Evolution of the northwestern margin of the Basin and RangeInsights from new geologic mapping in northeastern California
Egger, Anne E.1 ([email protected]) and Colgan, Joseph P.21 GES Department, Stanford University, Stanford, CA 94305 2 U.S. Geological Survey, Menlo Park, CA 94025
Session 105208
Key features • Rock units exposed in the map area record volcanic activity from late Eocene through the Pliocene with a peak in subduction-related volcanism ~26-27 Ma
• All units vary laterally in thickness over relatively short distances (a few kilometers)
• Oligocene and Miocene volcanic edifices built upon each other, indicating the persistence of significant topographic relief
• Both mid-Miocene and late Miocene basalt flows are locally derived, and never extended over the entire map area
• Mid-Miocene lava flows are fed by N-S-oriented dikes and cut by N-S-oriented normal faults
• Late Miocene lava flows flowed into fault-bound basins and are cut by a later series of N-S-oriented normal faults
• The Surprise Valley changes from a full graben in the southern portion of the map area to a half-graben in the north, with a complex of buried horsts and grabens in the intervening region
Today
5 Ma
10 Ma
15 Ma
20 Ma
25 Ma
30 Ma
35 Ma
40 Ma
Deposition of volcaniclastic sediments in alluvial plain, being shed off andesitic volcano ~20 km SSW of map area (Egger et al, 2009). Possibly an intra-arc extensional basin.
Development of andesitic stratovolcano centered near Cedar Pass, including shallow intrusives and ignimbrites, characteristically rich in hornblende.
Development of subduction-related ba-saltic shield volcano; up to 2 km of basalt flows, breccias, and mafic tuffs centered near Solider Creek.
Development of Hays Volcano and thin basalt flows capping Cedar Pass complex.
SU
BD
UC
TIO
NT
RA
NS
ITIO
NE
XT
EN
SIO
N
Development of numerous basaltic volca-noes, many still evident in topography today. Feeder dikes suggest some E-W-directed extension at this time; flows are transitional between arc-related and low-K olivine tholeiites.
Extension, horst-and-graben normal faulting
Extensive silicic volcanism, including eruption of Alturas tuff and numerous ob-sidian domes, possibly related to New-berry volcanic trend.
Widespread flows of low-K olivine tholei-ites (LKOTs), thin basalt flows layered with tuffs, tuffaceous sediments, and lake sedi-ments. Localized flows fill topography
Extension, focus of uplift on the Surprise Valley Fault, many small faults cut LKOTs
Paleoseismology reveals moderate rate of slip along the Surprise Valley Fault in the Quaternary (Personius et al, 2009)
Axelrod, D.I., 1966, Potassium-argon ages of some western Tertiary floras: American Journal of Science, v. 264, p. 497-506.
Carmichael, I.S.E., Lange, R.A., Hall, C.M., and Renne, P.R., 2006, Faulted and tilted Pliocene olivine-tholeiite lavas near Alturas, NE California, and their bearing on the uplift of the Warner Range: Geological Society of America Bulletin, v. 118, p. 1196-1211.
Duffield, W.A., and McKee, E.H., 1986, Geochronology, structure, and basin-range tectonism of the Warner Range, northeastern California: Geological Society of America Bulletin, v. 97, p. 142-146.
Duffield, W.A., Weldin, R.D., and Davis, W.E., 1976, Mineral resources of the South Warner Wilderness, Modoc County, California: U. S. Geological Survey Bulletin, v. B1385, p. 31.
Egger, A.E., Colgan, J.P., and York, C., 2009, Provenance and palaeogeographic implications of Eocene-Oligocene sedimentary rocks in the northwestern Basin and Range: International Geology Review, v. 51, p. 900 - 919.
Hedel, C.W., 1984, Maps showing geomorphic and geologic evidence for late Quaternary displacement along the Surprise Valley and associated faults, Modoc County, California, Miscellaneous Field Studies Map: Reston, VA, U. S. Geological Survey.
