n s
th e loess cap to i t s norm a lly high p e r m e a b i l it y .
(1 0 )
Increased f e r t i l i t y from ash i n f l u e n c e .
CEC f o r pure loess
w ith 45% ash i s in the range o f 26 to 30 meg/IOOg. Water
h o ld in g c a p a c ity i s g r e a t e r .
(1 1 )
The v o lc a n ic ash m a n tle , because o f i t s low volume w eig h t and
m a s s i v e - f lo u r l i k e c h a r a c t e r , erodes badly by r a i n f a l l o r wind
where unp ro te c te d by v e g e t a t i v e co ve r.
F o re st management in
c le a n up a f t e r tim b e r c u t t i n g precludes the t r a c t o r drawn
windrowing o f h a r v e s t r e s id u e f o r b u rn in g .
The high a f f i n i t y
o f th e ash f o r w a t e r , o rg a n ic humus and bases in c re a s e the
p r o d u c t i v i t y o f th e v o lc a n ic ash in flu e n c e d s o i l o v er comparable
te x t u r e d s o i l s on l i k e topography under s i m i l a r tem perature
and r a i n f a l l .
But t h i s comparison o f pro d u c tio n is d i f f i c u l t
to make, l o c a l l y , because th e v o lc a n ic ash i n f l u e n c e is con­
tinuous and comparably te x t u r e d ash and non-ash in flu e n c e d
s o i l s w i l l d i f f e r a p p r e c ia b ly i n te m peratu re a t th e hig h e r
and low er e le v a t i o n s o f s e v e ra l thousand f e e t .
(1 2 )
F e r t i l i t y depends on how w e ll th e s o i l s u i t s th e p l a n t growing
on i t , so I c a n ' t say i f i t i s f e r t i l e o r n o t.
F i r e may have,
e f f e c t on these s o i l s i f hot enough.
Weak s t r u c t u r e makes i t
e r o s iv e on s lo p e s .
(1 3 )
The ash cap is f e r t i l e and has high w a te r h o l d i n g , high
i n f i l t r a t i o n , and high c a t io n exchange c a p a c i t i e s so. i t should
be p r o te c te d .
.
(1 4 )
Burning may e f f e c t m i c r o f l o r a (n o t only ash p roble m ).
Slash
p i l i n g w i t h heavy equipment may cause the B2 to be c oncentrated
in some a r e a s , reduced in o t h e r s .
Most o f the n u t r i e n t and
w a t e r r e t a i n i n g c a p a c ity i s in th e B i r h o r iz o n .
(1 5 )
Very im p o rta n t - has a d i r e c t and s i g n i f i c a n t e f f e c t on e rosion
r e g e n e r a t i o n , p l a n t i n g te c h n iq u e s , h a rv e s t methods, e t c .
71
(16)
Dust is a problem in the f a l l when the area d r i e s , e s p e c i a l l y
on the west s id e o f th e B i t t e r r o o t d i v i d e .
Also the s o i l
has:
a)
b)
c)
High s u s c e p t i b i l i t y to f r o s t heaving e s p e c i a l l y on road
cuts
Very high m o istu re h o ld in g c a p a c i t y , e s p e c i a l l y in suba lp in e t u r f
E a s i l y eroded under g ra z in g a t h ig h e r e l e v a t i o n s , t h e r e f o r e
e ro s io n i s c r i t i c a l to watershed s t a b i l i t y .
(1 7 )
High exchange c a p a c ity in th e s u rfa c e and low er in the B e l t
s u b -s u r fa c e .
(18)
Shallow road cuts may produce dust problem.
Ash m antle is
v e ry p r o d u c t iv e , so I recommend le a v in g sla s h so as not to
d i s t u r b a m a n tle .
G r a n it e s o i l s need the cap f o r f e r t i l i t y .
(1 9 )
The brown l a y e r is s t r o n g l y a c i d , low in base s a t u r a t i o n , low
in a v a i l a b l e w a te r h o ld in g c a p a c i t y , and probably due to i t s
dark c o l o r would absorb more s o l a r heat i f exposed and thus
c r e a t e h ig h e r s o i l tem peratures and e v a p o t r a n s p i r a t i o n ; a l l
o f which would r e s u l t in a p oore r media f o r r e v e g e t a t i o n .
T h e o r e t i c a l l y i t should be v e ry h i g h l y e r o s iv e m a t e r ia l i f
exposed ( f i n e p a r t i c l e and ped s i z e and low b u lk d e n s i t y ) ;
however I have not been a b le to l o c a t e any r e a l evidence o f
s e v e r e ly eroded areas even i n c l e a r c u ts .
(2 0 )
We a re s tu d y in g t h i s as a s i d e l i n e .
processed a t t h i s tim e .
(2 1 )
The loess cap has a low b u lk d e n s i t y .
I t seems to be s u b je c t
to compaction under c r i t i c a l m o istu re regim es, w i t h . a d e f i n i t e
e f f e c t on p l a n t growth.
(2 2 )
The ash i s im p o r ta n t f o r f e r t i l i t y when over g r a n i t e and is
e s s e n tia l fo r re v e g e ta tio n .
I t has e x c e l l e n t c a t io n r e t e n t i o n
c a p a c i t y , is v ery d u s ty , and i s not t h i c k enough to slump.
The data have not been
72
#7
DO VOLCANIC ASH INFLUENCED SOILS HAVE ANY OTHER PECULIAR
CHARACTERISTICS?
(1 )
High 15 b a r w a te r c o ntent ( 6 . 6 ) may i n d i c a t e t h a t e i t h e r
a llo p h a n e o r o rg a n ic m a tte r i s im p o r ta n t.
I t h i n k t h a t the
s o - c a l l e d brown s u rfa c e i s a pedogenic development.
I t is
l i k e l y t h a t some o f the o th e r s u rfa c e s have as much ash but
i t h a s n 't weathered i n t o a brown s u r fa c e .
Appear to be found
where snow is n o rm a lly deep enough to p re v e n t f r e e z i n g during
most w i n t e r s .
(2 )
The F o re s t S e r v ic e has experien ced poor s u r v i v a l o f spruce
s e e d lin g s in many o f these s i t e s .
We do not f e e l i t is
r e l a t e d to the p r o p e r t i e s o f the te p h ra d e p o s it s .
R a th e r,
the top o g ra p h ic f e a tu r e s which f a v o r p r e s e r v a t io n o f the ash
(b o tto m lan d s) i n f l u e n c e m ic ro c lim a te s on these s i t e s , and
th e y a c t as cold a i r drainages and cold a i r p ockets.
(3 )
Bulk d e n s i t y , c a t io n exchange c a p a c t i y , o rg a n ic carbon c o n te n t,
and p e rc e n t o f p y r o c l a s t i c m a t e r i a l in th e s i l t and sand
fra c tio n s .
Also o f concern a re th e e f f e c t s o f h o t f i r e s on
these s o i l s .
Do th e y become hydrophobic, and i f so, how long
does t h i s c o n d itio n l a s t ?
I
(4 )
I am no t c o m p le te ly assured t h a t what I have seen on the
G a l l a t i n N a tio n a l F o re st is v o lc a n ic loess o r l o c a l i z e d loess
d e p o s it s .
I suspect t h a t what I have observed i s l o c a l i z e d
lo e s s .
However, th e r e appears to be many p o in ts o f s i m i l a r i t y
where v o lc a n ic ash o r l o c a l i z e d loess should respond comparably
because t h e i r p a r t i c l e s iz e s a re o r can be f a i r l y s i m i l a r .
Those questions which respond comparably are # 2 , 4 , 5 and
o n ly p a r t i a l s i m i l a r i t y on #6.
(5 )
Phosphorous a b s o rp tio n may be r e l a t e d to Mn + Fe from common
c o n cre tio n s o r to a llo p h a n e .
Thickness o f v o lc a n ic ash v a r ie s
from 60 cm e a s t o f Moscow to 50 cm a t Sandpoin t , w ith th in n in g
to th e e a s t and s outh.
In the S e l k i r k Mountains th e ash is
unweathered a t high e l e v a t i o n s .
(6 )
When not b u rie d v o lc a n ic ash may be mixed by ro o ts o r a n im a ls ,
le a v in g a low percentage o f ash in s u rfa ce s o i l .
(7)
Has f i n e r t e x t u r e than w estern loess caps.
Loess caps w ith
s i I t e x t u r e show a more pronounced t h i x o t r o p y than the more
73
h i g h l y weathered s i cl loess cap.
In regards to needs f o r
a d d i t i o n a l in fo r m a tio n about v o lc a n ic ash in flu e n c e d s o i l s :
a)
b)
c)
d)
We need more lo c a l data on ash c o n te n t o f the cap to
a d eq u ate ly c l a s s i f y these s o i l s a t the f a m i ly l e v e l o f
the s o i l taxonomy.
S o il m o is tu re r e l a t i o n s h i p s w i t h i n and f e r t i l i t y s ta tu s
o f th e caps should be q u a n t i t a t i v e l y dete rm in e d .
I t is
w id e ly assumed t h a t ash caps a re s u p e r io r in these respects
to o t h e r p a r e n t m a t e r i a l s , bu t th e r e is l i t t l e documenta­
t i o n to support t h i s assumption.
I f ash caps a r e a s u p e r io r p l a n t growth medium, how much
g r e a t e r i s p r o d u c t i v i t y on them than on s i m i l a r s o i l s
w it h o u t caps? Is p r o d u c t i v i t y r e l a t e d to th e thickn ess
o f th e cap?
What e f f e c t do logging p r a c t ic e s which d i s t u r b o r re arra n g e
th e caps have on s i t e q u a l i t y , p a r t i c u l a r l y dozer p i l i n g
o f lo g g in g slash?
I t h i n k th e b a s ic p h y sic a l c h a r a c t e r i s t i c s o f th e loess caps
found in v ario u s p a r ts o f th e S t a t e would be the most im portant
i n fo r m a tio n needed.
(8 )
The brown ( B i r ) s u r fa c e a s s o c ia te d w ith v o lc a n ic ash may be
th e r e s u l t o f pedogenesis and n o t from v o lc a n ic ash a lo n e .
I t may be a r e s u l t o f the environm ent a s s o c ia te d w ith subalp in e
fir.
The degree o f B i r fo rm a tio n is a s s o c ia te d w it h p a r e n t m a t e r i a l s .
D o lo m itic and c alcareous B e l t rocks d o n 't have a brown s u rfa ce
a t e le v a t i o n s as low as th e noncalcareous B e l t rocks.
The s i l i c a t h a t is a s s o c ia te d w it h amorphous c h a r a c t e r of.
the B i r may have come p a r t l y from p l a n t opal p h y t o l i t h s and
not v o lc a n ic ash a lo n e .
(9 )
The p a r t i c l e s iz e d i s c o n t i n u i t y between the loess cap and
b u r ie d s o i l i s s t r i k i n g .
(1 0 )
O ften p re se n ts w hat appear to be a spodic h o rizo n b u t in
r e a l i t y is due t o ir o n r i c h w ea th e rin g products.
(1 1 )
S p ec ia l s tu d ie s o f the c h a r a c te r o f th e glass shards i n the
v o lc a n ic ash m antle show a weak to moderate degree o f change
o r w ea th e rin g o f th e glass s h ard s , b u t s t i l l re c o g n iz e a b le
as glass s hards .
Y et i n Montana th e w e a th e rin g is s u f f i c i e n t
74
t h a t i r o n has been re le a s e d o r r e t a in e d from th e s o l u t i o n o f
o r g a n ic m a tte r in s o l u t i o n o r suspension from th e f o r e s t l i t t e r
as i t passes through th e ash m a n tle .
Other development o f the
B i r h o riz o n as i n Orthods is weak - having s t a r t e d w ith a
massive m a t e r i a l having any amorphous c la y in c r e a s in g in
q u a n t i t y w i t h inc re a se d w e a th e r in g .
(1 2 )
May be phosphate d e f i c i e n c y i n th e v o lc a n ic ash in flu e n c e d
s o ils .
Probably c o n ta in a llo p h a n e .
Under microscope e x h i b i t s
shards and much r e l a t e d m a t e r i a l v ery d i f f i c u l t t o i d e n t i f y
because o f w e a th e rin g regim es.
Ash (g la s s c o n te n t) v a r ie s
from 5 to 6 0 % .
Needs study in the area o f f e r t i l i t y .
(1 3 )
The ashy m antle may not c o n ta in v o lc a n ic ash in some E n tic
spodosols found in cold wet a r e a s .
S o ils never f r e e z e Under
th e ash cap - pro b a b ly from th e i n s u l a t i o n .
Base exchange
c a p a c ity would be good to know.
(1 4 )
High phosphate f i x i n g c a p a c ity ( a t l e a s t in C h i l e ) , high c a t io n
exchange c a p a c ity i f measured as c a t io n exchange c a p a c ity f o r
th e c la y f r a c t i o n , high w a t e r h o ld in g c a p a c i t y , low. bulk
d e n s i t y , and a llo p h a n e .
Sample throughout th e a s h f a l l d i s t r i ­
b u tio n f o r chemical and m in e r a lo g ic a l a n a ly s is and compare w ith
th e u n d e r ly in g s o i l .
(1 6 )
Lab a n a ly s is i s needed to d e term ine how much o f the s i l t y s u r­
faces a re in flu e n c e d by v o lc a n ic ash, e s p e c i a l l y in the e a s te rn
p art o f its d is trib u tio n .
(1 7 )
Popcorn pumice found n e ar the Phillipsburg-Drummond area
in d i c a t e s t h a t v o lc a n ic ash d id not n e c e s s a r ily come from as
f a r as th e Cascade Range.
(1 8 )
Burning does no t n e c e s s a r i l y cause e ro s io n but may g iv e a
hydrophobic c h a r a c te r to th e m a n tle .
In fo r m a tio n on w ater
re la tio n s h ip s , i . e . , p la n t a v a ila b le w ater; i n f i l t r a t i o n
ra te s , e tc .
