HYDROGEOLOGY OF THE NORTHERN TAOS PLATEAU, TAOS COUNTY, NORTHERN NEW MEXICO
June 2011
AU THO RS: P e g g y S . J o h n so n an d P au l W. B au er
New M e x i c o B u r eau of Geol ogy and M ine r a l Re s our c e s (NMBGMR), a Div is ion of N e w Me x i c o I n s t i t u t e o f Mi n i n g & Te c h n o l o g y
8 01 L e r o y P la c e , S ocorro, N M 87801
CO-31
8500
TC-212
Middlemist
Q
8000
TC-205
Ruil Bros.
Tx
Tb
Tsf
Tb
7500
Tb
Tsf
Tsf
Tsf
Th
7000
Th
Th
Th
Tb
Tao
Tao
Tao
Th
Th
Q
Tvr
Tg
9000
Well Key
8500
RG-63022
Chiflo
Tb
Tvr
Qf
OSE well file number
Well name
Streamflow from the Tusas Mountains is diverted around the Taos
Plateau volcanic field and San
Antonio Mountain via the Rio San
Antonio and the ephemeral Arroyo
Aguaje de la Petaca. Indicators of
infiltration and recharge through
the Taos Plateau volcanic field to
local and regional aquifers include:
Water table surface
in regional aquifer
(Table 1)
(actual elevation, if projected)
Volcanic intervals, Tv
7500
(from well record)
Tvr
Measured water-level
Recorded water-level
Screened interval
7000
Tb
Aquifer Symbols
Well head
8000
Tb
Th
Th
TC-249
BLM Visitors
Center
Tag
Tg
Tsf
X
6500
Cerro de la Olla
east flank
(5.0 Ma)
TC-204
Ezequiel
RG-51763
TC-207
Chiflo
dam site 9a
G EO MO RPHO LO G Y
SE
Elevation feet
above sea level
Red River Gorge
The Taos Plateau is capped by the largest and compositionally most diverse volcanic field of the Rio Grande rift and
contains seven major rift-related fault zones. Pliocene
Servilleta flood basalts form the major aquifer. Other aquifer units include volcanic domes and buried vents, Santa Fe
Group alluvial deposits, lower Tertiary volcaniclastic units,
and Proterozoic granite. A water-table surface defines:
1) Regional west-to-east groundwater flow from the Tusas
Mountains; 2) A groundwater divide aligned with the Rio
San Antonio in southern Colorado; 3) A remarkably flat
hydraulic gradient in the eastern half of the plateau; and
4) Recharge mounds beneath the Rio San Antonio, the Rio
Grande in the Ute Mountain reach, and volcanic domes.
TC-227
Perlite mill
Rio Grande Gorge
9000
TC-223
Stateline
Cerro de la Olla fault
Elevation feet
above sea level
A’
Taos Basin
Brushy-Timber
Mountain Horst
Taos Plateau
Rio San Antonio
G E O LOGY
Groundwater Divide
AB STRA CT
A
NW
Tsf
6500
Vertical Exaggeration = 8x
CO-32
8500
TC-237
Saritas
CO-33
TC-231
Twin Lakes
TC-239
San Luis
Hills
285
Q
8000
Tb
Tsf
Th
X
6500
Tb
Th
Th
Th
285
TC-214
Bagwell
Q
Tb
No data
Th
Th
X
X
No
data
?
Tsf
Q
Q
Ta
7500
Ta
7000
Tsf
Tsf
Tsf
Tsf
6500
10.500
San
Antonio
Mountain
(3 Ma)
Taos Plateau
Tds
Taos Plateau
Horst
TC-217
Alire/Duran/Mueller (aban.)