Lerch, D.W., Klemperer, S.L., Glen, J.M.G., Ponce, D.A., Miller, E., and Colgan, J., 2007, Crustal structure of the northwestern Basin and Range Province and its transition to unextended volcanic plateaus: Geochemistry Geophysics Geosystems, v. 8, p. 1-21.
Personius, S.F., Crone, A.J., Machette, M.N., Mahan, S.A., and Lidke, D.J., 2009, Moderate rates of late Quaternary slip along the northwestern margin of the Basin and Range Province, Surprise Valley fault, northeastern Califor-nia: J. Geophys. Res., v. 114.
Mapping in the South Warner Wilderness done by Duffield et al, 1976
-4
0
-2
2
4
3
1
-1
-3
-4
0
-2
2
4
3
1
-1
-3
Distance (km)
Dep
th (k
m)
0 20 4084 12 16 24 363228 56524844
Ben
d in
sec
tion
Ben
d in
sec
tion
Ben
d in
sec
tion
Ben
d in
sec
tion
Ben
d in
sec
tion
Tcp
TsccTsbn
Tmrv
Tdc
Tsc
Tlw
B-B'C-C'D-D'
-4
0
-2
2
4
3
1
-1
-3No vertical exaggerationScale 1:100,000
NS
A–A'
-4
0
-2
2
4
3
1
-1
-3
Distance (km)
Dep
th (k
m)
0 20 4084 12 16 24 363228 524844-4
0
-2
2
4
3
1
-1
-3
D–D'
No vertical exaggerationScale 1:100,000
W E
-4
0
-2
2
4
3
1
-1
-3
Distance (km)
Dep
th (k
m)
0 20 4084 12 16 24 363228 524844-4
0
-2
2
4
3
1
-1
-3
C–C'
No vertical exaggerationScale 1:100,000
W E
B–B'
Distance (km)
No vertical exaggerationScale 1:100,000
Dep
th (k
m)
0 20 4084 12 16 24 363228 524844-4
0
-2
2
4
3
1
-1
-3
-4
0
-2
2
4
3
1
-1
-3
W E
5
5
5
5
8
7
8
3
3
5
7
8
9
7 8
5
7
2
5
22
15 15
25
30
25
30
10
12
13
10
13
15
10
1915
1518
10
12
10
12
10
10
20
15
20
25
30
25
3525
20
15
1025
20
13
20
20
20
25
17
25
20
25
1518
25
25
15
10
1012
16
28
15
25 1520
2120
15
20
24
11 14
19
20
24
23
17
14
14
14
12
2515
18
10
14
10
10
30
15
20
10
18
19
28
22
26
23
20
24
2628
19
18
2219
241616
20
13
25
22
2215
18
26
23
2510
15
2522
17
15
15
13
10
20
10
22 25
10
20
25
25
24
18
10
10
2615
18
27
17
261525
30
20
22
30
25
20
2522
28
25
12
10
2215
34
10
11
1210
1310
10
70
78
64
60
6155
70
55
75
8072
80
70
80
75
57
54
75
65
A'
A
B
B'
D'
C'
D
C
Ti
TcpTlb
Qal
Tat
Tcp
Tat
Tlb
Qf
Qc
Ti
Ti
Ti
Ti
Tsc
Qls
Qls
Tsu
Tdc
Tdc
Qal
Tlb
TatQal
Tat
Tat
Tlb
Tat
Trt
Tmb
Tlw
Tcp
Tat
Tlb
Qof
Tat
Qof
Qpd
Tsbn
Tscc
Tmrv
Tmt
Tmr
Tcp
Tmb
Tmt
TmbTmr
Tlb
Tlb
Trt
Tmba
Tmba
Qp
Qf
Qf
Qp
Qe
Qal
Qpd
Qal
Qal
Qls
ThvTlw
Tdc
Tsu
Qpd
Qoa
Qpd
Qpd
Qpd
Tmv-u
Qp
Qe
Qc
Qe
Qe
Qp
Qal
Qal
Tcp
Tmb
Tmb
Qls
Qls
Qls
Qpl
Qpl
Qls
Qols
Qols
Qpl (?)