Also chemcial in f o r m a t i o n , i . e . . C ation Exchange
C a p a c ity , base s t a t u s , e t c .
Also i t would be i n t e r e s t i n g
to document the e f f e c t o f f i r e on these s o i l s .
(1 9 )
An o d d i t y o c c u r r in g in Lake County is a p o o r ly d ra in e d a l l u v i a l
s o i l having a t h i n l a y e r near th e s u rfa c e looks to me to be
s i m i l a r to the brown s u rfa c e l a y e r on tim bered mountain s lo p es .
This t h i n l a y e r , even though s a t u r a t e d w ith w a t e r during much
o f th e growing season, s t i l l has the b r i g h t chroma's ( / 4 , / 5 )
75
o f a w e ll d ra in e d s o i l .
A f t e r removing th e n a t i v e Englemann
spruce f o r e s t from t h i s s o i l and p r o v id in g d r a in a g e , grasses
do v e ry p o o rly on i t .
a)
b)
Why is th e C a tio n Exchange C a p a city v a r i a b l e i n th e B i r
from s o i l to s o i l , e s p e c i a l l y in the Felan 1970 Missoula
County 3 2 -2 and Wishard 6 4 - 3 1 - 3 .
Why is the 15 b a r w a te r :
c la y r a t i o in Felan the way i t
is.
c)
d)
Why i s th e r e such a wide v a r i e t y o f clays ( c h l o r i t e ,
v e r m ic u li t e ) in th e B i r o f Felan and o th e r s .
Why in Lake County is the B i r found as low as 1080 m on
southwest aspe c ts .
(2 0 )
I would l i k e to have time and funds to pursue my t h e o r ie s on
these s o i l s .
I b e l i e v e t h a t we need to know much more about
them b e fo re we p r e s c r ib e management o f s p r u c e - f i r and o th e r
high e l e v a t i o n f o r e s t s w it h t h i s type o f s o i l .
(2 1 )
I c a n ' t t h i n k o f any, b u t t h i s may be due to my a s s o c ia tio n
w ith the m a t e r i a l s .
(2 2 )
We need to know r e l a t i v e m o istu re r e t e n t i o n and n u t r i e n t values
o f loess caps v s. s u b s o ils formed from igneous p a r e n t m a t e r i a l s .
A ls o , do loess caps c o n ta in enough v o lc a n ic ash to be c l a s s i f i e d
as Andie a t th e subgroup l e v e l ?
76
Table 18.
Code t o Respondents' P o s it io n and L o c a tio n .
Name
P o s it io n
Location
I.
Shelby B ro w n fie ld
S ta te C o rre la to r
SCS5Montana
2.
James Clayton
Research S o il
S c ie n tis t
USFS5Region I
3.
Norman Davis
S o il S c i e n t i s t
USFS5B i t t e r r o o t NF .
4.
Carl Davis
S o il S c i e n t i s t
USFS5G a l l a t i n NF
5.
Maynard Fosberg
P r o f o f S o ils
Univ Idaho,Moscow
6.
June Haigh
S o il S c i e n t i s t
SCS5Madison County
7.
Herb H o ld o r f
S o il S c i e n t i s t
USFS5Lewis & C lark NF
8.
H arold H u n te r*
S o il S c i e n t i s t
SCS,M is so u la County
9.
Lew Keunnen
S o il S c i e n t i s t
USFS5Kootenai NF
10.
Dick K lin e
S o il S c i e n t i s t
USFS5Nez Perce N .F.
11.
C l i n t Mogen+
S ta te C o r r e l a t o r
SCS5Montana
12.
Ron McConnell+
S o il S c i e n t i s t
USFS
13.
Al M artinson
S o il S c i e n t i s t
USFS5F la th e ad NlF
14.
Thomas Nimlos
P r o f o f S o ils
Univ Mont Missoula
15.
Stan Peterson
S o il S c i e n t i s t
USFS5Lolo NF
16.
Roger P o ff
S o il S c i e n t i s t
USFS5Beaverhead NF
17.
E. M. Richlen
S o il S c i e n t i s t
USFS5 Region I
18.
Dave Ruppert
S o il S c i e n t i s t
USFS5 Deer Lodge NF
19.
J . S . Seago*
S o il S c i e n t i s t
SCS5Lake County
20.
N e l l i e S ta r k
P r o f o f S o i ls
Univ Mont Missoula
21.
Gordon W arrington
S o il S c i e n t i s t
USFS5Idaho Panhandle
NF
22.
Dale Wilson
S o il S c i e n t i s t
USFS5C le a rw a te r NF
^ p r e v io u s ly s o i l s c i e n t i s t
+ re tire d s o il s c ie n tis ts
.
.
APPENDIX 2
Pedon D e s c r ip tio n s
Buckhouse
Typic C ryandepts; Medial o v er loamy s k e l e t a l , mixed
Colors a re f o r m oist s o i l
Horizon
unless o th e rw is e i n d ic a t e d
P r o f i l e D e s c r ip tio n
A ll
0 -1 0 cm ( 0 - 4 i n ) Black ( 7 . 5 YR 2 / 2 ) ; stony loam; dark
g ra y is h brown (10 YR 4 / 2 ) i n t e r i o r d ry ; strong f i n e g r a n u la r
s t r u c t u r e ; s o f t , v e r y f r i a b l e , s l i g h t l y s t i c k y , n o n p la s t ic ;
common, r o o t s ; 10% fragments s t r o n g l y a c id pH 5 . 5 ; gradual
wavy boundary.
A12
10-23 cm ( 4 - 9 i n ) very dark brown ( 7 . 5 YR 2 / 2 ) stony loam;
dark g ra y is h brown (10 YR 4 / 2 ) d r y ; strong very f i n e g r a n u la r
s t r u c t u r e ; s o f t , v ery f r i a b l e , s l i g h t l y s t i c k y , n o n p la s t ic ;
common r o o t s ; 20% fragm ents; s l i g h t l y a c id p H - 6 .5 ; gradual
boundary.
A13
23-41 cm ( 9 - 1 6 i n ) v ery dark brown ( 7 . 5 YR 2 / 2 )
dark g ra y is h brown (10 YR 4 / 2 ) d r y ; strong v ery
s t r u c t u r e ; s o f t , v ery f r i a b l e , s l i g h t l y s t i c k y ,
common r o o t s ; 20% fragm ents; medium a c id p H -6 .0
boundary.
A14
4 1 -5 8 cm ( 1 6 -2 3 i n ) v ery dark brown ( 7 . 5 YR 2 / 2 ) stony loam;
dark g ra y is h brown (10 YR 4 / 2 ) e x t e r i o r d r y ; stro n g very f i n e
g r a n u la r s t r u c t u r e ; s o f t , v ery f r i a b l e , s l i g h t l y s t i c k y ,
n o n p l a s t ic ; common r o o t s ; 30% fra gm ents; medium a c id p H -6 .0 ;
gradual wavy boundary.
B 2 1 ir
58-79 cm (2 3 -3 1 i n ) dk. y e l l o w i s h brown (10 YR 3 / 4 ) very stony
l o a m ; I t . y e l l o w i s h brown (10 YR 6 / 4 ) d ry ; weak v ery f i n e
g r a n u la r s t r u c t u r e ; s o f t , v e ry f r i a b l e , s l i g h t l y s t i c k y ,
n o n p l a s t ic ; many f i n e r o o ts ; many f i n e pores; 70% fragm ents;
n e u tr a l p H - 7 .0 ; gradual wavy boundary.
B 2 2 ir
79-97 cm ( 3 1 -3 8 i n ) dk. y e l l o w i s h brown 10 YR 3 / 4 ) very stony
loam; dk. y e llo w is h brown (10 YR 3 / 4 ) d ry ; weak v ery f i n e
g r a n u la r s t r u c t u r e ; s o f t , v e ry f r i a b l e , s l i g h t l y s t i c k y ,
n o n p l a s t ic ; common f i n e r o o t s ; many f i n e pores; 70% fragm ents;
n e u t r a l p H - 7 . 0 ; c l e a r wavy boundary.
stony loam;
f i n e g r a n u la r
n o n p la s t ic ;
gradual
78
Cl
97-12 7 cm (3 8 -5 0 i n ) o l i v e brown ( 2 . 5 Y 4 / 3 ) very stony loam;
p a le brown (10 YR 6 / 3 ) d r y ; weak f i n e g r a n u la r s t r u c t u r e ;
s o f t , v e ry f r i a b l e , n o n s tic k y , n o n p l a s t ic ; few r o o t s ; 85%
fr a g m e n ts ; s t r o n g l y a c id p H - 5 . 5 ; gradual i r r e g u l a r boundary.
C2
127-182 cm (5 0 -7 2 i n ) o l i v e brown ( 2 . 5 Y 4 / 3 ) v ery stony
loam; p a le brown (10 YR 6 / 3 ) d r y ; s o f t , very f r i a b l e , non­
s t i c k y , n o n p l a s t ic ; few f i n e r o o t s ; 85% fra gm e nts ; s tr o n g ly
a c id p H -5.5
V e g e ta tio n :
A b la , Psme, P i a l , Pico p a rk la n d w ith X e t e , Agsu, Cage,
Powh, Acmi and lu p i n e .
L o c a tio n :
3 /1 6 m i. E . , 1 /1 6 m i. N. o f SW c o rn er o f Sec. 3 2 , T18N,
R24W, M issoula C o . , M T ., a p p ro x im a te ly 1 /2 m i. e a s t o f
microwave tow er.
Remarks:
Old Horsehead stony loam.
C o lle c te d Aug. 3 , 1964,
McConnell, Grossman, Lynn, Cawlf i e l d , R ic h le n , Mogen, and
Southard.
Described by M cConnell. S64Mt. 3 2 - 1 .
Unnamed 3
E n tic Cryan depts; Medial over loamy s k e l e t a l , mixed
Colors a re f o r m oist s o i l
Horizon
unless o th e rw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
B21
1 -20 cm ( 0 - 8 i n ) dk. y e llo w is h brown (10 YR 4 / 4 ) s i l t loam;
re d d ish y e l l o w ( 7 . 5 YR 6 / 5 ) crushed d ry ; y e l l o w i s h red
(5 YR 5 / 5 ) crushed; weak, v e ry f i n e , g r a n u la r s t r u c t u r e ;
s o f t , v ery f r i a b l e , n o n s tic k y , n o n p l a s t ic ; many f i n e and
medium r o o t s ; common p o re s , 10% fragm ents; >2 mm; c l e a r
smooth boundary.
B22
20-56 cm (8 - 2 2 i n ) y e l l o w i s h brown (10 YR 5 / 6 ) s i l t loam;
re d d ish y e l l o w ( 7 . 5 YR 6 / 5 ) crushed d r y ; weak, v ery f i n e ,
g r a n u la r s t r u c t u r e ; s o f t , v ery f r i a b l e , n o n s tic k y , n o h p la s tic
common coarse r o o t s ; common t u b u l a r continuous p ores; 15%
fragm ents; a b ru p t i r r e g u l a r boundary.
IIA 2
5 6 -7 4 cm (2 2 -2 9 i n ) o l i v e brown ( 2 . 5 Y 4 / 4 ) g r a v e l l y sandy
loam; I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 3 ) crushed d r y ; l i g h t
79
o l i v e brown ( 2 . 5 Y 5 / 3 ) crushed; weak f i n e and medium;
subangular bloc ky s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e , s l i g h t l y
s t i c k y , s l i g h t l y p l a s t i c ; few f i n e and medium r o o ts ; few
p o re s , common v e s i c u l a r pores; 35% fragm ents; no t reached
wavy boundary.
IIA B .
7 4 -9 4 cm ( 2 9 -3 7 i n ) o l i v e y e l l o w
loam; I t . y e l l o w i s h brown ( 2 . 5 Y
o l i v e brown ( 2 . 5 Y 5 / 3 ) crushed;
s l i g h t l y h a rd , f r i a b l e , s l i g h t l y
few coarse r o o t s ; few pores; 45%
boundary.
II B 2
94-13 5 cm ( 3 7 -5 3 i n ) y e l l o w i s h brown (10 YR 5 / 4 ) g r a v e l l y
loam; y e l l o w i s h brown (10 YR 5 / 4 ) crushed d r y ; l i g h t o l i v e
brown ( 2 . 5 Y 5 / 3 ) crushed; moderate to strong subangular
b locky s t r u c t u r e ; h a rd , f i r m , s t i c k y , p l a s t i c ; few coarse
r o o ts ; few p ores; dk. y e l l o w i s h brown (10 YR 4 / 4 ) c la y skins
on ped fa c e s ; 45% fragm ents; c l e a r wavy boundary.
IIC
135cm ( 5 3 i n ) I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 4 ) sandy
loam; I t . y e llo w is h brown ( 2 . 5 Y 6 / 4 ) crushed d r y ; l i g h t
o l i v e brown ( 2 . 5 Y 5 / 3 ) crushed; moderate to s tro n g sub­
a n g u la r blocky s t r u c t u r e ; h a r d , f i r m , s l i g h t l y s t i c k y ,
s l i g h t l y p l a s t i c ; few r o o t s ; 50% fra g m e n ts .
V e g e ta tio n :
( 2 . 5 Y 6 / 6 ) g r a v e l l y sandy
6 / 4 ) crushed d r y ; l i g h t
weak f i n e subangular blo c k y ;
s tic k y , s lig h t ly p la s tic ;
fragm ents; gradual wavy
Juoc/c.lun
L o c a tio n :
Sec 3 3 , T36N, R33W, L in c o ln C o . , Near Spread C r . , Kooteni
NP.
Remarks:
Sample c o l l e c t e d by Lew Keunnen.
Unnamed 4
E n tic Cryan depts; m e d ia l, mixed
Colors are f o r m o ist s o i l
Horizon
B21
unless oth e rw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
0 -2 3 cm ( 0 - 9 i n ) brown ( 7 . 5 YR 4 / 4 ) crushed; s i l t loam;
brownish y e llo w (10 YR 6 / 6 ) crushed d r y ; brownish y e llo w
(10 YR 6 / 6 ) d r y ; weak v ery f i n e g r a n u la r s t r u c t u r e ; s o f t .