285
TC-212
Middlemist
Q
8500
Ta
Tx
Ta
8000
Q
Ta
Q
Tb
Tsf
7500
Th
Th
Th
6500
X
G
Elevation feet
above sea level
9000
Tx
Tsf
Th
8000
7500
7500
7000
Th
Tres Piedras Platform
X
X
X
X
Tx
Tsf
Brushy-Timber
Mountain Horst
Cerro del Aire
north flank
(3.6 Ma)
Q
Tr
Tb
Th
Th
X
X
Cerro de la Olla
south flank
(5.0 Ma)
Q
Tb
Tb
Tsf
Th
Th
X
TC-204
Ezequiel
TC-245
Kessler
Brushy
Mountain Tb
Tao
Tsf
6500
Taos
Graben
TC-225
Chiflo dam site 7a
TC-201
Cerrito Negro
Taa
Tb
Tsf
Th
Tr
7000
8000
Q
6500
No
Agua Peaks
(4.1 Ma)
Q
285
8500
8500
Sunshine Valley
X
TC-221
No Agua
TC-234 Perlite Mine
Schofield
WEST
TC-113
Lava Tube
Spring
Tb
Th
X
Elevation feet
above sea level
Tsf
Th
X
EAST
9000
Q Playa
Tb
Th
7000
Playa
Playa
E’
Costilla-Questa
Basin
Tat
Rio Grande Gorge
9000
TC-233
Rio Grande Gorge
10,000
Tb
Tg
Q
G’
EAST
Elevation feet
above sea level
9000
Guadalupe
Mountain
(5.3 Ma)
8500
8000
Q
Tb
7500
Tb
Th
Tdg
Tg
Tag
7000
Tsf
X
Brushy
Mountain
Several faults and associated
horst structures exert some
control over regional groundwater flow:
8000
Tdu
Tsf
Tsf
6500
• Two-thirds of the study area
(453 mi2) consists of closed or
poorly developed drainage
basins, many of which contain
active playas.
San Luis Hills are mainly composed of pre-rift volcanic units.
8500
Ta
Tsf
Th
Th
X
Ute
Mountain
(2.7-2.1 Ma)
Ta
Tb
No data
Tsf
Th
7000
9000
Tb
Tb
9500
Vertical Exaggeration = 8x
TC-211
Chiflo dam
site R-11
Tb
Elevation feet
above sea level
Vertical Exaggeration = 8x
TC-229
Crow
Tx
E
The Taos Plateau regional aquifer is unconfined within Servilleta Basalt
and the upper Santa Fe Group. Most Taos Plateau wells in New Mexico
draw groundwater from the Servilleta Basalt. In Colorado, wells tap
Santa Fe Group alluvium. West of the inferred Western Plateau fault, the
Hinsdale Formation and older volcanic units form the regional aquifer.
TC-226
Shawcroft E
Faults and
Structures
D’
EAST
Elevation feet
above sea level
Red River fault
zone
Vertical Exaggeration = 8x
8500
WEST
H YDR OLO GY
7000
Costilla-Questa Basin
Taos Plateau
Horst
TC-222
Bagwell N
6500
Taos Plateau water well and tank, with Ute Mountain in the distance.
7500
6500
Taos Plateau
9000
• Basalt-capped plateau and
volcanic domes lack
well-integrated surface drainage.
8000
Tsf
Elevation feet
above sea level
The Taos Plateau regional aquifer first discharges to the Rio Grande 33 miles downstream from the CO border in a 1.5-mile reach at the Red River fault zone. Spring
discharge to the Rio Grande is strongly controlled by faults, with most inflow occurring
along two short
river segments
coincident with
the Olla/Ute
Mountain and
Red River fault
zones.
8500
X
D
7500
9000
No
data
Tsf
WEST
8000
Elevation feet
above sea level
Qf
Tb
Tsf
Th
7000
Tb
B’
EAST
Qa
Tb
Tsf
7500
TC-232
Lobatos
Rio Grande Gorge
Vertical Exaggeration = 8x
9000
TC-238
Alta Lake
Costilla-Questa
Basin
San Luis Hills
Horst
Rio Grande Gorge
Elevation feet
above sea level
Chemical, thermal and isotopic data from wells and springs were applied to evaluate
groundwater sources, flow patterns, recharge and discharge zones, and residence times.
