| DESCRIPTION OF MAP UNITS |
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| Alluvium and related deposits; glacial deposits |
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Recent Alluvium |
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Colluvium |
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Lacustrine deposits |
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Sand dunes |
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Older alluvium |
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Fan deposits |
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Colluvium and glacial drift, undivided |
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Landslide |
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Talus |
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Older lacustrine deposits |
| Tioga glacial deposits |
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Till |
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Outwash deposits |
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Ponded deposits |
| Tahoe glacial deposits |
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Till |
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Outwash deposits |
| Donner Lake glacial deposits |
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Drift |
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Outwash deposits |
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| Truckee River Formation |
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Cinder cone deposits |
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Trachyandesite of Tahoe City |
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Tahoe City basalt |
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Trachybasaltic andesite flow of Deer Creek |
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Olivine basalt of Lake Forest |
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Juniper Flat alluvium |
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Prosser Creek alluvium |
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Hirschdale basalt |
| Trachyandesite and dacite flows and domes of Dry Lake |
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Unit 4, youngest |
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Unit 3 |
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Unit 2 |
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Unit 1, oldest |
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Bald Mountain basalt |
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Olivine basalt flows, undivided |
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Olivine basalt flows of Page Meadow |
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Olivine basalt flows of Polaris |
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Olivine basalt flows of Burton Creek |
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Fluvial sand and gravel of Cabin Creek |
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Olivine basalt of Alder Hill |
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Trachyandesite flows of Agate Bay |
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Volcaniclastic rocks of Skylandia |
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Trachyandesite flows of Cedar Flat |
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Trachyandesitic plug |
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Fir Crags gravel |
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| Mehrten Formation |
| Squaw Peak member |
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Basalt flows |
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Basaltic andesite flows |
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Andesitic intrusions, plugs, and dikes |
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Biotite-hornblende andesite domes and flows |
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Biotite-hornblende andesite intrusions |
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Block and lapilli tuff breccia of Mt. Disney |
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Stratified volcaniclastic deposits |
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Volcaniclastic deposits, undivided |
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Pyroxene andesite flows |
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Hornblende andesite flows |
| Martis Peak member |
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Aphyric or microporphyritic andesite lava flows |
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Andesitic intrusions, plugs, and dikes |
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Andesitic volcaniclastic deposits |
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Basaltic andesite flows |
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Pyroxene andesite flows |
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Hornblende andesite flows |
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Hornblende andesite intrusion |
| Mt. Lincon member |
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Basalt lava flows |
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Basaltic tephra |
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Intrusive plugs and dikes |
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Andesite lava flows, undivided |
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Andesite lava flows, aphyric |
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Hornblende andesite lava flows |
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Hornblende andesite intrusion |
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Pyroxene andesite flows |
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Basaltic andesite flows |
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Diabase intrusion |
| Fluvial strata intercalated with Tlp and Tllt |
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Undivided |
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Youngest |
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Intermediate |
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Oldest |
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Volcaniclastic rocks, undivided |
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Lapilli tuff breccia |
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| Valley Springs Formation |
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Rhyolite tuff, undivided |
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Nine Hill Tuff |
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Rhyolite tuff |
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Mickey Pass Tuff |
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Tuff of Campbell Creek |
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Tuff E |
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Rhyolite tuff |
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Tuff of Sutcliffe |
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Rhyolite tuff of Rattlesnake Canyon |
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| Granitic Rocks |
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Hornblende-biotite granodiorite of Summit Lake |
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Hornblende-biotite granodiorite with K-spar megacrysts diorite |
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Tonalite of Lake Mary |
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Granodiorite |
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Hornblende-biotite granodiorite, undivided |
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Quartz monzonite, undivided |
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| Lake Tahoe Sequence of Harwood (1992) |
| Ellis Peak Formation |
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Quartz arenite |
| Blackwood Formation |
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Sandy limestone and pelitic hornfels |
| Onion Creek Formation |
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Marble and calc-silicate hornfels |
| Serena Creek Formation |
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Biotite schist |
| Picayune Valley Formation |
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Chert and quartz-rich conglomerate, quartzose sandstone, and pelitic hornfels. |
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Gneiss of unknown affinity |
| MAP SYMBOLS |
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Contact between map units - Solid where
accurately located, dashed where approximately
located; short dash where inferred; dotted where
concealed; queried where uncertain. |
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Contact separating individual lava flows within the same map unit. |
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Fault - Solid where accurately located, dashed
where approximately located; short dash where
inferred; dotted where concealed; queried where
uncertain. Ball and bar on downdropped block. |
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Landslide scarp |
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Moraine crestline, approximately located |
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Dike |
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Dike intruding fault |
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Hydrothermal alteration; boundary approximately located. |
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Inclined Bedding |
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Horizontal bedding |
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Inclined foliation |
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Vertical foliation |
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Strike and dip of inclined cleavage |
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Location and number of radiometrically dated rock sample. Age data are presented in
Tables 1 and 2 in the accompanying pamphlet. |
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