80
v ery f r i a b l e , n o n s tic k y , n o n p l a s t ic ; many f i n e r o o t s ; many
pores; 10% fra gm e nts ; c l e a r smooth boundary.
B22
23-56 cm ( 9 - 2 2 i n ) dk. y e l l o w i s h brown (10 YR 4 / 4 ) crushed;
s i l t loam; brownish y e l l o w (10 YR 6 / 6 ) crushed d r y ; weak,
v ery f i n e g r a n u l a r s t r u c t u r e ; s o f t , v ery f r i a b l e , n o n s tic k y ,
n o n p l a s t ic ; common f i n e & medium r o o t s ; common t u b u l a r
p o re s, many pores; a b ru p t i r r e g u l a r boundary.
V e g e ta tio n :
L o c a tio n :
Remarks:
A b g r /c lu n .
Sec 2 0, T23N, R31W, Sanders C o ., Near White Pine Cr.
Sample c o l l e c t e d by Lew Keunnen.
T r u e f is s u r e
E n tic C ryandepts; medial over l o a m y - s k e l e t a l , mixed
Colors are f o r .moist s o i l unless o th e rw ise i n d i c a t e d
Horizon
P ro file
D e s c r ip tio n
B 2 1 ir
3 -1 3 cm ( 1 . 2 - 5 i n ) reddish brown (5 YR 4 / 4 ) s i l t loam; l i g h t
brown ( 7 . 5 YR 6 / 4 ) d r y ; weak f i n e g r a n u la r s t r u c t u r e ; s o f t ,
v ery f r i a b l e , n o n s tic k y , n o n p l a s t ic ; common ro o ts in c racks;
common v e s i c u l a r p ores; few fragments >2 cm; c l e a r wavy
boundary.
B 2 2 ir
13-25 cm ( 5 - 1 0 i n ) brown ( 7 . 5 YR 4 / 4 ) s i l t loam; I t .
y e l l o w i s h brown (10 YR 6 / 4 ) d r y ; weak f i n e subangular blocky
p a r t i n g to weak f i n e g r a n u la r s t r u c t u r e ; s o f t , very f r i a b l e ,
n o n s tic k y , n o n p l a s t ic ; common f i n e r o o t s ; 5% fragments >2 cm
a b ru p t broken boundary.
B 2 3 ir
25-41 cm (1 0 -1 6 i n ) dark brown ( 7 . 5 YR 3 / 4 ) v e ry g r a v e l l y
f i n e sandy loam; y e l l o w i s h brown (10 YR 5 / 4 ) d r y ; weak f i n e
g r a n u la r s t r u c t u r e ; s l i g h t l y h a r d , very f r i a b l e , n o n s tic k y ,
s l i g h t l y p l a s t i c ; common r o o t s ; few medium p ores; abrupt
boundary.
I I B S l i r 41-61 cm ( 1 6 - 2 4 i n ) s tro n g brown ( 7 . 5 YR 5 / 6 ) v ery g r a v e l l y
v e r y f i n e sandy loam; y e llo w (10. YR 7 / 6 ) d r y ; weak medium
subangular b locky s t r u c t u r e ; s l i g h t l y hard b r i t t l e (5 1 )
very f r i a b l e , n o n s tic k y , n o n p l a s t ic ; many f i n e pores;
81
c l e a r wavy boundary, common v e s i c l e s , few med. pore s,
abundant s k e l e t a n s , common ro o ts between co. f r a g .
30% channers > 3 /4 " .
I I B 3 2 i r 61-91 cm (2 4 -3 6 i n ) brown (10 YR 5 / 3 ) very g r a v e l l y f i n e
sandy loam; v ery p a le brown (10 YR 7 / 4 ) d r y ; v ery weak
v ery f i n e g r a n u la r s t r u c t u r e ; v ery f r i a b l e , s l i g h t l y s t i c k y ,
s l i g h t l y p l a s t i c ; c l e a r wavy boundary; 50% channer > 3 /4 "
c l e a r and s ta in e d s k e le t a n s .
I I B 3 3 i r 9 1-1 1 2 cm (3 6 - 4 4 i n )
y e l l o w i s h brown (10
f r i a b l e , n o n s tic k y ,
80% g ra v e l channers
V e g e ta tio n :
y e l l o w i s h brown (10 y r 5 / 6 ) sandy loam;
YR 5 / 6 ) d r y ; s in g le g r a i n , s o f t , very
n o n p l a s t ic ; c l e a r i r r e g u l a r boundary,
> 3 /4 "
few r o o ts .
P i e n , A b la , Pimo, Laoc, P ic o , Psme, X e t e , V a g i, Mefe.
L o c a tio n :
Wishard Cr. a r e a , 8 . 9 mi from US #10, a t Haugen on Middle
Fork Big Creek Rd. Turn r i g h t and cross Wishard Cr and
proceed 3 .3 m i.
P i t is to r i g h t o f road when t r a v e l i n g w e s t.
M in e ral County.
Remarks:
Sample c o l l e c t e d by M u e l l e r , Thomas, Grossman,. Lyman,
R ic h le n , Mogan and Southard.
Wishard S i l t Loam
Aquic C r y o b o r o lls ; I q a m y - s k e l e t a l , mixed
Colors a re f o r m o ist s o i l
Horizon
unless o th e rw is e i n d ic a t e d
P r o f i l e D e s c r ip tio n
A ll
0 - 5 cm ( 0 - 2 i n ) v ery dark brown ( 7 . 5 YR 1 /2 ) s i l t loam;
v dk g ra y is h brown (10 YR 3 / 2 ) d r y ; weak f i n e & medium
g r a n u la r s t r u c t u r e ; s o f t , v ery f r i a b l e , n o n s tic k y , n o n p la s t ic ;
common r o o t s ; common pores; few fragm ents; c l e a r boundary.
A12
5 -1 8 cm ( 2 - 7 i n ) v ery dark brown ( 7 . 5 YR 1 /2 ) s i l t loam;
brown (10 YR 4 / 3 ) d r y ; s tro n g f i n e subangular blocky and .
moderate f i n e g r a n u la r s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e , .
n o n s tic k y , n o n p l a s t ic ; common r o o t s ; few f i n e p ores; s k e le t a n s ;
s l i g h t l y a c id p H - 6 .2 .
82
A13
18-30 cm ( 7 - 1 2 i n ) v ery dark brown ( 7 . 5 YR 2 / 4 ) s i l t loam;
brown ( 7 . 5 y r 5 / 3 ) d r y ; weak f i n e g r a n u la r s t r u c t u r e ;
s l i g h t l y h a rd , f r i a b l e , n o n s tic k y , n o n p l a s t ic ; common ro o ts ;
s k e le t a n s ; 10% fragments >2 cm; gradual boundary.
B 2 1 ir
30-51 cm (1 2 -2 0 i n ) dark brown ( 7 . 5 YR 3 / 4 ) s i l t loam; I t .
y e llo w is h brown (10 YR 6 / 4 ) d r y ; moderate f i n e & medium
g r a n u l a r s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e , s l i g h t l y s t i c k y ,
s l i g h t l y p l a s t i c ; common r o o t s ; common medium p o re s , many
f i n e p ores; many s k e le t a n s ; c l e a r i r r e g u l a r boundary.
B 2 2 ir
51-79 cm (2 0 -3 1 i n ) y e l l o w i s h brown (10 YR 5 / 6 ) g r a v e l l y
loam; v ery p a le brown (10 y r 7 / 4 ) d r y ; massive s t r u c t u r e ;
s l i g h t l y h a rd , v e ry f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y
p l a s t i c ; few r o o t s ; many s k e l e t a n s ; 25% fr a g m e n ts , 10%
fragments >25 cm; gradual boundary.
IIC l
117-157 cm ( 4 6 -6 2 i n ) y e l l o w i s h brown (10 YR 5 / 6 ) very
g r a v e l l y loam; p a le y e l l o w ( 2 . 5 Y 7 / 4 ) d r y ; massive s t r u c t u r e
h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; few ro o ts ;
40% fragments >2 cm; c l e a r boundary.
IIC 2
157-193 cm ( 6 2 -7 6 i n ) I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 3 ) very
g r a v e l l y sandy loam; l i g h t gray ( 2 . 5 Y 7 / 2 ) d r y ; massive
s t r u c t u r e ; s k e le ta n s on upper s u rfa c e s o f peds; c l e a r
boundary.
V e g e ta tio n :
Juoc, P i e n , A c a r , Rupa1 V eca, A l s i , Caro and
Ac gl .
.
.
L o c a tio n :
On Moore Cr. Rd. 9 . 5 m ile s from U.S. Highway 1 0, 2 .2
m ile s p a s t j u n c t i o n w ith South Fork L i t t l e Joe Cr. Rd.,
M in e ra l County.
Felan
Andie C ry o c h re p ts ; l o a m y - s k e l e t a l , mixed
Colors a re f o r m oist s o i l
Horizon
unless o therw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
01
8 - 5 cm ( 3 - 2 i n ) f o r e s t l i t t e r undecomposed.
02
5 -0 cm ( 2 - 0 i n ) b la c k h i g h l y decomposed f o r e s t l i t t e r .
83
A2
0 - 8 cm ( 0 - 3 i n ) g ra y is h brown (10 YR 5 / 2 ) ; s i l t loam; l i g h t
gray (10 YR 7 / 2 ) d r y ; stro n g f i n e g r a n u la r ; s o f t , very
f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; many v ery f i n e
to coarse r o o t s ; many v ery f i n e and f i n e i n t e r s t i t i a l pores;
p H - 5 .6 ; c l e a r u n d u la tin g boundary.
B2
8 -2 0 cm ( 3 - 8 i n ) stro n g brown ( 7 . 5 YR 5 / 6 ) v e ry f i n e sandy
loam; re d d ish y e llo w ( 7 . 5 YR 7 / 5 ) d r y ; s o f t , v ery f r i a b l e ,
n o n s tic k y , n o n p l a s t ic ; many f i n e r o o t s ; many f i n e void
i n t e r s t i t i a l pores; medium a c id p H - 5 .6 ; c l e a r wavy boundary.
IIA21b
2 0 -3 8 cm ( 8 - 1 5 i n ) I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 3 ) g r a v e l l y
loam; w h ite ( 2 . 5 Y 8 / 2 ) d r y ; massive s t r u c t u r e ; s l i g h t l y
h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; many f i n e
r o o t s ; many f i n e pores, many void i n t e r s t i t i a l pores; 45%
fr a g m e n ts ; medium a c id p H -5 .8 ; c l e a r smooth boundary.
IIA 22b
3 8 -5 8 cm (1 5 -2 3 i n ) I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 4 ) g r a v e l l y
loam; p a le y e llo w ( 2 . 5 Y 7 / 3 ) d r y ; massive s t r u c t u r e ;
s l i g h t l y h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ;
many f i n e r o o t s ; many f i n e p o re s , many void i n t e r s t i t i a l
pores; 45% fra g m e n ts ; medium a c id p H - 5 .8 ; d i f f u s e boundary.
IIA23b
5 8 -8 4 cm (2 3 -3 3 i n ) I t . y e l l o w i s h brown ( 2 . 5 Y 6 / 4 ) g r a v e l l y
loam; p a le y e llo w ( 2 . 5 Y 7 / 4 ) d r y ; massive s t r u c t u r e ;
s l i g h t l y h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ;
many f i n e r o o t s ; many f i n e p o re s , may void i n t e r s t i t i a l
p o re s; 40% fr a g m e n ts ; n e u t r a l p H -7 .0 .
IIB 2 1 t
8 4 -1 2 4 cm (3 3 -4 9 i n ) l i g h t o l i v e brown ( 2 . 5 Y 5 / 4 ) g r a v e l l y
c la y loam; o l i v e y e llo w ( 2 . 5 Y 6 / 5 ) d r y ; massive s t r u c t u r e ;
s l i g h t l y h a rd , f r i a b l e , s t i c k y , p l a s t i c ; common f i n e r o o t s ;
many f i n e p o re s , many void i n t e r s t i t i a l pores; 40% fra g m e n ts ;
m i l d l y a l k a l i n e p H -7 .6 ; gradual smooth boundary.
IIB 2 2 t
124-152 cm (4 9 -6 0 i n ) l i g h t o l i v e brown ( 2 . 5 Y 5 / 4 ) g r a v e l l y
c la y loam; p a le y e l l o w ( 2 . 5 Y 7 / 4 ) d ry ; massive s t r u c t u r e ;
s l i g h t l y h a r d , f r i a b l e , s t i c k y , p l a s t i c ; few f i n e ro o ts ;
many f i n e p o re s , many void i n t e r s t i t i a l p o re s ; 40% fragm ents;
m o d e rately a l k a l i n e p H - 8 .2 ; c l e a r wavy boundary.
V e g e ta tio n :
P i e n , Psme, V a g i, Pamy, and Chum.
L o c atio n :
1500 f t N, 1500 f t W o f SE c o rn e r Sect 18 T15N, R16W,
. M issoula County.
84
Remarks:
Described by: J. P u rc e ll, H. Hunter, C. Mogeh, K. Flack,
July 22, 1970. S70Mt 32-2
Holloway
Andie C ry o c h re p ts ; l o a m y - s k e l e t a l , mixed
Colors a re f o r m oist s o i l
Horizon
unless o th e rw is e in d ic a te d
P r o f i l e D e s c r ip tio n
01
7 -5 cm ( 3 - 2 i n )
02
5 -0 cm ( 2 - 0 i n )
A2
0 - 5 cm ( 0 - 2 i n ) dark g ra y is h brown (10 YR 4 / 2 ) ; s i l t loam;
l i g h t brownish gray (10 YR 6 / 2 ) d r y ; moderate f i n e and very
f i n e g r a n u l a r ; s o f t , v ery f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y
p l a s t i c ; many f i n e to coarse r o o t s , many f i n e t o v ery f i n e
p ore s; 10% coarse fragm ents; p H - 5 .4 ; ab ru p t wavy boundary.