Three groundwater sources are identified: 1) Deep inflow from the Tusas Mountains with
depleted deuterium, a positive 18O thermal shift, high silica, warm temperatures, and a
14
C residence time of 5500 to 8000 years; 2) Cool (<16 ºC), low TDS, Ca-Na-Mg-HCO3
water representative of central Taos Plateau recharge, with a mixed residence time of
3500 to 5000 (RCYBP) years, measureable 3H, and 3045 year-old CFC-12 ages; and
3) High TDS, Na-HCO3-Cl water upwelling from a deep saline source near the Red River
and Ute Mountain fault zones.
Taos Plateau
Rio San Antonio
B
WEST
• Red River fault zone
• Gorge fault zone
• San Luis Hills,
Brushy/Timber
Mountain, and inferred
Taos Plateau horsts
• Inferred Western
Plateau fault
• Cerro de la Olla-Ute
Mountain fault zone
• Precipitation increases with
elevation on volcanic domes.
Tertiary volcanic rocks of the Brushy-Timber Mountain horst.
Cerro Chiflo
Cerro de la Olla
Tb
Tb
Tb
Tb
Tg
Tag
Tag
Tg
Data suggest that heat flow
and upwelling thermal water
along rift-margin structures
influence both the flow and
chemical characteristics
of groundwater in the Taos
Plateau regional aquifer.
Q
Start of
Bear Crossing
spring zone
The Red River fault zone cuts across the Rio Grande Gorge.
Small playa lake in a large closed basin north of Cerro de la Olla.
Groundwater Conditions
7600
• Apparent C ages decrease (young) from west to
east (down-gradient) in the aquifer
Rio Grande
5
• Oldest groundwater is underflow from Tusas
Mountains (5500 to 8000 rcybp, < 0.1 TU,
CFC-12 recharge age >55)
State Line gage
State Line
10
Upper
gorge
-2 cfs
Elevation
(feet)
Lobatos gage
14
• Youngest water is mixed with recent recharge in
the central plateau closed basins
(3500 to 4000 rcybp, 0.2–50.8 TU,
CFC-12 recharge age 30-40 yrs)
Costilla Creek
West Rim
15
• Discharge in the Ute Mountain spring zone
(2910 to 3840 rcybp, 0.1 TU) is younger than any
sampled in the Taos Plateau regional aquifer,
suggesting a source from Ute Mountain
• Discharge in the Bear Crossing-Felsenmeere
spring zone (4400 rcybp, 0.1 TU) is consistent
with the Taos Plateau regional aquifer
TS-14
TS-71
TS-113
Chloride
Ute Mtn.
spring zone
+37 cfs
Sunshine
springs
Winograd (1959)
accretion zone
Gorge fault
Cow Patty trail
20
Sulfate
7400
Groundwater age-dating indicates mixing of “old”
and “young” waters:
0
Temperature
Upflow Along Red River and Ute Mtn Faults
characterized by:
• Warm discharge temperature (16.5–18.1 ºC)
• High TDS (>200 mg/L), Na-HCO3-Cl water elevated in
SO4, Br, F, B, Li, As
• 2H and 18O composition similar to Taos Plateau
• Simple mixing in down-gradient well (TC-204) and spring
(TS-8) – 60% Taos Plateau / 40% deep saline
• Saline end member projected to be Na-Cl-SO4 water
7200
Underflow from the Tusas Mountains characterized by:
• Warm discharge temperature (>19 ºC)
• High TDS (>200 mg/L), elevated Ca, Mg, F, Li
• Elevated dissolved SiO2 (>60 mg/L)
• Depleted 2H (<-105 ‰)—high altitude source
• Positive 18O shift of 0.5-1.0 ‰—thermal exchange
G RO UNDWATER DISCHARG E,
STREAM FLO W AND SPRING S O F
THE RIO G RANDE G O RG E
7000
• Gradient change across Western Plateau fault reflects a permeability contrast
between Hinsdale Formation and Servilleta Basalt
• Flat gradient in eastern half of plateau with south and southeasterly flow
• Recharge mounds beneath Rio San Antonio and Rio Grande
• Groundwater divide at Rio San Antonio
• Perched aquifers and recharge mounds associated with volcanic domes
G RO UNDWATER
RESIDENCE TIME
6800
G R O U N DWATER SOU R C ES A N D R EC H A R GE
6600
Groundwater flows west to east from the Tusas Mountains towards the Rio
Grande gorge.
