A 200 kyr record of lake-level change from
the Carrizo Plain, Central Coastal California
R. Negrini, T. Miller, R. Stephenson, R. Ramirez, J. Leiran, D. Baron, P. Wigand, CSU Bakersfield
D. Rhodes, Georgia Southern University
T. Algeo, University of Cincinnati
pasadena.wr.usgs.gov/ office/galetzka/imgbank/
• Testing climate models with records from closed lakes
• Soda Lake in the Carrizo Plain
• Geomorphic setting and previous work
• Initial results
• Coring
• Lithology
• Magnetic susceptibility
• SEM petrography
• Age control
• XRD of evaporate minerals
• Work in progress
• Spectral gamma logs
• Charcoal and pollen counts
• Coring South Basin for youngest part of record
pasadena.wr.usgs.gov/ office/galetzka/imgbank/
Lake-record contributions:
Milankovitch Time-Scales (104-106 yr)
N
after Benson
(2004)
Lake-record contributions:
0
Milankovitch Time-Scales (104-106 yr)
Inferred depth
SPECMAP OIS (arbitrary units)
100
Age (Ka)
200
300
400
500
600
polar
ice volume
deeper
GSL
Lake-record contributions:
Milankovitch Time-Scales (104-106 yr)
Owens Lake Paleoprecipitation Record
polar ice volume
Sierran precipitation
from Smith et al. (1997)
Lake-record contributions:
Milankovitch Time-Scales (104-106 yr)
W. W. Norton. After Flint, 1971
Millennial Time-Scales (104-106 yr)
GISP2 Ice Core δ18O (o/oo)
20
25
GISP2 Age (Ka)
Lake-record contributions:
30
-44
-42
H2
-40
-38
-36
IS #3
4
H3
5
6
35
7
H4
40
8
9
10
11
45
H5
50
12
Warmer North Atlantic
Lake-record contributions:
Post-LCM millennial
scale climate
features in Owens
Lake core (from
Benson et al., 1997)
Millennial Time-Scales (104-106 yr)
Lake-record contributions:
GISP2 Ice Core δ18O (o/oo)
20
GISP2 Age (Ka)
25
30
-44
-42
H2
-40
-38
B&B Core Inclination (˚)
0
-36
90
4
H3
6
35
7
H4
6
9
H5
12
1
50
LE
9
10
40
11
45
12
MSH Cy Ash
10
100
Summer Lake B&B Core IRM (A/m)
Warmer North Atlantic
35
8
8
10
11
45
MLE
7
25
30
Wono
Ash
5
20
high 36Cl in
GISP2 core
3
4
IS #3
5
40
Millennial Time-Scales (104-106 yr)
Deeper Summer Lake
50
magnetic excursions
in Summer Lake Core
Lake-record contributions:
Great Basin response to
cold temperatures in the
North Atlantic
North Pacific SSTs
decrease in response to
lower temperatures in
North Atlantic
(Mikolajewicz, et al. 1997). Millennial Time-Scales (104-106 yr)
Climate Change on Millennial Time-Scales (103-104 yr)
Pluvial Lakes of the Western U.S. (after Benson, 2004)
N
Location of Soda Lake relative to the Santa Barbara Basin
OL
TL
SL
SBB
BL
pasadena.wr.usgs.gov/ office/galetzka/imgbank/
Soda Lake in the Carrizo Plain, San Luis Obispo County, CA
South
Basin
North
Basin
N
J. Shelton
Geomorphic features relevant to past lake levels
trimmed
ridges
N
slickspots
South
Basin
active clay dune (lunette)
North
Basin
Carrizo Plains?