B2
5 -25 cm ( 2 - 1 0 i n ) dark brown (10 YR 3 / 3 ) g r a v e l l y s i l t loam;
y e l l o w i s h brown (1 0 YR 5 / 4 ) d r y ; v ery weak v ery f i n e crumb
s t r u c t u r e ; s o f t , v ery f r i a b l e , n o n s tic k y , n o n p l a s t ic ; f i n e
r o o t s ; many f i n e p o re s, many pores; 25% fr a g m e n ts ; medium
a c id p H - 5 .6 ; a b ru p t wavy boundary.
IIA 2 1
25-81 cm (1 0 -3 2 i n ) l i g h t brown ( 7 . 5 YR 6 / 3 ) v e ry g r a v e l l y
f i n e sandy loam; p in k is h gray ( 7 . 5 YR 7 / 2 ) d r y ; massive
s t r u c t u r e ; h a r d , f r i a b l e , n o n s tic k y , n o n p l a s t ic ; many f i n e
r o o t s ; many f i n e p o r e s ; 60% fra g m e n ts ; s t r o n g l y a c id p H -5 .4 ;
gradual smooth boundary.
IIA 2 2
8 1-1 4 0 cm ( 3 2 -5 5 i n ) l i g h t brown ( 7 . 5 YR 6 / 4 ) v ery g r a v e l l y
loam; pink ( 7 . 5 YR 7 / 3 ) d r y ; massive s t r u c t u r e ; h a rd , f r i a b l e ,
n o n s tic k y , n o n p l a s t ic ; many f i n e r o o ts ; many f i n e pores; 65%
fra g m e n ts ; medium a c id p H - 5 . 6 ; gradual smooth boundary.
IIC l
140-157 cm (5 5 -6 2 i n ) brown ( 7 . 5 YR 5 / 3 ) v ery g r a v e l l y f i n e
sandy loam; p in k is h w h ite ( 7 . 5 YR 8 / 2 ) d r y ; massive s t r u c t u r e ;
h a rd , f r i a b l e , n o n s tic k y , n o n p l a s t ic ; few f i n e r o o t s ; many
f i n e p ore s; 70% fra gm e nts ; medium a c id p H -5 .8 .
V e g e ta tio n :
Laoc, Psme, P ic o , X e t e , V a g i , Chum and Cage.
85
L o c atio n :
2400 f t W, 800 f t S o f NE c o rn e r Sec 11, T14N, R17W,
Missoula County.
Remarks:
Described by:
J. P u r c e l l , H. H u n te r, C. Mogen, K. F la c k ,
J u ly 2 8 , 1970.
S70Mt 3 2 -6 .
S pring Emery
Andie C ry ochrepts; coarseloamy over sandy s k e l e t a l ,
mi xed
Colors a re f o r m o ist s o i l
Horizon
unless o th e rw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
B21
0 -1 5 cm ( 0 - 6 i n ) brown (10 YR 4 / 3 ) g r a v e l l y s i l t loam; dark
g ra y is h brown (10 YR 4 / 2 ) d r y ; weak medium to coarse crumb;
s o f t , very f r i a b l e , n o n s tic k y , n o n p la s t ic ; common f i n e &
medium r o o t s ; 30% fragm ents; gradual wavy boundary.
B 2 2 ir
15-23 cm ( 6 - 9 ) l i g h t o l i v e brown ( 2 . 5 Y 5 / 4 ) crushed; very
g r a v e l l y s i l t loam; p a le y e l l o w ( 2 . 5 Y 7 / 3 ) crushed d r y ;
weak medium subangular blocky s t r u c t u r e ; s l i g h t l y h a rd ,
f r i a b l e , n o n s tic k y , n o n p l a s t ic ; common f i n e & medium r o o ts ;
60 to 70% fra gm e nts ; a b ru p t i r r e g u l a r boundary.
IIA 2
2 3 -5 8 cm ( 9 - 2 3 i n ) l i g h t o l i v e brown ( 2 . 5 Y 5 / 3 ) crushed;
v e ry g r a v e l l y sandy loam; p a le y e l l o w ( 2 . 5 Y 7 / 3 ) crushed
d r y ; massive s t r u c t u r e ; lo o s e , f r i a b l e , n o n s tic k y , n o n p la s t ic ;
65% fra gm e nts ; not reached boundary.
V e g e ta tio n :
A b la /M e fe .
L o c atio n :
SW 1 / 4 , NE 1 / 4 , Sec 2 7 , T7N, R8W, Powell County.
S pring Creek-Emery Road.
86
S u g a rlo a f I
Andie C ry o c h re p ts ; coarse loamy, mixed
Colors a re f o r m oist s o i l
Horizon
unless o th e rw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
01
3 -0 cm ( 1 - 0 i n ) decomposed f o r e s t l i t t e r .
02
3 -0 cm ( 1 - 0 i n ) decomposed f o r e s t l i t t e r .
821
0 -1 8 cm ( 0 - 7 i n ) brown (1 0 YR 4 / 3 ) crushed; g r a v e l l y s i l t
loam; p a le brown (10 YR 6 / 3 ) crushed d r y ; weak medium
subangular blocky s t r u c t u r e ; s o f t , very f r i a b l e , s l i g h t l y
s t i c k y , s l i g h t l y p l a s t i c ; many f i n e & medium r o o t s ; 30%
fra g m e n ts , 5% fragments >25 cm; gradual smooth boundary.
IIB 2 2
18-38 cm ( 7 - 1 5 i n ) brown (10 YR 5 / 3 ) crushed; v e ry g r a v e l l y
loam; l i g h t gray (10 YR 7 / 2 ) crushed d r y ; h a r d , f i r m ,
s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; few r o o t s ; not reached
boundary.
V e g e ta tio n :
L o c atio n :
Remarks:
A b la , A l s i , Vase,
SW 1 / 4 , NW 1 / 4 , Sec 6 , T7N, R7W, Powell County.
Sample c o l l e c t e d on S u g a r lo a f Mountain, October 2 9 , .1975.
E lk n e r V a r i a n t 2
Andie C ry o c h re p ts ; c o a rs e -lo a m y , mixed
.
Colors a re f o r m o ist s o i l unless o th e rw ise i n d i c a t e d
Horizon
P ro file
D e s c r ip tio n
B 2 ir
10-28 cm (4 -1 1 i n ) brown (10 YR 4 / 3 ) crushed; s i l t loam;
I t . y e l l o w i s h brown (10 YR 6 / 4 ) crushed d r y ; v e r y weak
medium a n g u la r blocky s t r u c t u r e ; s o f t , very f r i a b l e , s l i g h t l y
s t i c k y , n o n p l a s t ic ; common r o o t s ; 5% fragm ents; abrupt
boundary.
IIB 3
28-53 cm (1 1 -2 1 i n ) p a le brown (10 YR 6 / 3 ) crushed; f i n e
g r a v e l l y sandy loam; w h ite (10. YR 8 / 2 ) crushed d r y ; massive
s t r u c t u r e ; h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ;
40% fra gm ents; not reached boundary.
87
V e g e ta tio n :
A bla , P i e n , A l s i , and Caca.
Location: Photo Point 1273-45-2, about 6.5 miles south o f Skalkaho
Pass, Granite County.
Remarks:
Sample c o l l e c t e d w ith Dave Ruppert.
C a b in et
A n d e p tic C ry o b o ra lf s ; medial over c la y e y , mixed
Colors a r e f o r m o is t s o i l unless o th e rw is e i n d i c a t e d
Horizon
P r o f i l e D e s c r ip tio n
B 2 ir
2 -2 8 cm (1 -1 1 i n ) s tro n g brown ( 7 . 5 YR 4 / 5 ) crushed; s i l t
loam; very p a le brown (10 YR 7 / 4 ) crushed d r y ; weak f i n e
subangular blocky s t r u c t u r e ; lo o s e , very f r i a b l e , n o n s tic k y ,
n o n p l a s t ic ; many f i n e r o o t s ; f i r m f i n e iron-manganese
c o n c r e tio n s ; a b ru p t smooth boundary.
IIA 2
28-41 cm (1 1 -1 6 i n ) p a le brown (10 YR 6 / 3 ) s i l t loam; w h ite
(10 YR 8 / 2 ) d r y ; massive p a r t i n g to moderate medium a n g u lar
blocky s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e , s l i g h t l y s t i c k y ,
p l a s t i c ; few f i n e r o o t s ; few f i n e t u b u l a r p ores; 2% fragments
gradual wavy boundary.
IIB 2 +
4 1 -7 9 cm (1 6 -3 1 i n ) pink ( 7 . 5 YR 7 / 4 ) crushed; s i l t y c la y ;
few f i n e & medium m o t t le s ; stro n g medium & coarse a ngular
blocky s t r u c t u r e ; v ery h a r d , f i r m , s t i c k y , p l a s t i c ; d i s t i n c t
l i g h t re d d ish brown (5 YR 6 / 3 ) c la y s k i n s ; 1% fragm ents;
gradual i r r e g u l a r boundary.
V e g e ta tio n :
Juoc, A bgr, Laoc, Pimo, P o t r , S y a l , Rose Sp^ L i bo.
L o c atio n :
100 f t N and 100 f t W o f i n t e r s e c t i o n Highway 200 and
Noxon Rapids Dam Road.
Remarks:
Nimlos 1964 study s i t e Sanders County.
88
Krause
Andie U s to c h re p t; loamy s k e l e t a l , mixed, f r i g i d
Colors a re f o r m oist s o i l
Horizon
unless o th e rw is e in d ic a t e d
P r o f i l e D e s c r ip tio n
B21
3 -2 5 cm ( 1 - 1 0 i n ) brown ( 7 . 5 YR 4 / 4 ) very g r a v e l l y sandy
loam; l i g h t brown ( 7 . 5 YR 6 / 4 ) d r y ; weak f i n e crumb s t r u c t u r e
s o f t , f r i a b l e , n o n s tic k y n o n p l a s t ic ; common, f i n e & medium
r o o t s ; 70% fra g m e n ts .
IIA&B
25-61 cm ( 1 0 - 2 4 i n ) p in k ( 7 . 5 YR 7 / 4 ) v e r y g r a v e l l y sandy
loam; v ery p a le brown (10 YR 8 / 4 ) d r y ; weak f i n e subangular
b lo c ky s t r u c t u r e ; s l i g h t l y h a r d , f r i a b l e , s l i g h t l y s t i c k y ,
n o n p l a s t ic ; >60% coarse fr a g m e n ts .
V e g e ta tio n :
Thoc, Laoc, P i en, A bla , Psme, A c g l , Mare, S y a l , Rupa,
V a g i , Pamy and Libo
L o c atio n :
Remarks:
NW 1 / 4 , SW 1 /4 Sec I ,
T30N, R19W, F lathead County.
Coram # 1 2 ( 1 9 ) .
E lk n e r V a r i a n t I
Andie C ry o c h re p ts ; coars e -lo am y , mixed
Colors a r e f o r m o ist s o i l
Horizon
unless o th e rw ise i n d ic a t e d
P r o f i l e D e s c r ip tio n
B 2 ir
0 -1 8 cm ( 0 - 7 i n ) dk. y e l l o w i s h brown (10 YR 3 / 4 ) crushed;
f i n e g r a v e l l y sandy loam; y e l l o w i s h brown (1 0 YR 5 / 4 )
crushed d r y ; weak medium subangular blocky s t r u c t u r e ; s o f t ,
very f r i a b l e , n o n s tic k y , n o n p l a s t ic ; common r o o t s ; 20%
fragments >2 mm; gradual boundary.
IIB 3
17-28 cm (7 -1 1 i n ) brown (10 YR 5 / 3 ) crushed; g r a v e l l y loamy
sand; v ery p a le brown (10 YR 7 / 3 ) crushed d r y ; massive
s t r u c t u r e ; s o f t , lo o s e , s l i g h t l y s t i c k y , n o n p l a s t ic ; few
r o o t s ; 45% fr a g m e n ts ; not reached boundary.
V e g e ta tio n :
A b la /V a s c.
89
Location: Photo Point 1273-45-1, about 6 m ile s .S o f Skalkaho Pass,
Granite County.
Remarks:
Sample c o l l e c t e d w it h Dave Ruppert.
Unnamed 5
F l u v e n t ic E u tr o c h r e p t s ; coarse loamy, mixed a cid
Colors are f o r m o ist s o i l
Horizon
unless o th e rw ise i n d i c a t e d
P r o f i l e D e s c r ip tio n
Al
0 - 5 cm ( 0 - 2 i n ) brown ( 7 . 5 YR 4 / 4 ) s i l t loam; moderate f i n e
crumb s t r u c t u r e ; many r o o t s ; medium a c id p H - 5 .8 ; a b rupt smooth,
boundary.
B21
5 -1 3 cm ( 2 - 5 i n ) dk. y e l l o w i s h brown (10 YR 4 / 4 ) s i l t loam;
brown ( 7 . 5 YR 4 / 4 ) ; weak medium g r a n u la r s t r u c t u r e ; many
r o o t s ; many f i n e pores; common f a i n t cutans o f unknown type
i n r o o t channels a n d /o r pores; s l i g h t l y a c id p H - 6 .2 ; abrupt
smooth boundary.
B31
13-23 cm ( 5 - 9 i n ) brown (10 YR 5 / 3 ) crushed; sandy loam;
brown (10 YR 5 / 3 ) crushed d r y ; weak subangular blocky
s t r u c t u r e ; common r o o t s ; common f i n e pores; many bla ck
(10 YR 2 / 1 ) o rg a n ic c u ta n s , brown ( 7 . 5 YR 4 / 4 ) org a n ic cutans;
s l i g h t l y a c id p H - 6 .4 ; c l e a r smooth boundary.