Qe
Qe
Qe
Qf
Qf
Qe
Qe
Ql
Qc
QeQp
Qal
Tlb
TmbQpb
Qpl
Tlb
Tmr
Tmr
Tlb
Tts
Tts
Qpl (?)
Ti
Qc
Qc
Qc
Qf
Qf
Tsc
Qal
Tbm
Tlb
Tat
Tlb
Qal
Qpl
QplQoa
Tcp
Tlb
Tlb
Qof
Qal
Qof
QalQc
Tmr
Tlb
TlbTlb
Tmt
Tcp
Qc
7.3 ± 0.3 Ma
27.46 ± 0.61 Ma
27.50 ± 0.21 Ma
26.42 ± 0.05 Ma
26.6 ± 1.1 Ma
3.98 ± 0.06 Ma
14.57 ± 0.08 Ma
2.76 ± 0.2 Ma
14.5 ± 0.4 Ma
23.91 ± 0.13 Ma
15.44 ± 0.17 Ma
15.53 ± 0.11 Ma
25.4 ± 1 Ma
14.1 ± 0.4 Ma
14.1 ± 0.4 Ma
15.7 ± 0.5 Ma15.8 ± 0.5 Ma
33.9 ± 2.7 Ma
26.3 ± 1 Ma
17.3 ± 0.6 Ma
31.1 ± 1.3 Ma
3.84 ± 0.06 Ma
19.22 ± 0.27 Ma
28.8 ± 1.1 Ma
4.28 ± 0.16 Ma
4.36 ± 0.13 Ma
26.54 ± 0.08 Ma
30.02 ± 0.52 Ma
27.07 ± 0.22 Ma
26.26 ± 0.13 Ma
15.15 ± 0.55 Ma
40.8 ± 3 Ma
8.08 ± 0.09 Ma
5.95 ± 0.08 Ma
4.33 ± 0.08 Ma
27.17 ± 0.33 Ma
26.53 ± 0.06 Ma25.76 ± 0.06 Ma
26.82 ± 0.08 Ma
26.64 ± 0.08 Ma
26.04 ± 0.06 Ma
24.18 ± 0.34 Ma
120°0'0"W120°10'0"W120°20'0"W
41°4
0'0"
N41
°30'
0"N
41°2
0'0"
N
0 2 4 6 8 101km
395
395
139
299
140
140
31
447
139
299
Vya
Adel
Plush
Likely
Alturas
Madeline
Lakeview
FortBidwell
GooseLake
LakeAbert
EagleLake
CrumpLake
Clear LakeReservoir
Warner R
ange
Crustal refraction line
OREGONCALIFORNIA
NEVADAOREGON
Har
t M
ount
ain
War
ner
R
im
Hays C
anyon R
ange
119°0'0"W120°0'0"W121°0'0"W
42°3
0'0"
N42
°0'0
"N41
°30'
0"N
41°0
'0"N
40°3
0'0"
N
0 10 20 30 40 50km
Seismicity(magnitude)
2.0 - 2.9
3.0 - 3.9
4.0 - 4.9
>5.0
Normal fault
Surprise Valley Fault B
lack Rock R
ange
SheldonPlateau
ModocPlateau
Granite R
ange
Calico
Mo
untains
Gerlach
15
Dike
Geochronology
Symbols
Strike and dip of bedding
Horizontal bedding
Volcanic vent
Normal fault
Contact
Normal fault, concealed
Map units
Qal
Qf
Qc
Qe
Qhs
Ql/Qp
Qls
Qoa
Qof
Qols
Qpb
Qpd
Qpl
Tlb
Tts
Tmr
Tat
Tmba
Tmt
Tmb
Trt
Tmv-u
Tbm
Tcp
Ti
Thv
Tsc
Tlw
Tdc
Tscc
Tsbn
Tsu
Tmrv
Holocene sediments Oligocene volcanic rocks
Oligocene sedimentary rocks
Eocene rocks
Late Miocene volcanic rocks
Mid-Miocene volcanic rocks
Pleistocene sediments
Alluvium
Fan deposits
Bald Mountain basalt
Cedar Pass volcanic complex
Intrusive rocks of Cedar Pass complex
Hays Volcano
Soldier Creek volcanics*
Lost Woods Formation*
Deep Creek Formation*
Steamboat Formation, Cougar Cliffs member*
Steamboat Formation, Badger’s Nose member*
Oligocene sedimentary rocks, undifferentiated
McCulley Ranch Formation*
Low-K olivine tholeiitic basalts
Tuffs and tuffaceous sediments
Late Miocene rhyolites
Alturas tuff
Basalt and andesite flows
Tuff and reworked tuff
Basalt flows
Rhyolitic and andesitic ash flow tuffs
Early Miocene volcanic rocks
Mid-Miocene volcanic rocks, undifferentiated
Colluvium
Eolian deposits (sand dunes)
Hot spring deposits
Lake and playa deposits
Landslides
Older alluvium
Older fan deposits
Older landslide deposits
Pleistocene beach gravels of Lake Surprise
Pleistocene deltas of Lake Surprise
Pleistocene lake sediments of Lake Surprise
Strike and dip of fault plane70
Holocene fault scarp (Hedel, 1984)
this study
Carmichael et al., 2006
Duffield and McKee, 1986