N
Geomorphic evidence for
17m variation in lake depth
Eigenbrode (1999) Coring Site in South Basin
SLC-SB
Eigenbrode (1999) Core analyses
Lithology and geochemistry study of <2 m
core representing late Holocene
Lake Flat Coring Sites of Present Study
SL-1
• 4 m core
• auger flight samples to 14 m SLC-SB
Lake Flat Coring Sites of Present Study
SL-1
• 4 m core
• auger flight samples to 14 m NSL-1
SLC-SB
40 m core
Recovery data for 40 m NSL-1 Core
(recovery ~80%)
Core Drive
NSL-1A-1
NSL-1A-2
NSL-1A-3
NSL-1A-4
NSL-1B-2
NSL-1B-3
NSL-1B-4
NSL-1B-5
NSL-1B-6
NSL-1B-7
NSL-1B-8
NSL-1B-9
NSL-1B-10
NSL-1B-11
NSL-1B-12
NSL-1B-13
NSL-1B-14
NSL-1B-15
NSL-1B-16
NSL-1B-17
NSL-1B-18
NSL-1B-19
NSL-1B-20
NSL-1B-21
NSL-1B-22
NSL-1B-23
NSL-1B-24
*Top Cum Depth
of **top of core Length of
liner bgs (m)
liner (m)
0.22
1.44
3.30
4.82
6.32
7.84
9.36
10.89
12.41
13.94
15.46
16.99
18.51
20.03
21.56
23.08
24.61
26.13
27.66
29.18
30.71
32.23
33.75
35.28
36.80
38.33
39.85
Dpth below
liner top to
top of
sediment
(cm)
Dpth above
liner bott to
bott of
sediment
(cm)
***Top Cum
Depth of top of
sediment in
core (m)
Cum Depth of
bottom of
sediment in
core (m)
Total thickness
of intact core
(m)
1.20
1.52
0.96
1.52
0.58
1.35
1.10
1.52
1.52
1.52
1.52
1.52
1.52
0.59
1.52
1.52
0.72
1.52
1.52
1.52
1.52
1.20
1.52
0.11
0
0.04
0.19
0.05
0.04
0.03
0
0
0
0
0
0
0.02
0
0
0.1
0
0
0
0
0
0
0
0
0
0.01
0
0
0.02
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.01
0
1.55
3.30
4.86
6.51
7.89
9.40
10.92
12.41
13.94
15.46
16.99
18.51
20.03
21.58
23.08
24.61
26.23
27.66
29.18
30.71
32.23
33.75
35.28
2.64
4.82
5.78
7.83
8.42
10.71
11.97
13.93
15.46
16.98
18.51
20.03
21.55
22.15
24.60
26.13
26.85
29.18
30.70
32.23
33.75
34.94
36.80
1.09
1.52
0.92
1.32
0.53
1.31
1.05
1.52
1.52
1.52
1.52
1.52
1.52
0.57
1.52
1.52
0.62
1.52
1.52
1.52
1.52
1.19
1.52
1.52
0
0
38.33
39.85
1.52
Oxidized Lithology
• light olive-brown (5Y 6/4)
• 1-10 mm, euhedral, gypsum xtals common
• microscopic gypsum xtals in clay matrix
• relatively high magnetic susceptibility (κ=20-60 cgs units)
• massive
• pollen preservation very poor throughout core
• 10-20 µm charcoal ubiquitous
• no diatoms
Reduced Lithology
• dark gray (5Y 4/1); greenish gray (10Y or 10GY 5/1) • 1-10 mm, euhedral, gypsum xtals Uncommon; sometimes in
discrete layers
• microscopic gypsum xtals in clay matrix
• very low magnetic susceptibility (κ<20 cgs units)
• massive
• pollen preservation very poor throughout core
• 10-20 µm charcoal ubiquitous
• no diatoms
Reduced/oxidized lithology = deep/shallow lake or vice-versa?
Initial hypothesis can be developed using distribution of
lithologies throughout core and initial ages. Can do this easily
120
Whole-core magnetic susceptibility log of 40m Soda Lake core
100
80
x10E-6
magnetic susceptibility (cgs units)
because κ is proxy for lithology.
60
40
20
0
0
10
20
30
depth (m)
40
50
Reduced/oxidized lithology = deep/shallow lake or vice-versa?
Initial hypothesis can be developed using distribution of
lithologies throughout core and initial ages. Can do this easily
120
Whole-core magnetic susceptibility log of 40m Soda Lake core
100
80
x10E-6
magnetic susceptibility (cgs units)
because κ is proxy for lithology.