B32
23-51 cm (9 - 2 0 i n ) y e l l o w i s h brown (10 YR 5 / 4 ) sandy loam;
massive s t r u c t u r e ; common f i n e pores; common da rk brown
( 7 . 5 YR 3 / 2 ) o rg a n ic cuta n s; s l i g h t l y a c id p H -6 .4 c l e a r
smooth boundary.
B33
5 1 -6 4 cm (2 0 -2 5 i n ) brown (1 0 YR 5 / 3 ) sandy loam; massive .
s t r u c t u r e ; few r o o t s ; few t u b u l a r pores; few dark brown
( 7 . 5 YR 3 / 2 ) org a n ic cutans in r o o t channels a n d /o r pores;
n e u tr a l p H - 7 .0 ; abrupt wavy boundary.
IIA 21b
64-71 cm ( 2 5 - 2 8 i n ) p a le brown (10 YR 6 / 3 ) sandy loam;
weak medium p l a t y s t r u c t u r e ; few r o o t s ; common coarse t u b u l a r
p o re s , common v e s i c u l a r pores; y e llo w is h brown (10 YR 5 /4 )
cutans o f unknown type i n r o o t channels a n d /o r pores I t .
y e l l o w i s h brown (10 YR 6 / 4 ) cutans o f unknown type on h o riz o n ta l
ped fa c e s ; n e u tr a l p H - 7 .0 ; a b ru p t smooth boundary.
;
'
90
IIB 22b
7 6 -8 4 cm (3 0 -3 3 i n ) brown (10 YR 5 / 3 ) s i l t loam; weak coarse
subangular bloc ky s t r u c t u r e ; s o f t , f r i a b l e , s t i c k y , s l i g h t l y
p l a s t i c ; few f i n e t u b u l a r p o re s, few f i n e v e s i c u l a r pores;
few f a i n t w h ite (10 YR 8 / 2 ) calcium carbonate c u ta n s ,
g ra y is h brown (1 0 YR 5 / 2 ) cutans o f unknown type on v e r t i c a l
ped f a c e s , g ra y is h brown (10 YR 5 / 2 ) cutans o f unknown type
in r o o t channels a n d /o r pores; m i l d l y e f f e r v e s c e n t ;
m o d e rately a l k a l i n e p H - 8 .2 ; c l e a r smooth boundary.
ilB 31 b
8 4-1 1 2 cm ( 3 3 -4 4 i n ) g ra y is h brown ( 2 . 5 Y 5 / 2 ) s i l t loam;
massive s t r u c t u r e ; s o f t , f r i a b l e , s t i c k y , s l i g h t l y p l a s t i c ;
few f i n e v e s i c u l a r p o re s , few f i n e t u b u l a r p ores; few dk.
y e l l o w i s h brown (10 YR 4 / 4 ) cutans o f unknown type in r o o t
channels a n d /o r pores; few f i n e iron-manganese c o n c re tio n s ;
m i l d l y e f f e r v e s c e n t ; m ode rately a l k a l i n e p H -8 .2 .
V e g e ta tio n :
Laocs Vasc, A ruv, Caru.
L o c a tio n :
415 f t E, 480 f t S o f NW c o rn e r o f Sec 8 , T29N, R26W
L in c o ln County.
S u g a rlo a f 2
Andie C ry o c h re p ts ; coarse loamy, mixed
Colors a re f o r m o ist s o i l
Horizon
unless o th e rw is e i n d i c a t e d
P r o f i l e D e s c r ip tio n
01
2 -0 cm ( 2 - 0 i n ) decomposed f o r e s t l i t t e r .
02
2 - 0 cm ( 1 - 0 i n ) decomposed f o r e s t l i t t e r .
B2
0 -2 0 cm ( 0 - 8 i n ) dark g ra y is h brown (10 YR 4 / 2 ) crushed;
g r a v e l l y sandy loam; l i g h t brownish gray (10 YR 6 / 2 ) crushed
d r y ; weak medium subangular b locky s t r u c t u r e ; s l i g h t l y hard,
f r i a b l e ; s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; common f i n e r o o t s ;
gradual smooth boundary.
B3
20cm (8 - 1 5 i n ) g ra y is h brown (10 YR 5 / 2 ) crushed; very
g r a v e l l y loam; l i g h t brownish gray (10 YR 6 / 2 ) crushed d ry ;
h a rd , f i r m , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; few r o o ts ;
45% fra g m e n ts ; gradual smooth boundary.
91
V e g e ta tio n :
Location:
Remarks:
A b la , Psme, Aruv.
SW 1 /4 , NE 1 /4 , Sec I , T7N, R8W, Powell County.
Sample c o l l e c t e d on S u g a rlo a f Mountain e a s t o f Deer Lodge
on October 2 9 , 1976.
H il g a r d
L i t h i c C r y o r t h e n t , . f i n e loamy, m ixed, shallow
Colors a re f o r m o ist s o i l
Horizon
B 2 ir
P r o f i l e D e s c r ip tio n
0 -2 0 cm ( 0 - 8 i n ) brown (10 YR 4 / 3 ) crushed; s i l t loam;
brown (10 YR 5 / 3 ) crushed d r y ; s l i g h t l y h a rd , f r i a b l e ,
s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; few fragm ents; abrupt
boundary.
V e g e ta tio n :
L o c a tio n :
Remarks:
A lp in e t u r f .
N 1 /2 Sec 11, TlO S, R2E, G a l l a t i n County.
Sample c o l l e c t e d by Carl D a v is .
Holloway V a r i a n t
T y p ic C ry o c h rep ts; l o a m y - s k e l e t a l , mixed
Colors are f o r m o is t s o i l
Horizon
unless o th e rw is e i n d ic a t e d
unless o th e rw is e in d ic a t e d
P r o f i l e D e s c r ip tio n
A2
2 -1 3 cm ( 1 - 5 i n ) brown ( 7 . 5 YR 4 / 2 ) loam; p in k is h gray ( 7 . 5 .
YR 6 / 2 ) d r y ; lo o s e , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y
p l a s t i c ; 5% fragm ents.
B 2 ir
13-33 cm (5 - 1 3 i n ) strong brown ( 7 . 5 YR 4 / 5 ) crushed; sandy
loam; r e d d is h y e l l o w ( 7 . 5 YR 6 / 5 ) crushed d r y ; weak f i n e
subangular blocky s t r u c t u r e ; lo o s e , f r i a b l e , s l i g h t l y s t i c k y ,
s l i g h t l y p l a s t i c ; gradual boundary.
92
IIB 3 1
IIB 3 2
13-61 cm (5 - 2 4 i n ) brown ( 7 . 5 YR 5 / 4 ) c rushe d; g r a v e l l y
sandy loam; very p a le brown (1 0 YR 7 / 4 ) crushed d r y ; massive
s t r u c t u r e ; s o f t ^ very f r i a b l e , n o n s tic k y , n o n p la s t ic ;
gradual boundary.
61-97 cm (2 4 -3 8 i n ) brownish y e llo w (10 YR 6 / 5 ) crushed;
g r a v e l l y sandy loam; v ery p a le brown (10 YR 7 / 4 ) crushed
:d r y ; massive s t r u c t u r e ; lo o s e , f r i a b l e , n o n s tic k y , n o n p la s t ic .
V e g e ta tio n :
L o c atio n :
Remarks:
A b la /X e te .
NW1/4, NW1/4, NW1/4, Sec. 3 6 , T2S, R19W, Beaverhead County.
Sample c o l l e c t e d w it h Roger P o f f .
E lk n e r Sandy Loam
Typic C ry o c h re p ts ; c o a rs e -lo am y , mixed
Colors a re f o r m o ist s o i l unless oth e rw ise i n d i c a t e d
Horizon
P r o f i l e D e s c r ip tio n
Al
0 -3 cm ( 0 - 1 i n ) b la c k (1 0 YR 2 / 1 ) sandy loam; dark g ra yis h
brown (10 YR 4 / 2 ) d r y ; moderate medium g r a n u la r s tru c tu re ;many r o o t s ; a b ru p t wavy boundary.
B2
3 -1 5 cm ( 1 - 6 i n ) brown (1 0 YR 5 / 3 ) sandy loam; T i g h t gray
(10 YR 7 / 2 ) d r y ; moderate to s tro n g medium g r a n u la r s t r u c t u r e ;
s o f t , f r i a b l e , n o n s tic k y , n o n p l a s t ic ; many f i n e r o o t s ; f a i n t
s k e le ta n s on sand and g r a v e l ; c l e a r wavy boundary.
B31
15-30 cm (6 -1 2 i n ) p a le brown (10 YR 6 / 3 ) sandy loam; l i g h t
gray (10 YR 7 / 2 ) d r y ; weak coarse subangular blocky s t r u c t u r e ;
s o f t , v e ry f r i a b l e , n o n s tic k y , n o n p la s t ic ; common r o o ts ; few
f i n e pores; y e l l o w i s h brown (10 YR 5 /4 ) s k e le ta n s on sand and
g r a v e l ; 5% fragments > 2 . cm; gradual wavy boundary.
B32
3 0 -4 6 cm (1 2 -1 8 i n ) p ale brown (10 YR 6 / 3 ) sandy, loam; l i g h t
gray (1 0 YR 7 / 2 ) d r y ; massive s t r u c t u r e ; few f i n e r o o ts ;
y e l l o w i s h brown (10 YR 5 / 4 ) s k e le ta n s on sand and g r a v e l ;
ab ru p t wavy boundary.
93
Cl
4 6 -10 7 cm (1 8 -4 2 i n ) l i g h t gray (10 YR 6 / 1 ) loamy sand;
l i g h t gray (10 YR 7 / 1 ) d r y ; weak, f i n e crumb s t r u c t u r e ; lo o s e ,
v ery f r i a b l e , n o n s tic k y , n o n p l a s t ic ; few r o o t s ; c l e a r i r r e g u l a r
boundary.
V e g e ta tio n :
L o c a tio n :
Remarks:
A b la , Psme, Pico
o rig in a lly ;
now Pipo P l a n t a t i o n .
Near Sec 2 5 , T3N, R19W, R a v a l l i County, Near Rye Cr.
Rye Creek No. I — Ponderosa Pine Improvement Study
S74Mt 8 1 - 1 .
From the S le e p in g C h ild Burn.
Unnamed 2
Typic C r y o r t h e n t s ; mixed
Colors a re f o r m o is t s o i l
Horizon
unless o th e rw ise in d ic a t e d
P r o f i l e D e s c r ip tio n
82
0 -1 5 cm ( 0 - 6 i n ) brown ( 7 . 5 YR 4 / 2 ) s i l t loam; l i g h t brownish
gra y (10 YR 6 / 2 ) d r y ; weak medium a n g u la r bloc ky p a r t i n g to
moderate medium g r a n u la r s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e ,
1
n o n s tic k y , n o n p l a s t ic ; 5% fr a g m e n ts ; a b ru p t wavy boundary.
IIC l
15-73 cm ( 6 - 2 9 i n ) g ra y is h brown ( 2 . 5 Y 5 / 2 ) loam; I t . .
y e l l o w i s h brown ( 2 . 5 Y 6 / 3 ) d r y ; weak medium a n g u la r blocky
p a r t i n g to weak medium g r a n u l a r s t r u c t u r e ; s l i g h t l y hard,
f r i a b l e , n o n s tic k y , n o n p l a s t ic ; 40% fra gm e nts ; c l e a r smooth
boundary.
IIIC 2
73-101 cm (2 9 -4 0 i n ) l i g h t o l i v e brown ( 2 . 5 Y 5 / 3 ) s i l t y
c la y loam; l i g h t brownish gray ( 2 . 5 Y 6 / 2 ) d r y ; weak medium
a n g u la r blocky s t r u c t u r e ; h a r d , f r i a b l e , s t i c k y , p l a s t i c ;
20% fra g m e n ts ; m oderately e f f e r v e s c e n t (H C L); c l e a r wavy
boundary.
V e g e ta tio n :
Abla and P i en.
L o c a tio n :
SW 1 / 4 , SE 1 / 4 , Sec 10, T6N, RlOE, Meagher County, near
West Fork Cottonwood Creek.
Remarks:
Sample c o l l e c t e d by Herb H o l d o r f .
94
Unnamed I
T ypic C ry o c h re p ts ; f i n e s i l t y , mixed
Colors a re f o r m oist s o i l unless o th e rw is e i n d i c a t e d
Horizon
P r o f i l e D e s c r ip tio n
B2
0 -1 5 cm ( 0 - 6 i n ) brown ( 7 . 5 YR 4 / 4 ) s i l t y c la y lo a m ; ' l i g h t
brown ( 7 . 5 YR 6 / 3 ) d ry ; weak medium a n g u la r blocky p a r tin g
to moderate f i n e g r a n u l a r s t r u c t u r e ; s l i g h t l y h a rd , f r i a b l e
s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; 15% lim estone fragm ents;
noncalcareous (H C L); a b ru p t wavy boundary.
II B 2
15-100 CM ( 6 - 3 9 i n ) brown ( 7 . 5 YR 5 / 4 ) c la y loam; l i g h t
brown ( 7 . 5 YR 6 / 3 ) d r y ; moderate medium a n g u la r blocky
p a r t i n g to moderate f i n e a n g u la r blocky s t r u c t u r e ; s l i g h t l y
h a rd , f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; 60%
lim es to n e fra gm e nts ; m o d e rately e f f e r v e s c e n t ; c l e a r smooth
boundary.
IIC e a
100-150 cm (3 9 -5 9 i n ) l i g h t brown ( 7 . 5 YR 6 / 4 ) c la y loam;
p a le brown (10 YR 6 / 3 ) d r y ; weak f i n e a n g u la r bloc ky s t r u c ­
t u r e ; s l i g h t l y h a r d , f r i a b l e , n o n s t i c k y , n o n p l a s t ic ;
prominent calcium carbonate cutans on low er s u rfa c e s o f
fr a g m e n ts , prominent calcium carbonate cutans throughout
th e s o i l .
V e g e ta tio n :
P ico,
.
