Nbmg Of074

Prepared as part of the STATEMAP component of the National Cooperative Geologic Mapping Program in cooperation with the U.S. Geological Survey

NEVADA BUREAU OF MINES AND GEOLOGY

39o30'0"N

118°37'30"W

118°35'0"W

OPEN FILE REPORT 07-4 PRELIMINARY GEOLOGIC MAP OF THE LAHONTAN MOUNTAINS QUADRANGLE, CHURCHILL COUNTY, NEVADA 118°32'30"W

118o30'0"W

39o30'0"N

Alluvial and aeolian (subaerial) deposits Holocene

Qfy3 Qfy2

Qay2 Qfy

Lacustrine deposits Qfs

Qfe

Qay1

Ql

Qfy1 Qai3

late Pleistocene

QUATERNARY

Qp Qlb

Qsu

Qsm Qsmd Qsm

Qsmb

Qe

Qeg

Qsmt

Qsl

Qslm

middle/early Pleistocene

Qws

QTs

Bedrock units QTb

Miocene to Pliocene

TERTIARY

Ts Teh Trd Trb

39°27'30"N

Qay1

Young alluvium of recently active washes

Qay2

Youngest alluvium of recently active washes

Qp

Ephemeral playa deposits

Qfy

Young fan alluvium, undifferentiated

Qfy1

Young fan alluvium of middle to early Holocene age

Qfy2

Younger fan alluvium of late to middle Holocene age

Qfy3

Youngest fan alluvium of late Holocene age

Qai3

Remnant alluvial fan surfaces

39°27'30"N

Fallon Formation Qfs

Shallow lake sediments of late to middle Holocene age

Qfe

Eolian sand derived from lacustrine deposits of late to middle Holocene age

Ql

Young lake deposits

Qlb

Beach and shoreline deposits

Sehoo Formation Qslm

Lacustrine silt, sand, and mud of the lower and middle Sehoo Fm, undifferentiated

Qsl

Lacustrine silt, sand, and mud and locally beach gravel of the lower Sehoo Fm

Qsm

Lacustrine silt, sand, and mud of the middle Sehoo Fm

Qsmb

Beach and shoreline deposits associated with principal middle Sehoo lacustral cycle

Qsmd

Tufa-bearing beach and shoreline deposits of the middle Sehoo lacustral cycle

Qsmt

Massive dendritic and lithoid tufa associated with the middle Sehoo lacustral cycle

Qsu

Lacustrine silt sand, and mud of the upper Sehoo Fm

Wyemaha Formation Qws

Subaerial sand and alluvial fan gravel deposits separating the Sehoo and Eetza lacustral cycles

Eetza Formation Qe

39°25'0"N

Lacustrine silt, sand, and mud of the Eetza lacustral cycle

Qeg

39°25'0"N

Beach and shoreline deposits of the Eetza lacustral cycle

QTs

Subaerial silt, sand, and gravel deposits

Bunejug Formation QTb

Olivine basalt flows with minor basaltic tuff

Ts

Tertiary sediments, undifferentiated

Teh

Eagles House rhyolite

Trd

Dacite of Rainbow Mountain

Trb

Basalt of Rainbow Mountain with basaltic dikes

Symbology (per FGDC-STD-013-2006)

Contact Solid where certain and location accurate, longdashed where approximate, short-dashed where inferred.

%

25

? ? ? Normal fault, moderately to steeply dipping Solid where certain and location accurate, long-dashed where approximate, short-dashed where inferred, dotted where concealed; queried if identity or existence uncertain. Dip of contact shown locally.

Adjoining 7.5' quadrangle names

1954 Earth rupture Solid where certain and location accurate, long-dashed where approximate, short-dashed where inferred.

Shoreline Thick at 1332m Sehoo highstand, thin at recessional scarps. Hachures point toward water body. Beach ridge

1 2 3 4 5 6 7 8 9

1

2

3

4

5

6

7

8

9

Indian Lakes Stillwater Foxtail Lake Grimes Point Lahontan Mountains Diamond Canyon Carson Lake Bunejug Mountains Fourmile Flat

Strike and dip of bedding

o ¦ ¨ 41

39o22'30"N

118°37'30"W

118°35'0"W

39o22'30"N

118°32'30"W

PRELIMINARY GEOLOGIC MAP OF THE LAHONTAN MOUNTAINS QUADRANGLE, CHURCHILL COUNTY, NEVADA

118o30'0"W

Strike and dip of flow banding or flow foliation in volcanic rocks 33

Inclined

Scale 1:24,000 0

0.5

0

John W. Bell, P. Kyle House, and S. John Caskey 2007

Inclined

0

1000

2000

Field work done in 2006-2007 Supported by the U.S. Geological Survey STATEMAP Program (Agreement No. 06-HQ-AG-0021)

1 kilometer

0.5 3000

1 4000

Vertical

5000

mile feet

CONTOUR INTERVAL 40 FEET Base map: U.S. Geological Survey Grimes Point and Lahontan Mountains 7.5' quadrangles (1985) Projection: Universal Transverse Mercator, Zone 11, North American Datum 1927 (m)

DRAFT Preliminary geologic map Has not undergone office or field review Will be revised before publication Edited by Dick Meeuwig Compilation by John W. Bell, P. Kyle House, and S. John Caskey Cartography and map production in ESRI ArcGIS v9.2 by Jordan Hastings, Elizabeth Crouse, and Matthew Richardson First Edition, July 2008 Printed by Nevada Bureau of Mines and Geology This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and X and Y directions on the same plotter, and paper may change size; therefore, scale and proportions may not be exact on copies of this map.

For sale by: Nevada Bureau of Mines and Geology University of Nevada, Reno / 178 Reno, Nevada 89557-0178 ph. (775) 784-6691, ext. 2 www.nbmg.unr.edu; [email protected]

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