60
40
20
0
0
10
20
two prominent reduced zones
30
depth (m)
40
50
Magnetic susceptibility contrast across boundary between
oxidized and reduced sediments
magnetic susceptibility (cgs units)
bottom core NSL-1B-8
60
50
40
30
lower reduced zone
20
10
0
16.25
16.5
16.75
depth (m)
17
17.25
1-50 µm magnetite easily identified in oxidized sediments; none
observed in reduced sediments
bottom core NSL-1B-8
Mt
Mt
Mt
Mt
Gp
Cu minerals
Copper minerals occasionally observed in reduced sediments
1 cm
gypsum
Cu minerals
Electron microscopy of Copper minerals
gypsum
gypsum
Quantitative results
80
60
Weight%
40
%
20
0
C
O
Si
S
Cl Ca Cu
Initial age control of new core
x10E-06
?
SL-1A Core
(1m higher elevation due
to post-depositional tilting)
NSL-1 Core
Initial age control of new core
x10E-06
?
20.2-22.0 cal Kyr on charcoal
(17.74 ± 0.33 14C Kyr)
SL-1A Core
(1m higher elevation due
to post-depositional tilting)
NSL-1 Core
Initial age control of new core
x10E-06
?
20.2-22.0 cal Kyr on charcoal
*
SL-1A Core
(1m higher elevation due
to post-depositional tilting)
NSL-1 Core
*22.5 cal Kyr on seed pods
(19.09 ± 0.08 14C Kyr)
Seed pods of Scirpus Maritimus(?) (alkali bulrush) found in 1 cm-thick
layer within upper zone of reduced sediments. Ostracodes also
common in this layer.
Initial age control of new core
x10E-06
?
20.2-22.0 cal Kyr on charcoal
*
SL-1A Core
(1m higher elevation due
to post-depositional tilting)
NSL-1 Core
*22.5 cal Kyr on seed pods
(19.09 ± 0.08 14C Kyr)
Preliminary climate model
x10E-06
?
20.2-22.0 cal Kyr on charcoal
MIS 2
*
SL-1A Core
(1m higher elevation due
to post-depositional tilting)
NSL-1 Core
MIS 5?
*22.5 cal Kyr on seed pods
MIS 6?
(19.09 ± 0.08 14C Kyr)
Preliminary climate model
x10E-06
?
20.2-22.0 cal Kyr on charcoal
MIS 2
*
millennial-scale
lake-level changes?
MIS 5?
*22.5 cal Kyr on seed pods
MIS 6?
(19.09 ± 0.08 14C Kyr)
Whole core susceptibility values were near sensor sensitivity limit
magnetic susceptibility (cgs units)
bottom core NSL-1B-8
60
50
40
30
lower reduced zone
(MIS 6?)
20
10
0
16.25
16.5
16.75
depth (m)
17
17.25
Magnetic susceptibility of box samples
discrete sample
measurements
Refined hypothesis: MIS6(?) lake deepens up until Termination
whole core
measurements
Testing the refined hypothesis: evaporite
mineralogy
peak criteria = large amplitude,
little overlap with other peaks,
good regression stats
Testing the refined hypothesis
discrete sample
measurements
spectral
gamma
log data
Pollen, etc. found in NSL-1A-3 core drive
juniper
charcoal
artemisia
pinus
atriplex
blue-green algae
Late Pleistocene through Holocene record from South Basin
N
South
Basin
Late Pleistocene through Holocene record from South Basin
N
South
Basin
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Conclusions
•  Lake-level proxies are consistent and suggestive of both
Milankovitch- and millennial-scale responses
•  Dateable material is present
•  Pollen and charcoal are present in high enough
concentrations to provide more straightforward estimates
of paleoclimate
•  Record potentially covers past 200 kyr including Holocene
•  Proximity to ocean cores and likely sensitivity (closed
basin lake) suggests that record will contribute
significantly to our understanding of marine/nonmarine
climate linkages in western NAm
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Acknowledgments
• NSF Grant #030332 OEDG Program
• Kathy Sharum and Rhonna Hurl, BLM
• Chevron, USA REVS Up Program
• High School Teachers and Students of REVS Up Program
• Elizabeth Powers and Tom Osborn, CSUB Technicians
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