L o c a tio n :
SW 1 / 4 , SW 1 / 4 , Sec 2 3 , T12N, R8E, Meagher County, Near
j u n c t i o n Deadman and Sheep Creek.
Remarks:
Sample c o l l e c t e d by Herb H o l d o r f .
Table 19. Chemical Properties by Horizon.
Horizon
Depth
(cm)
Fe*
Mn*
Cu*
Zn*
Ca
ppm
Na
K
me/100g
P*
N
ppm
%
pH
CEC
CEC
( pH7) (pH8.2)
me/100g
A ll
A12
A13
A14
B21ir
B22
C
0
10
23
41
58
97
127
10
23
41
58
79
127
182
41
28
28
28
21
19
20
128
90
52
52
34
52
16
6
4
3
3
2
4
9
2.3
1.9
1.3
.7
1.7
4.0
6.2
4.6
2.7
2.6
.9
.6
.5
1.0
.7
.6
.6
.4
.4
.2
tr
tr
tr
tr
tr
tr
tr
1.2
1.2
.8
.7
.5
.4
.5
120
124
156
212
220
46
37
.634
.432
.361
.342
.218
.056
.010
4.8
5.1
5.3
5.3
5.4
5.3
5.3
B21
B22
I IA2
IIAB
I
20
56
74
20
56
74
94
28
31
23
8
6
I
I
I
I
I
.4
.3
.2
-
1.5
.4
.6
.7
.3
.1
.2
.3
.4
.3
.3
.3
.4
.3
.1
.1
96
99
6
4
.050
.020
.020
.010
6.7
6.3
6.1
6.1
B21
B22
0
23
23
56
31
34
5
4
-
.6
1.6
5.4
6.4
.7
.6
.3
.3
.4
.4
430
220
.040
.060
6.4
6.2
Truefissure#
B21i r
B22ir
B23ir
IIB 3 1 ir
IIB 3 2 ir
3
13
25
41
61
13
25
41
61
91
28
15
30
23
22
34
8
17
5
6
2
tr
2
7
5
.8
.2
.6
2.0
1.5
1.5
1.1
2.1
1.4
1.0
.8
.6
.8
.6
.5
.1
.1
tr
tr
tr
.5
.4
.3
.2
.1
107
99
16
19
24
.131
.092
.010
.010
.030
5.8
6.0
5.3
5.3
5.3
14.7
11.5
9.5
8.0
7.3
21.3
19.4
10.5
8.9
4.1
Wishard #
A ll
A12
A13
B21ir
B22ir
0
5
18
30
51
5
18
30
51
79
129
61
24
23
19
128
52
19
6
5
3
3
I
3
. 2
1.2
.6
.8
.7
33.9
20.9
11.3
8.7
9.3
1.9
1.2
.7
.4
.5
tr
tr
tr
tr
tr
.5
.4
.3
.1
tr
78
44
26
10
9
.390*
.240*
.130*
.083
.049
5.4
5.5
5.9
6.0
6.1
41.4
30.2
19.8
13.6
12.2
43.5*
36.7$
24.5$
17 .2**
14 .9**
B2
11A21
IIA22
8
20
38
20
38
58
55
71
-
-
23
12
I
tr
tr
1.1
.4
.2
3.4
4.5
10.8
.6
1.1
1.1
.i
.i
.i
.8
.3
.2
275
21
2
.101*
.087*
.010*
5.3
3.2
6.0
27.7
13.3
14.7
24.7
13.8
13.3
Holloway+
B2
I IA2b
5
25
25
81
68
49
90
5
tr
tr
1.2
.2
3.3
1.7
1.2
.8
.i
.i
.8
.1
201
35
.096
.016
5.5
5.6
18.0
4.4
17.3
4.6
Spring Emery*
B21ir
B22ir
11A2
0
15
33
15
33
58
96
56
25
260
34
9
8
2
2
.4
.3
4.2
3.8
-
.5
.4
1.6
.5
.5
.4
.9
.6
.3
1200
1200
58
.050
.020
.050
5.4
6.2
6.5
Buckhouse#
ID
C
Unnamed 4*
Felan+
I
-
_
23.0
19.9
17.6
15.2
11.7
5.7
5.3
-
31.8
26.8
21.6
19.4
14.6
7.1
6.7
14.2
16.0
3.1
-
-
13.1
12 .6**
34.9
33.5
14.6
L aboratory C h a r a c t e r i z a t i o n
Unnamed 3*
CD
Mg
Table 19 Continued
H o rizon
Depth
(cm
Fe*
Mn*
Cu*
Zn*
Ca
ppm
B2
IIB
0
18
18
38
67
74
12
12
B ir
IIB
10
28
28
53
109
56
71
I
B ir
11A2
IIB 2+
B21
I IA+B
2
28
41
3
25
28
41
79
25
61
85
49
45
112
55
B21
IIB 3
0
18
18
28
Al
B21
B31
B32
0
5
13
23
B2
B3
H ilg a rd *
B2
Holloway V*
Sugarloaf I *
Elkner V2*
I
Cabinet*
C
13
O
Krause*
CVJ
Elkner V I*
§
Unnamed 5
Sugarloaf 2*
%
Elkner*
S
CD
Unnamed 2
Unnamed I *
Mg
Na
K
me/IOOg
P*
N
ppm
%
pH
me/IOOg
.5
.5
3.8
8.1
.5
1.9
.4
.4
.3
.2
536
115
.010
.040
5.8
6.4
.3
.4
.4
.3
3.0
2.3
.4
.4
.6
.4
.2
tr
194
19
.060
.010
5.5
5.6
34
8
8
52
60
.6
1.2
1.5
.8
1.4
.5
.4
.4
1.5
.5
3.8
4.6
7.3
8 .4
4.2
.5
1.5
4.6
1.1
.8
.6
.4
.4
.3
.3
.6
.3
.4
.9
.2
275
11
24
28
2
.090
.020
.020
.082
.040
5.7
5.4
5.2
6.3
6.6
68
20
90
2
.5
0
.6
.3
.7
.7
.1
tr
.5
.5
.19
tr
137
46
.030
.020
5.2
6.1
5
13
23
51
252
93
68
17
165
34
19
4
1.5
.8
1.4
1.2
_
16.7
8.1
6.5
6.5
3.0
1.5
1.3
1.1
.5
.5
.5
.5
.8
.8
.8
.5
78
339
194
35
.140
.7
.4
.2
5.7
6.1
6.0
6.7
0
20
20
45
151
67
90
16
1.3
1.2
.9
.3
7.3
10.0
1.5
2.0
.4
.4
.5
.4
372
124
.080
0
20
63
6
1.2
.4
4 .6
1.3
.4
.2
11
A2
B21ir
I IB31
0
5
13
25
13
61
96
75
26
203
6
I
1.0
.3
.3
2.0
.3
.2
1.9
.7
1.1
.3
.1
.1
.5
.5
.4
.2
.1
tr
Al
B2
B31
0
3
15
3
15
30
14
14
-
203
627
356
.7
.4
.1
.5
.2
11.2
2.7
2.6
1.7
.5
.7
.3
.2
.3
A2
IIC
0
15
15
73
151
34
52
5
1.2
1.6
1.5
.2
9.1
10.2
2.0
2.5
A2
I IB2
0
15
15
100
68
15
5
5
1.2
2.0
.6
.3
15.0
34.0
1.8
1.2
I
I
_
CEC
CEC
( PH7) (pH8.2)
-
*
17.2
16.9
-
41.7
5.7
-
24.7
10.1
16.7$
24.4
8.5
-
13.6
2.3
_
_
-
-
36.6
17.3
16.0
9.2
5.6
6.1
-
20.8
17.0
.050
5.6
-
22.4
88
124
24
.060
.040
.020
4.9
5.1
5.4
-
10.2
9.3
5.2
.8
.7
.2
96
177
43
.120
.110
.060
6.0
5.8
6.0
-
.3
.3
1.2
.5
219
43
.050
.010
.3
.3
.4
.2
32
11
.010
.020
-
.030
.050
-
-
0
-
21.4
10.1
6.1
5.8
6.1
-
15.5
16.7
6.2
7.1
-
14 .5 **
1 3 .1 **
Analysis by +Montana State U n iversity S oil Testing Lab, !A uthor, * +Murray Klage1s Lab, +Soil Conservation ServiceR iversid e, #Soil Conservation S ervice-Lincoln
97
Table 20.
Physical Properties by Horizon.
Horizon
Sand
S ilt
(%)
Clay
Bulk
Density
1/3BW
15BW
PAW
(g /C C )
A ll
A12
A13
A14
B 2 1 ir
B22
C
40
43
40
40
39
46
36
49
48
51
52
54
50
59
11
9
9
8
7
4
5
B21
B22
I IA2
I IA+B
24
21
43
62
75
49
14
4
8
-
-
-
-
-
Unnamed 4 * *
B21
B22
18
17
69
77
13
6
T r u e fis s u r e #
B 2 1 ir
B 2 2 ir
B 2 3 ir
I IB 3 1 ir
I IB 3 2 ir
24
28
36
48
59
70
67
55
47
37
6
5
9
5
4
Wishard+
A ll
A12
A13
B21i r
B22i r
17
20
21
25
37
66
64
67
65
60
Felan+
B2
I IA21
IIA 2 2
33
23
29
Holloway
B2
I IA2b
27
56
Backhouse#
Unnamed 3 *
.7 8
.79
.70
.70
.90
1 .6 0
2 2 .6
2 2 .2
-
-
-
10.9
11.2
10.4
9 .0
6 .5
3 .2
3 .1
1 1 .4
1 1.8
-
4 8 .9 $
6 2 .6 *
1 9 .6 *
2 1 .7 *
1 0.8 $
2 2 .8 $
3 .0 $
5 .2 *
5 5 .7 $
5 3 .4 $
1 0 . 7 * 4 5 .0
1 3 .4 $ 4 0 .0
.68
.75
1.29
1.3 8
1 .4 0
4 7 .2
4 2 .0
2 2 .5
2 0 .1
1 1 .8
1 0 .8
5 .4
3 .6
3 .0
35.4
3 1 .2
17.1
16.5
18
17
12
10
3
.60
.86
.80
1.25
1.3 4
6 4 .3 *
4 9 .7
5 1 .5
2 4 .4
2 0 .4
4 0 .7
1 4.6
9 .9
5 .8
4 .0
2 3 .6
35.1
4 1 .6
18.6
16.4
64
58
60
3
19
11
.71
.88
1.25
3 0 .8
2 9 .9
2 4 .0
12.1
5 .9
6 .8
18.7
2 4 .0
17.2
63
39
10
5
.87
13.1
15.1
9 .5
2 .8
3 .6
12.3
-
-
-
38.1
3 9 .8
16.6
16.5
-
98
Table 20 Continued
Horizon
Sand
S ilt
(%)
Clay
1/3BW
15BW
PAW
5 9 .2
6 2 .0
2 0 .4
2 0 .5
18.5
6 .4
3 8.7
4 3 .5
14.0
-
3 6 .9
2 4 .1
12.2
8 .7
2 4.7
13.4
-
6 5 .9
17.9
2 8.0
2 .0
3 7.9
15.9
-
4 6 .4
2 8 .5
3 5 .6
13.9
7 .5
16.2
3 2 .5
2 1 .0
1 9.4
-
2 6 .2
8 .4
8 .8
4 .1
1 7.4
4 .3
-
2 3 .7
1 0 .8
8 .8
1 .5
14.9
9 .3
6 4 .5
4 3 .6
4 4 .7
3 3 .6
2 3 .9
13.1
12.6
7 .7
4 0 .6
3 0.5
32.1
2 5.9
2 6 .0
1 9.2
10.7
8 .5
15.3
10.7
Bulk
Densi ty
(g /C C )
.90
.90
B 2 1 ir
B22i r
I IA2
34
36
70
55
51
23
11
13
7
B2
IIB
36
67
54
25
10
8
Bi r
IIB
21
57
62
36
17
7
Bi r
IIA 2
IIB 2 +
53
32
7
38
53
43
9
15
50
B21
IIA+B
58
55
29
35
13
10
B21
I IB3
57
84
32
13
11
3
Al
B21
B31
B32
26
24
20
61
65
69
13
11
11
-
-
-
S u g a rlo a f 2 *
B2
B3
58
41
30
44
12
15
H ilg a rd *
B2
17
58
25
-
3 5 .4
13.9
2 1 .5
HollowayJ
A2
B 2 1 ir
IIB 3 1
47
57
71
45
33
23
8
10
6
-
3 0 .2
1 7 .8
9 .0
8 .3
6 .7
2 .5
2 1 .9
11.1
6 .5
Al
B2
B3
65
68
82
27
23
12
8
9
6
S pring Emery*
S u g a r lo a f I *
E lk n e r V2*
C a b in e t*
Krause**
E lk n e r V lJ
Unnamed 5 *
E lk n e rJ
-
.93
-
-
1 .1 4
1.25
-
-
_
-
-
-
-
-
-
-
-
-
99
Table 20 Continued
Horizon
Unnamed 2** *
Unnamed I * *
A na lys is by:
Sand
S ilt
(%)
Clay
A2
IIC
29
31
48
39
24
30
A2
I IB2
13
39
56
39
31
22
Bulk
Density
(g /c c )
-
-
1/3BW
15BW
PAW
33.2$
2 2.0 $
8 .6 $ 2 4 .6
7.7$ 14.3
3 1 .7 $
3 2 .1 $
1 7 . 4 * 14.3
1 2 . 3 * 1 9 .8
*Montana S ta te U n i v e r s i t y S o il T e s tin g Lab, * Author,
**M u rra y K lage's Lab, + S o il Conservation S e r v ic e R i v e r s i d e , # S o iI Conservation S e r v i c e - L i n c o l n .
Figure 9.
X -r a y d i f f r a c t i o n p a t t e r n s , Buckhouse
Mg-saturated
(Angstroms)
K-saturated 350o/500°
ig u r e 10.