and Ute Mtn. fault
TS-72
100
10,500
(ft asl)
TC-233
9500
4
ica
rbo
nat
e
TC
-20
TC 9
-20
8
80
ate
+B
60
8500
TC-212
(Middlemist)
3580 rcybp
1.25 TU
40 yrs (CFC-12)
TC-209
projected (Rael)
5230 rcybp
0.02 TU
47 yrs (CFC-12)
Playa
8000
Playa
3
1
4
0
100
80
40
60
Calcium
20
100
0
0
2
20
20
4
3
40
60
80
100
0
WEST
Elevation feet
above sea level
Silica
9000
(ft asl)
Deuterium
Vertical Exaggeration = 8x
Recharge from Precipitation on the Plateau characterized by:
• Cool discharge temperature (<16 ºC)
• Low TDS (<200 mg/L), Ca-HCO3 water, variable Mg, Na
• Enriched 2H (≥-100 ‰)
• 2H and 18O composition trends on a MWL from San Antonio Mtn
perched aquifer (TC-233)
-80
8500
No
Agua Peaks
(4.1 Ma)
Tres Piedras Platform
Cerro del Aire
north flank
(3.6 Ma)
TC-201
Cerrito Negro
6070 rcybp
0.04 TU
8000
Cerro de la Olla
south flank
(5.0 Ma)
Brushy
Mountain
7500
δ2H (‰, VSMOW)
6500
Red River
fault zone
-100
-110
Tusas
Mountain
recharge
PROJECT FUNDING
Taos Plateau MWL
δD = 7.2 δ18O + 7.7
Thermal 18O shift
New Mexico Interstate Stream Commission
The Healy Foundation, with Taos County as the fiscal agent
The New Mexico Bureau of Geology & Mineral Resources,
Aquifer Mapping Program
-120
-16
-15
-14
18
δ O (‰, VSMOW)
Bear CrossingFelsenmeere
spring zone
Red River
fault zone
G’
Taos
Graben
EAST
Guadalupe
Mountain
(5.3 Ma)
Ute Mountain Spring Zone
• River mile 19.5–21 at start of Winograd (1959) accretion zone
• Abundant discrete springs, large spring zones, and seepage faces
along both banks and in channel
• Vents typically 5–15 ft above river with discharge from
<1 to 100s of gpm
• Discharge increases downstream to Lava Tube spring
(13 cfs, 6000 gpm) at the Gorge fault
Bear Crossing-Felsenmeere Spring Zone
TC-72
Taos
Plateau
recharge
Arsenic
springs
Upper
Taos Box
+57 cfs
Gains in Rio Grande stream flow emanate from groundwater discharge
from aquifers west (Taos Plateau) and east (Sunshine Valley) of
the gorge via large springs and spring zones. Two principal spring
zones—Ute Mountain and the Bear Crossing-Felsenmeere—coincide
with the Ute Mountain and Red River fault zones.
TC-204
Ezequiel
4900 rcybp
Brushy-Timber
Mountain Horst
0.22 TU
34 yrs (CFC-12)
7000
-90
Large playa located at east end of a closed basin in the center of the Taos Plateau was filled by
snowmelt and rainwater in May of 2008.
