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Geologic map of the Lake Tahoe Basin

Geologic map of the Lake Tahoe Basin

California Geological Survey, Regional Geologic Map No. 4, 1:100,000 scale

Compiled by: George J. Saucedo


Digitized by: Jason D. Little, Sarah E. Watkins, Jennifer R. Davis, Marina T. Mascorro, Victoria D. Walker and Eric W. Ford

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Artificial fill (late Holocene) 
Beach deposits (Holocene) 

Flood-plain deposits (Holocene) 
Talus deposits (Holocene) 
Lake deposits (Holocene) 
Younger glacial deposits (Holocene) 
Colluvium (Holocene) 
Landslide deposits (Holocene and Pleistocene) 
Alluvium (Holocene and Pleistocene) 
Alluvial fan deposits (Holocene and Pleistocene) 
Mudflow deposits (Holocene and (or) Pleistocene) 
Older beach deposits (Pleistocene) 
Older lake deposits (Pleistocene) 
Lacustrine terrace deposits (Pleistocene) 
Tioga glacial deposits (Pleistocene) 
Outwash deposits 
Tahoe glacial deposits (Pleistocene) 
Outwash deposits 
Tahoe and Tioga glacial deposits - undivided (Pleistocene) 
Older glacial deposits - pre-Tahoe deposits (Pleistocene) 
Outwash deposits 
Glacial deposits undivided (Pleistocene and Holocene?) 
Outwash deposits 
Bald Mountain olivine latite of Birkeland (1961) (Pleistocene)
Qvbmcc - cinder cone deposits
Juniper Flat alluvium of Birkeland (1961) (Pleistocene)
Prosser Creek alluvium of Birkeland (1961) (Pleistocene) 
Hirschdale olivine latite of Birkeland (1961) (Pleistocene)
Qvhcc - cinder cone deposits; Qvht - basaltic tuff
Older talus deposits (Pliocene and (or) Pleistocene)
Dry Lake volcanic flows of Birkeland (1961); Wise and Sylvester (2004)QPvd (Pliocene and (or) Pleistocene) - QPvd1 - QPvd4 (oldest to youngest) 
Big Chief basalt of Birkeland (1961) (Pliocene and (or) Pleistocene) 
Page Meadow basalt of Wise and Sylvester (2004) (Pliocene and (or)QPvpm Pleistocene) 
Unnamed gravels, sand and alluvium (Pliocene and (or) Pleistocene) 
Burton Creek basalt of Wise and Sylvester (2004) (Pliocene and (or)QPvbu Pleistocene) 
Lake Forest basalt of Wise and Sylvester (2004) (Pliocene and (or)QPvlf Pleistocene) 
Unnamed volcanic and intrusive rocks (Pliocene and (or) Pleistocene) 
Basalt flows, flow breccia and basaltic ash 
QPia - intrusive andesite and latite; QPib - intrusive basalt 
Tahoe City trachyandesite of Wise and Sylvester (2004) (Pliocene)
Pvtcc - cinder cone deposits
Tahoe City basalt of Wise and Sylvester (2004) (Pliocene)
Polaris olivine latite of Birkeland (1961) (Pliocene)
Pvpt - latite tuff and tuff breccia
Alder Hill basalt of Birkeland (1961) (Pliocene)
Pvahcc - cinder cone deposits
Fluvial and lacustrine deposits (Pliocene) 
Unnamed volcanic and intrusive rocks (Pliocene)
Andesite and basaltic andesite flows 
Andesite lahars 
Basalt flows - includes Boca Ridge flows of Latham (1985) 
Dikes and intrusives - Pia - andesite; Pib - basalt 
Unnamed volcanic and intrusive rocks (Miocene) 
Undivided andesitic and dacitic lahars, flows, breccia and volcaniclastic sediments
Andesite and dacite flows 
Basalt flows 
Fluvial deposits 
Intrusive rocks - Mia - andesite, basaltic andesite and latite;
Mib - basalt; Mir - rhyolite 
Glenbrook volcanic center (Miocene) Mvgi - latite intrusions;
Mvgt - vitric-crystal tuff; Mvgf - trachyte flows and vent fill
Upper lahar sequence of Harwood and Fisher (2002) (Miocene) 
Andesitic lahars 
Andesite flows 
Pumiceous tuff 
Rockslide-avalanche deposits 
Lower lahar sequence of Harwood and Fisher (2002) (Miocene) 
Andesitic lahars 
Andesite flows 
Unnamed volcanic and sedimentary rocks 
Rhyolite tuff (Oligocene and Miocene?) 
Conglomerate and breccia (Oligocene and (or) older Tertiary) 
Granitic rocks 
Aplite and pegmatite dikes (Cretaceous) 
Echo Lake granodiorite (Cretaceous) 