I
X -ra y d i f f r a c t i o n p a t t e r n s , T r u e fis s u r e
Mg-saturated
(Angstroms)
K-saturated 350o/500o
ig u r e 11.
X -ra y d i f f r a c t i o n p a t t e r n s , Cabinet
M g-saturated
(Angstroms)
K -s a tu r a te d 350o/ 5 0 0 °
ig u r e 12.
CO
X -ra y d i f f r a c t i o n p a t t e r n s , Krause
O
Mg-saturated
(Angstroms)
K-saturated 350o/5 0 0 °
ig u r e 13.
X -r a y d i f f r a c t i o n p a t t e r n s , S u g a rlo a f I
Mg-saturated
(Angstroms)
K-saturated 350o/5 0 0 °
ig u r e 14.
Mg-saturated
(Angstroms)
X -ra y d i f f r a c t i o n p a t t e r n s . Spring Emery
K-saturated 350o/5 0 0 °
ig u r e 15.
X -ra y d i f f r a c t i o n p a t t e r n s , H ilg a r d
Mg-saturated
(Angstroms)
K-saturated 350o/5 0 0 °
ig u re 16.
X -ra y d i f f r a c t i o n p a t t e r n s , S u g a rlo a f 2
Mg-saturated
(Angstroms)
K-saturated 350o/5 0 0 °
Figure 17.
X -ra y d i f f r a c t i o n
p a t t e r n s , E lkn e r
o
OO
Mg-saturated
(Angstroms)
K-saturated 350o/500°
APPENDIX 4
Unpublished P r e lim in a r y Data from the
S o il Conservation S e rv ic e
Table 21.
V o lca n ic Ash In flu e n c e d S o il
by SCS.
S e rie s in Montana Recognized
Previous
C l a s s i f i c a t i on
P resent
Cl assi f i c a t i on
Buckhouse
Chernozem
Typic Cryandept
T ru e fis s u re
Brown P o d zo lic
E n tic Cryandept
Hebgen
Grey Wooded
E n tic Cryandept
Coerock
L ith o s o ls
L i t h i c Cryandept
Blackburn
Brown P odzolic
Andie Cryochrept
Craddock
Brown P odzolic
Andie Cryochrept
Felan
Brown P o d zo lic i n t e r Gray Wooded
Andie Cryochrept
H o ! I oway
Brown P od zo lic
Andie Cryochrept
Upsata
Brown P o d zo lic
Andie Cryochrept
Wessell
Brown P od zo lic
Andie Cryochrept
E lkn e r
Brown P o d zo lic
Andie Cryochrept
Bata
Brown P o d zo lic i n t e r Gray Wooded
Andeptic C ry o b o ra lf
Savenac
Brown P od zo lic
Andeptic C ry o b o ra lf
Sherlock
Brown P o d zo lic
Andeptic C ry o b o ra lf
At suborder l e v e l :
At subgroup l e v e l :
Andeptic C ry o b o ra lf
Tenibac
Tamely
Brown P odzolic
Andeptic C ry o rth e n t
Waits
Podzols
Andie Xerochrept
Nevine
Brown P od zo lic
Andie Xerochrept
T o te la k e
Brown P o d zo lic
Andie Ustochrept
Krause
Brown P od zo lic
Andie Ustochrept
no
UNITED STATES GOVERNMENT MEMORANDUM
To:
H erschell D. Hurd, S ta te C o n serva tio n is t
SCS, P. 0 . Box 855, Bozeman, Montana
ATTN: Dave R. C a w lfle ld , S ta te S o il S c ie n tis t
Date:
From:
Robert B. Grossman, Head, S o il Survey Lab orato ry, SCS,
4th F lo o r, 1325 "N" S tr e e t, Lincoln 8 , Nebraska
S u bject:
G ran ite and Missoula C ounties, Montana--Sand Mineralogy
March 25, 1963
I have examined the sands from the p a r t ic le - s iz e a n aly sis fo r the s o ils
sampled in G ran ite and Missoula Counties in 1961. Unless in d ic a te d o th e r­
w is e , the observations p e rta in to the very f in e sand f r a c tio n . We hope
to do a l i t t l e c la y m in era lo g ic al work in cooperation w ith John Cady, the
re s u lts o f which w i l l be sent l a t e r .
Quartz commonly runs about 50 percent in most horizons examined. From
10 to 30 percent o f the g rain s are id e n tifie d fe ld s p a r *.
Ferromagnesian
m inerals (am phibole, pyroxene) and the e p id o te -z o is ite group are very scarce.
Mica is ra re except in the lower p a rt o f Loberg 2 0 -4 . Grains o f what w il l
be re fe rre d to as h ig h ly a lte r e d fe ld s p a r are abundant. These g rain s appear
to be composed la rg e ly o f c la y -s iz e m in e ra ls , and in most instances they
cannot be id e n t if ie d as a lte r e d fe ld s p a r except by in fe re n c e .
In many
in s tan ce s, the g rain s co n sist o f an in te rg ro w th o f a lte r e d fe ld s p a r and
q u a rtz.
These grains o f h ig h ly a lte r e d fe ld s p a r (o r grains w ith p arts o f
h ig h ly a lte r e d fe ld s p a r) account fo r from 15 to over 50 percent o f the
very f in e sand.
F a ir ly fre s h fe ld s p a r occurs in asso ciatio n w ith a l l grada­
tio n s to the h ig h ly a lte r e d fe ld s p a r.
The a lt e r a t io n o f the fe ld s p a r shows l i t t l e change w ith depth. Apparently
the a lt e r a t io n p a tte rn as observed today is la r g e ly in h e rite d from the
parent m a te r ia l, and pedogenic w eathering may a c tu a lly be s lig h t even
though the sola show evidence o f strong m ineral a lt e r a t io n .
I suspect
th a t the a lt e r a t io n o f the fe ld s p a r is due in p a rt to very low-grade metamorphism o f the sedimentary rock.
Probably the e x te n t o f fe ld s p a r a l t e r a ­
tio n fo r a p a r tic u la r p r o f il e depends on the e x te n t to which low-grade
metamorphism has a ffe c te d the parent m a te r ia l.
In general the s o ils th a t
contain fragments o f reddish sandstone, as opposed to gray s l l ts to n e (? ),
have more q uartz and a lower pro po rtio n o f h ig h ly a lte re d fe ld s p a r.
In
passing, i t should be noted th a t these h ig h ly a lte r e d grains may have
some c a tio n exchange c a p a c ity .
This could lead to higher apparent cla y
exchange ca p a city (c a lc u la te d by d iv id in g the measured ca tio n exchange
ca p a city by the cla y percentage) than the tru e valu e.
The d iffe re n c e
between the apparent and tru e values would be la rg e r fo r horizons low in
c la y .
By id e n t if ie d fe ld s p a r I mean grains th a t are fresh enough to be
id e n tifie d as fe ld s p a r from c ry s ta l form , index o f r e fr a c tio n , tw in ­
n in g , o r a combination.
Ill
2 - H erschell D. Hurd, March 25, 1963
Of p a r tic u la r in te r e s t is the abundance o f glass shards in the upper two
m ineral horizons ( B ir ) o f Holloway and the e s s e n tia l absence below.
(The
o th e r s o ils a l l co n tain some glass shards in the upper surface and second
horizons but not in excess o f 10 p e rc e n t.) As seen under the stereoscopic
microscope, the sands o f the B ir contain an abundance o f brownish porous
aggregates. These aggregates may have considerable exchange ca p a city and
c o n trib u te s u b s ta n tia lly to the high apparent exchange cap a city o f the
c la y o f these horizons.
The fo llo w in g are observations on the In d iv id u a l s o ils :
Greenough - Quartz subordinate to h ig h ly a lte r e d fe ld s p a r.
Several percent
glass shards in surface h orizo n .
Ferromagnesian m inerals and e p id o te z o is it e are very scarce. A few g rain s o f to urm aline occur.
Some o f the
id e n t if ie d fe ld s p a r is probably a l b it e .
As seen under the stereoscopic
microscope, 15345 and 15348 o f 32-1 co n tain numerous brownish, porous
aggregates.
HolI oway - Estimate 60 percent glass shards in su rface and 50 percent in
subsurface mineral horizons o f 3 2 -5 , and 80 and 60 percent in comparable
horizons o f 3 2 -6 .
Only an occasional shard in the th ir d horizon and
e s s e n tia lly none below th a t. Many o f the shards are cracked and furrowed
(lo o k l ik e tre e b a rk ), and most have s o lu tio n embayments. Q uartz, h ig h ly
a lte r e d fe ld s p a r and Id e n t if ie d fe ld s p a r are the th re e major co n stitu e n ts
below the second horizo n .
Many grains appear to co n sist o f an interg ro w th
o f q u a rtz and h ig h ly a lte r e d fe ld s p a r.
Very few ferromagnesian m in era ls.
A few m u scovite(?) g rain s in 32-6.
Loberg - Several observations made w ith the stereoscopic microscope may
be p e rtin e n t.
The coarser sand fra c tio n s are la rg e ly reddish brown sand­
stone instead o f grayish s ilts to n e as in Greenough and Holloway. A higher
p roportion o f w ell rounded grains occur than in Greenough and Holloway.
A golden-colored micaceous m ineral occurs in the lower p a rt o f 2 0 -4 .
Estim ate about 50 percent q u a rtz , 20 percent h ig h ly a lte r e d fe ld s p a r and
20 percent id e n t if ie d fe ld s p a r. Quartz occurs more commonly as d is c re te
grains ra th e r than as an in te rg ro w th w ith h ig h ly a lte re d fe ld s p a r.
Prob­
ably a sm aller percentage o f h ig h ly a lte r e d fe ld s p a r than in Greenough and
Holloway.
A few amphibole in upper two h o rizo n s ; very scarce below. Sur­
face horizon contains 5 to 10 percent glass shards and the subsurface 2 to
5 percent in 2 0 -3 ; comparable horizons o f 2 0 -4 contain somewhat le s s .
Very
l i t t l e glass occurs below the second horizo n .
In p r o f ile 2 0 -4 , micaceous
grains appear in 15423, reach 20 to 30 percent by 15426, and then drop
sharply back in 15427.
15427 is high in grains o f h ig h ly a lte re d fe ld s p a r.
The mineralogy suggests two lith o lo g ic a l d is c o n tin u itie s ; across 15423,
and between 15426 and 15427. An increase in the apparent exchange ca p a city
o f the c la y in the lower p a rt o f 20-4 coincides w ith the increase in micace­
ous g ra in s .
112
3 - H erschell D. Hurd, March 25, 1963
P h llip s b u rg - Stereoscopic microscope: The coarser sand is dominated by
fragments o f reddish sandstone. Many o f the coarser grains are q u ite w ell
rounded.
Q uartz, id e n t if ie d fe ld s p a r , and h ig h ly a lte r e d fe ld s p a r in th a t order
predominate.
Perhaps a somewhat lower p ro po rtio n o f h ig h ly a lte r e d f e l d ­
spar than in Greenough, Hollow ay, o r Loberg. A ll accessory m inerals very
minor.
About 5 percent glass shards in surface horizon o f 20-5 and some­
what less in 2 0 -6 ; very l i t t l e below the surface h orizo n . A few grains
o f prim ary carbonate occur in the lower horizons.
P in t la r - Stereoscopic microscope:
brown sandstone than does 20 -2.
P r o f ile 20-1 contains more reddish
About 40 to 50 percent q u a rtz , 30 to 40 percent h ig h ly a lte re d fe ld s p a r
and 20 percent id e n t if ie d fe ld s p a r.
5 percent glass shards in su rface o f
20-1 and 5 to 10 percent in 2 0 -2 ; the re s p e c tiv e subsurface horizons con­
ta in less than h a lf th a t in the su rfa ce .
Accessory m inerals are very scarce.
A s u b s ta n tia l p a rt o f the id e n t if ie d feld sp ars are probably a l b it e .
The
surface horizon o f 20-2 contains more ep id o te than horizons below. Both
p r o file s co n tain a tra c e o f mica.
T ark io - There is so l i t t l e sand and coarse s i l t th a t microscopic observation s are o f doubtful valu e.
The very fin e sand has a mineralogy essen­
t i a l l y s im ila r to the o th e r s o ils .
One d iffe re n c e is somewhat more glass
shards in the su rface horizon than fo r the o th e r p r o file s w ith the excep­
tio n o f Holloway. The su rface horizons are r e la t i v e l y ric h in p la n t o p a l,
p a r t ic u la r ly in the coarse s i l t f r a c tio n .
Elongate grains predominate in
the f in e s i l t .
Yourame - Stereoscopic microscope: The co arser sand dominantly gray s i l t stone or sandstone th a t shows s c h is to s ity .
About 50 percent q u a rtz , decreasing below 15394 and reaching a low o f 20 per­
cent in the bottom h orizo n . Most o f the non-quartz grains are h ig h ly
a lte r e d fe ld s p a r interg ro w th s w ith q u a rtz o r d is c re te grains o f h ig h ly
a lte r e d fe ld s p a r. The su rface horizon contains 10 percent glass shards
and the subsurface 5 p e rc e n t, w ith l i t t l e glass below. E s s e n tia lly no
ferromagnesian m inerals are p resent.
Some o f the id e n tifie d fe ld s p a r is
r e la t i v e l y fre s h .
The bottom horizon contains m ainly h ig h ly a lte re d
fe ld s p a r.
The high p ro po rtio n o f h ig h ly a lte r e d fe ld s p a r and the apparent
s c h is ta s ity o f the coarser sands may be r e la te d .
The high apparent exchange
c a p a c ity , p a r t ic u la r ly fo r the bottom h o rizo n , may be the r e s u lt o f an
exchange cap a city c o n trib u tio n from grains o f h ig h ly a lte re d fe ld s p a r in
the non-clay fr a c tio n .
c.
F.
A.
J.
L.
G.
R.
W.
A.
A.
J.
R.
G.
T.
D.
W.
M.
H.