TC-234
Schofield
8180 rcybp
0.09 TU
Bear Crossing
Felsenmeere TS-8
spring zone
TS-61
Modified from Bauer etal (2007) and Kinslie etal (2011 in review)
Chloride
G
Chiflo trail
Cerro gage
Red River
6500
TC-221
No Agua
6520 rcybp
0.02 TU
Chiflo springs
R.G east side
Sunshine
Valley
7000
Red River fault
zone
2
1
Lee trail
Latir Creek
Chiflo
springs
EAST
TS-113 (Lava Tube Spring)
3840rcybp
0.1 TU
41 yrs (CFC-12)
7500
20
E’
Costilla
Questa
Basin
40
Ca
m
siu
rbo
285
9000
TC-218
(Alire)
8030 rcybp
0.04 TU
35 yrs (CFC-12)
Brushy-Timber
Mountain
Horst
Rio Grande Gorge
Mixing line
with projected
end member
Taos Plateau
Rio Grande Gorge
Gu
we adalu
lls
and pe M
m
spr ounta
ing
s in
2
TS
TC -8
-20
4
TC
-21
San Antonio Mtn.
WEST
100
nat
e
m
siu
E
lf
Su
gne
Sunshine
Valley
-13 cfs
35
3
tas
Ma
Undivided Proterozoic
0
Po
40
Older Andesites (Miocene or Pliocene)
10,000
2
m+
diu
So
60
San Antonio Mountain
perched aquifer
20
0
80
Older Tertiary rocks (Oligocene)
1 2 3
4
0
1
Guadalupe Mountain well
Servilleta Basalt (Pliocene)
Vertical Exaggeration = 8x
te
ulfa
+S
Ch
lor
100
Hinsdale Formation and related rocks
Rio Grande stream water
m
0
Dacite of San Antonio Mountain (Pliocene)
Sunshine springs
R.G east side
30
40
20
Taos Plateau well, CO
Rio San Antonio stream water
u
esi
40
Amalia Tuff (Oligocene)
Arsenic springs
gn
Ma
ide
m+
lciu
60
Taos Plateau well, NM
Xenocrystic basaltic andesite (Pliocene)
Site number
Apparent 14C age
Tritium content
CFC-12 recharge age
Rio Grande Gorge spring
Ca
60
Santa Fe Group (Miocene to Pliocene)
25
80
80
Alluvium, undivided (Pleist. to Holocene)
-13
-12
View west of the eastern flanks of San Antonio Mountain.
ACKNOWLEDGEMENTS
We thank Rolf Schmidt-Petersen of the New Mexico Interstate Stream Commission for arranging the principal funding
for this study. Trudy and Ed Healy provided a grant from the
Healy Foundation for an overlapping study of the adjacent
Rio Grande gorge springs. The funding and project planning
were facilitated by the efforts of Ron Gardiner of Questa. We
are especially indebted to Herb Chavez, James Harmon, and
Stuart Smith (BLM, Taos Field Office) for invaluable assistance in finding, measuring, and sampling the BLM wells on
the Taos Plateau. Mark Sundin (BLM, Taos Field Office)
assisted with several aspects of the project. Ron Gervason and
Tony Benson of the Taos Soil & Water Conservation District
provided UTM locations of inventoried water wells in the
study area. Ren Thompson (USGS, Denver) was kind enough
to review the geologic cross sections and share his expertise
on the geology of the northern Taos Plateau. Andrew Cambell generously reviewed isotopic and geochemical aspects
of the study. Hamilton Brown and Jeff Ogburn collected
winter tributary stream-flow samples for geochemical
analyses. Finally, we are much obliged to the land owners
and permittees who graciously allowed us access to their
wells for water level measurements and sampling.
• River mile 33–34 where Red River
fault zone intersects gorge
• Discharge from vents beneath basalt talus 50 to 100 ft or more
above west bank
• Bear Crossing Qtot ≈ 6400 gpm (14 cfs)
• Felsenmeere Springs Qtot ≈ 9700 gpm (21.6 cfs)
• High discharge reflects high river gradient (84 ft/mi) and deep
incision through Upper Taos Box
GIS/CARTOGRAPHY/LAYOUT: Brigitte Felix, The New Mexico Bureau of Geology & Mineral Resources