Phipps Pass granodiorite (Cretaceous)
Bryan Meadow granodiorite (Cretaceous) 
Lovers Leap granodiorite (Cretaceous) 
Glen Alpine granodiorite (Cretaceous) 
Tyler Lake granodiorite (Cretaceous) 
Wrights Lake granodiorite (Cretaceous) 
Dicks Lake granodiorite (Cretaceous)
Alaskite at Rubicon Point (Cretaceous) 
Rockbound Valley granodiorite (Cretaceous)
Granodiorite of Waterhouse Peak (Cretaceous) 
Quartz diorite of Grass Lake (Cretaceous) 
Granodiorite of Kingsbury Grade (Cretaceous) 
Tonalite West of Waterhouse Peak (Cretaceous) 
Granodiorite of East Peak (Cretaceous) 
Monzogranite of Spooner Summit of Grose (1985) (Cretaceous) 
Granodiorite of Thornburg Canyon (Cretaceous) 
Granodiorite of Charity Valley (Cretaceous)
Diorite of Caples Lake (Cretaceous) 
Granodiorite of Caples Lake (Cretaceous) 
Freel Peak granodiorite (Cretaceous) 
Burnside Lake adamellite of Parker (1961) (Cretaceous) 
Granodiorite of Daggett Pass (Cretaceous) 
Carson Pass tonalite of Parker (1961) (Cretaceous) 
Granodiorite of Faith Valley (Cretaceous) 
Ebbetts Pass granodiorite of Wilshire (1957) (Cretaceous) 
Granodiorite of Kinney Lakes (Cretaceous) 
Basalt dikes (Cretaceous) 
Quartz monzodiorite north of Daggett Pass (Cretaceous?) 
Breccia pipe (Cretaceous?) 
Camper Flat granodiorite (Cretaceous or Jurassic?) 
Desolation Valley granodiorite (Cretaceous or Jurassic?) 
Keiths Dome quartz monzonite (Cretaceous or Jurassic?) 
Unnamed granitic rocks of the Sierra Nevada batholith 
Granite and granodiorite, undivided (Cretaceous) 
Quartz diorite and diorite (Cretaceous)
Diorite and gabbro (Cretaceous) 
Granite (Cretaceous and (or) Jurassic) 
Granodiorite (Cretaceous and (or) Jurassic) 
Diorite and gabbro (Cretaceous and (or) Jurassic) 
Jurassic intrusive rocks: 
Quartz diorite at Azure Lake (Late? and Middle Jurassic) 
Pyramid Peak granite (Jurassic) 
Diorite (Jurassic?)
Diorite and gabbro (Late? and Middle Jurassic)
Microdiorite dikes (Jurassic)
Mafic intrusive breccia (Late? and Middle Jurassic) 
Anorthosite (Late? and Middle Jurassic)
Metamporhic rocks 
Tuttle Lake Formation of Harwood (1992) (Late? and Middle Jurassic) 
Lava flows
Volcanic breccia
Tuffaceous sandstone and conglomerate
Sailor Canyon Formation (Middle and Early Jurassic) 
Metamorphic rocks undivided (Jurassic and (or) Triassic) 
Metasedimentary rocks (Jurassic and (or) Triassic) 
Metavolcanic rocks (Jurassic and (or) Triassic) 
Limestone (Late Triassic?) 
Lake Tahoe Sequence of Harwood (1992) 
Pelite unit (Jurassic?
Ellis Peak Formation (Jurassic)
Blackwood Creek Formation (Jurassic)
Serena Creek Formation (Mississippian? or younger) 

Contact - solid where well or approximately located;
dashed where inferred or gradational.
Fault - solid where well located; dashed where
approximately located; short dash where inferred;
dotted where concealed; queried where continuation or
existence is uncertain. Ball and bar on downthrown side.
Thrust fault - solid where well located; dashed
where approximately located.
Anticlinal fold - arrow indicates plunge direction.
Synclinal fold - arrow indicates plunge direction.
Glacial moraine crest
Dikes - andesite, latite, basalt and mafic dikes; dashed
where approximately located.
Arrows on landslides indicate direction of movement.
Maar at Lake Forest on the Kings Beach Quadrangle.
Strike and dip of stratified rocks.  Number indicates dip angle in degrees when known
Inclined beds
Inclined beds - ball indicates top direction known
Vertical beds
Overturned beds
Strike and dip of metamorphic and igenous foliation and cleavage
Foliation or cleavage
Vertical foliation or cleavage
Cleavage parallel to bedding
Cleavage parallel to bedding - ball indicates top direction known
Vertical joint

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