Mogen
C a r lis le
Aandahl
Cady
Alexander
Smi th
Simonson
Johnson
Post
113
UMTKD JT-ViUJi OOVBron-IQiT MMOCAiaiU-!
To:
Hcrcchel )j. Hurd, Htatc Conservationist,
Dite:
DCS> F. 0. Box -'155; Bozeman, Montana ' / ' ’7 1 5
ATf?!: Hive R. Caulfield, State Soil Scientist
From:
Robert B. Grossman, Head, Soil Survey laboratory, SCS,
Uth Floor, 1325 "N" Street, Lincoln, Nebraslia 68508
Subject:
SOILS - Mineral and Missoula Counties, I 96 U - Occurrence of Glass
July 7, 1965
I
A"
Ve have made a cursory examination of the sands from selected horizons of
Craddock, Drexel, and Horsciiead to determine the abundance of volcanic
Class. The observations are given below. Earlier, preliminary observations
•.-ere distributed on the glass content of Truefissure and Wichard.
With the
exception o f W
Lshard, a l l the soils examined contain appreciable volcanic
glass.
Hcman numeral horizon notation would seem necessary.
I suggest
that another p ro file of Wishard should be grab sampled to examine fo r glass.
I f i t turns out that glass is absent in Wlshard, i t would suggest the parent
material was emplaced a fte r the ash f a l l .
A ll the samples contain a high proportion of altered feldspar aggregates
that presumedly are the result of Itiv-grade metamorphicm, not s o il weathering.
They arc sim ilar in th is respect to the 1961 samples from Granite and Missoula
Counties.
These sand- and s ilt- s iz e aggregates should have some cation
exchange capacity.
Cnc would expect that such grains would be more easily
broken down than an assemblage of discrete quartz and feldspar, where the
feldspar is re la tiv e ly fresh.
Cur concern with glass may lead us to
overlook th is characteristic of the mineralogy of these soils developed on
vc -.lily metamorphosed sedimentary rocks.
Craddock s6 hMont-31--5
No. 19667
Appreciable volcanic glass in the very fin e sand with perhaps
more in the coarse s i l t .
LGL No. 19691
No glass in the very fine sand; largely aggregates of altered
feldspar or mosaics of quartz and altered feldspar, with some
discrete quartz; a few pyroxene.
LGL
Drexel E6lK-or*t-31-^
LSL Ho. 19665
Significant volcanic glass in very fine sand, perhaps less
than in 19687 ; grains consisting o f mosaics of altered
feldspar and quartz are very common; some pyroxene, a
portion glass-enclosed.
LGL No. 19700
No glass in very fine sand,
tost o f the very fine sand con­
sists of abundant s ilt- s iz e and coarse clay-size crystals of
mica or mica-like minerals arranged in sub-parallel orienta­
tio n and held in an extremely fine grain matrix having grayish
interference color; grains have ragged edges and are
somewhat elongate.
• ilerechell T. Hurd, July f, 1^65
114
Hersehead S64M3nt-32-l
ISL No. 19729
ISL No. 19732
Appreciable glass In the very fin e sand—more than In
Craddock 19687 or Erexel 19665 .
Aggregates of altered fe ld ­
spar are common; more lik e those in Craddock than those in
Drexel.
A few fcrrcmagnesian minerals present.
Some glass (10-15 percent) in the very fin e sand; less than
in 19729.
Truefissure S64-Mbnt-31-1
LSL No. 19710
cc:
No glass; largely altered feldspar aggregates and mosaics of
altered feldspar and quartz.
C. A. Mbgen
E. M. Richland
A. R. Southard
L. T. Alexander
G. D. Ehith
J. L. Hctzcr
115
UKITRO STATRa GOX'RRi’tiRMT HEt’I01uv?;Ri:!
To:
Hci^uhell I). Hurd, State Cozitiervatior.is t,
Tbtc:
SCS, P. 0. Box 855) Bozeiran, Montana 59715
ATT'N: Dave R. Caulfield, State Soil Scientist
August 13, 1965
From:
Robert B. Grossman, Head, Soil Survey Laboratory, SCS,
Uth Floor, 1325 "N” Street, Lincoln, Nebraska 68508
Subject:
SOILS
- Cascade, Mineral, and Missoula Counties - Clay Mineralogy
Vbrren Iynn has determined the clay mineralogy on selected so ils of Craddock,
Drexel, Horseheod, Truefissure, and Tarkio.
With the exception o f the la st
named, the determination6 were made on the same samples fo r which the s o il
mincralogical observations were distributed July 7, 1965Warren's comments
fo llo w :
Horsehcad, Craddock, and Truefissure are andic in th e ir upper pa rts,
Drexel
and Visbcird lik e ly contain c ry s ta llin e clays throughout.
Upper horizons of
Drcxcl ray contain s u ffic ie n t glass fo r andic, but probably would not cnalify
on the basis of clay mineralogy.
Wishard apparently would not q u a lify fo r
andic either on clay mineralogy or abundance o f glass in the s i l t and sand.
Ihe exchange capacity fo r clay ratios may suggest a more extensive influence
o f amorphous material than the mlneralogical observations to date indicate.
For example, t i e 7 to 12 inch horizon of '.Jishard has wide ra tio s of each -..-.go
capacity and of 15 -bar water retention to clay, but yet has l i t t l e glass in
the sand. This may be a re fle c tio n o f organic matter or i t may not.
Ihc
story is not a l l in yet.
Two of the samples, 19687 and 19732, dispersed in a mild acid, but would not
disperse in water or a mild base.
Craddock S6 UtIont-31-3
TSL No. 19687
Dominated by amorphous material.
Crystalline clays barely
detectable.
Acid dispersed sample yielded small lUA peak,
probably verr.iculite.
ISL Ho. 19691
Contains w e ll-cry sta llize d montmorillonite and mica, probably
also some halloysite and venniculite.
Interlayer c h lo rite montmorillonite (or possibly venniculite) is present.
Itefcm o rillo n ite remains at lUit a fte r sodium dispersion which
indicates a high-charge montmorillonite or an influence of the
c h lo rite interlayers.
Drexel SbkMont-31-^
LSL Mo. 19695
V e il-crysta llize d k a o lin ite , mica, end venniculite present
along with trace amounts o f c lilo rite and montmorillonite.
ISL No. 19700
W ell-crystallized mica, k a o l'n ite , and verniculltv. ..re
abundant.
Ehaller amounts of montmorillonite nod z'h-t a p p ea rs
to be gibbsitc r'.e a1: 0 presai t .
2 - nei-schell D. Hard, Augast 13, 1965
Ilfi
Horsehead S6 -IMnnt-32-1
ISL No. 19729
Anoi-rhous materials dominate.
Trace amounts o f k a o lin ite ,
mica, and montmorillonlte are detectable.
ISL Ho. 19732
Amorphous materials dominate.
No crysta llin e clays detected.
The sample dispersed in a mild acid but not in water or a mild
base.
Truefissure SS1IKont-31-2
ISL Ho. 19710
Moderate amounts o f w e ll-crysta llize d mica and vermiculite,
with less ka o lin ite and a small amount of montmorillonlte are
present.
Monad SuUKont-7-2
ISL No. 19632
JIB23t
40-49 inches
Tlie c la y is high in montmorillonlte with a moderate amount o f ka o lin ite and
a l i t t l e mica also present.
Hie montmorillonlte retains a 14-A spacing a fte r
sodium dispersion.
This indicates that divalent cations remain on the
exchange and suggests a high-charge montmorillonlte.
The mineralogy is mixed.
Tiger and Highwood may liave sim ilar clay mineralogies.
Tarklo 96] Mant-32-3
ISL No. 15356
Ag
0-5 inches
ISL No. 15359
B22
12-20 inches
Both horizons contain abundant mica, moderate k aolinite and a trace of chlo rite .
The Ag contains a moderate amount o f montmorillonlte which increases consider­
ably in the Bgg.
cci
C.
E.
A.
L.
G.
J.
J.
The mineralogy is mixed.
A Mogen
M. Richland
R. Southard
T. Alexander
D. Snith
L. Retzer
0. Cady
117
L. T . A Icxnnder, C h ie f , Sol I Survey L a b o ra to rie s ,
SCS, Plant Industry S t a t i o n , B e lts v l I l a , Maryland
h '" "
20/0S
”
I0 S
June G. Ho I gh, Soil S c i e n t i s t , SCS, Cut Bank,
Montana
59427
SOILS - Volcanb Glass - F ie ld and Laboratory Study In G la c ie r County,
Montana, Soils
Thanks to you and Dr. TeSe fo r the report o f July 15. 1966, o f the above
study. Since the snow and cold came to my area I have taken the time to
consider the report thoroughly.
I b e lie v e we have answered the primary study question: What Is the d i s t r i b u ­
t io n and influence o f volcanic ash In the s o i ls o f G la c ie r County? The
samples were token In div erse areas o f the county from s o i l s on varying
kinds o f transported parent m ateria l and from co n tras tin g kinds o f s o i l s .
Considering the sampling and the d a ta , we can say:
1.
2.
3.
Vo lcanic glass occurs In a t lea st very small amounts In a l l so ils
o f the area.
There Is a g rea ter amount of glass In the surface horizons of
most s o i l s .
The amount o f glass even In the surface, horizons ( I to 3V. of the
coarse s i l t 20-50 microns) is probably not s i g n i f i c a n t In the
genesis, morphology, o r c l a s s i f i c a t i o n o f these s o i l s .
I note th at the s o i ls w ith the higher glass content In the surface occur In
the higher p r e c i p i t a t i o n portio n o f the County. This might be expected from
e i t h e r ra in ca rryin g the ash or more abundant vegetation preserving the ash
where i t f e l l .
I also note th a t 4 o f the 5 s o i l s , w ith only a tra ce o f ash
in the surface h oriz o n , could have developed In Iac u s trlan or a l l u v i a l
deposits deposited a f t e r the ash f a l l .
In the f i f t h ( A - 6 4 - H o n t - l8 - l2 ) the
s i t e Is p res en tly exposed to the p r e v a i l in g wind and ash may never have
accumulated.
As there has been no study o f clay In t h is area I t was in t e r e s t i n g to confirm
the dominance of montmorlI l o n l t c In nearly a l l s o i l s . Do you atta ch any
s i g n if ic a n c e to the dominance o f v e rm lc u llt e In the one Sherburne p r o f i l e
(A-64 Mont-IS-Q)? The landscape here was considered by V. C. Alden ns prcWlsconsln and t h is p r o f i l e was sampled w it h i n one h a l f mile of p r o f i l e Ho. 16
as reported In Soil Survey Laboratory Memo No. I , 1952.
L . T . Alexander
- 2Dccembcr 8 , 19 6 6
118
In the Inst paragraph o f your report you point out th at the gloss In the
samples of ash layers was dominantly f ib e rs c r t h in rods.
Is t h is also
tru e o f the glass In the surface horizons o f the s o i ls sampled? I cm
wondering: Does the glass In the surface s o i ls represent the same ash
f a l l as the glass In the e a s i l y recognized layers In wet areas? By now I
have found ash layers In sub-horizons In many places; not only In wet
a r e a s , but In w ell drained uplands.
I b e lie v e now th at ay a t t e n t i o n should be focused on the second p art o f i.iy
o r i g i n a l study p la n; that Is an attempt to use these ash la y e rs , physio­
graphic fe a tu r e s , and s o i l development to e s t a b l is h some age re la tio n s h ip s
(pre-Wisconsin to recent) fo r b e t t e r p r e d ic t io n and c o r r e l a t i o n o f r o i l s .
You a r c , no doubt, f a m i l i a r w ith the work o f Roy E. Wilcox and Howard A.
Powers o f the Geologic Survey and Roald F r y x c l l o f Washington State
U n iv e r s it y In c o r r e l a t i o n and dating o f ash deposits.
In correspondence
w ith Wilcox la s t year he Indicated hopes o f doing some a d d it io n a l work with
ash In Western Montana.
I t Is possible t h a t he would t r y to c o r r e l a t e some
o f my ash finds w ith the Hazama and G la c ie r Peak Ash.
Is there any p o s s i b i l ­
i t y of new SoIl-GcomorphIc study areas f o r our o'm f i e l d In v e s tig a tio n sta ff?
Once again then!: you fo r your p art In th is study.
I t has hccn s tim u la tin g
for me in the sometimes ro u tin e o peration o f f i e l d mapping.
cc :
C. A. Hogen ^
A. R. Southard
APPENDIX 5
P la n t A b b r e v ia tio n Code
A b b r e v ia tio n
Name
O verstory
Abla
Abgr
Laoc
Juoc
P ia l
Pico
Pien
Pimo
Pipo
P o tr
Psme
Thoc
Abies la s io c a r p a
Abies grandis
L a r ix o c c id e n ta l is
Juniperus o c c id e n ta l is
Pinus a l b i c a u l i s
Pinus c o n to r ta
Picca englem anii
Pinus m o n tic o la
Pinus ponderosa
Populus tre m u lo id es
Pseudotsuga menusii
Thuja o c c id e n ta l is
Underst o ry
Acar
Acgl
Acmi
Agsu
A ls i
Aruv
Caca
Cage
Caro
Cara
Chum
Clun
Libo
Mare
Mefe
Pamy
Powh
Rupa
Syal
Vagi
Vase
Veca
Xete
Actea a rg u ta
Acer glabrum
A rc h ille a m ille fo liu m
Agropyron subsecundum
Alnus s in u a ta
A rc to s ta p h y lo s u v a -u rs i
Calam agrostis canadensis
Carex g e r i i
Calam agrostis robusta
Calam agrostis rubescens
Chimaphila umbel l a t a
C l i n t o n i a uni f l o r a
Linnea b o r e a l i s
Mahonia ( B e r b e r i s ) repens
Menzesi a fe r r u g in e a
Pachistim a m y r s in ite s
Poa w heele r i
Rubus p a r r i f l o r a
Symphoracarpus albus
Vaccinium g lo b u la r e
Vaccinium scoparium
Veratrum cal i form'cum
Xerophyllum texax
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