Axelrod, 1966* names from Martz, 1968
Regional setting:The edge of extension
Along the northwestern margin of the Basin and Range province, slip on the Sur-prise Valley Fault has resulted in the uplift of the Warner Range. New geologic map-ping in the Warner Range and surrounding region documents a complex history of volcanism and extension from the Eocene to the present, recorded by volcanic rock units that display significant variability in their distribution, along-strike stratigraphic thickness, and their relationship to normal faults and pre-existing topography.
At the base of the range, a late Eocene to early Oligocene (34-31 Ma) volcaniclastic alluvial sandstone and conglomeratic sequence is exposed for about 25 km along strike, decreasing in thickness from 1500-200 m south to north. These rocks are overlain by a series of overlapping volcanic edifices that record Oligocene arc vol-canism from 28–24 Ma. In the southern part of the range, Oligocene volcanic rocks are unconformably overlain by Miocene (19–12 Ma, predominantly 16–14 Ma) tuffs and locally-sourced mafic lava flows. Mid-Miocene rocks were never present in the northern part of the range, however, where the Oligocene rocks are directly overlain by late Miocene (10–7 Ma) rhyolite flows.
The modern profile and elevation of the Warner Range thus includes a large com-ponent of “original” topography. Although high elevations (<3000 m) in the central Warner Range (Warren Peak) correspond to the greatest stratigraphic throw on the Surprise Valley Fault, the southern Warner Range (Eagle Peak) sits at a similar el-evation, despite significantly less throw on the fault there, due to substantial Mio-cene volcanic edifices in the footwall.
On the west side of the Warner Range, the ~11 Ma Alturas tuff and ~3-7 Ma basalt flows appear to have been deposited in pre-existing topography developed in part through motion along normal faults. These flat-lying units are also cut by faults, however, suggesting at least two episodes of faulting: one between 14 and 11 Ma and one after 3–4 Ma. Pliocene basalt flows are also present east of the Warner Range, where they dip 10-15° west and are cut by numerous normal faults. Despite the similarity of these basalt flows on either side of the range, new mapping indi-cates they never formed a continuous sheet and thus cannot be used to calculate the total offset and long-term slip rate along the Surprise Valley Fault.
Abstract
Geology of the Warner Range
Evolution of the margin
Velocity model along crustal refraction line shown above, from Lerch et al., 2007. Note thinning of crust from ~36 km to ~30 km across the profile. SV = Surprise Valley.
Regional map of the northwestern margin of the Basin and Range, including seis-micity from 1875 to 2008 (historical earthquakes from California Division of Mines and Geology; 1973 to present from USGS/NEIC). Crustal refraction line from Lerch et al., 2007.
References