Nbmg Map Of038

39°00'00"

R25E

119°15'00"

R24E

Qai

Qay1

Qai

Qai

br

Qai

Qay1

br

Qai

br

Qay2

Qay1

Qay3 Qay3

Qay1

Qay

Qai

Qf2

Qm1

Qm2

Qx

Qay3

Qao

Qai Qay3

Qe

Qay1

Qai

Qe br

Qay1

br

br

Qay2

br

Qai

Qe

Qai

Qai

Qay1

Qe

Alluvial deposits of intermediate-age, abandoned alluvial fans (late(?) Pleistocene)MComposition ranges from sand to boulders. Surface morphology ranges from moderately to deeply incised. Ridge-and-ravine topography is common. On relict surfaces, soils have moderate to strong Bt horizon and well-developed Bk horizons with Stage 3 carbonate morphology.

Qay2

br

Qay1

Qm2

Qao

Qae

Qf1

br

Qe

br

br

Qao

Qe

Qay1

Qe

Qao

Qao

Qay1

Qe

Qao

Qay

Qf1

br

Qe

Qx

Qay

Qm1

Qa

Qf1

Qay3

Qm2

Qay2

br

Qay2

Qf1

br

Qay1

Qay2

Qe

Qae

br

Qfm

Qe

Qe

Qf1

Qf1

Qfm

Qay2 Qm1 T13N

T13N

Qay1

Qay1 Qay2

Qay2

T12N

Qay2

br

Qx

Qay2

Qm2

Qa

Qf2

Qay2

Qaop

Qay2

Qe

Qay2

br

br

Qe

Stipple pattern indicates areas of significant disturbance due to agricultural, residential, commercial, or industrial development.

Qf2

Qf2

Qf1

Qae

Qf2

Qay1

Qf2

Piedmont

Qay2

Qay2

Qay1 Qm2 Qf2

Qm2

Qe

Qe

br

Qao

Qay1

Qf2

Qay2 Qfm

Qai

Qay1

Qe

Qay1

Qae

Qay2

Qf2 Qm2

Qaop

Qay

Qm2

Qe

Qe

?

?

?

DRAFT Preliminary geologic map. Has not undergone office or field review. May be revised before publication.

Scale 1:24,000 0

0.5

0 0

br Qm2

Qm1

1 kilometer 0.5

1 mile

Qfm Qay

Qf2

Qay

Qaib

Qae

Qm2

Qf1

Qaib

Qm2

Qai

Qf2

Qe

Qaop

Qm2

Qfm

Qls Qaib

br

Qf2

Qm1

Qf1

Qe

Qm1

Qm2

Qf1

br

Qfm Qfm Qay

Qai R24E

R25E

Qm1

Qm2

119°07'30"

Qaib Qaib

1000

2000

3000

4000

5000 feet

First Edition, first printing 2001 Printed by Nevada Bureau of Mines and Geology(1254yerington11-13-01.ai) Edited by Cartography by Robert Chaney The geologic mapping was supported by the U.S. Geological Survey STATEMAP Program (Agreement No. 00-HQ-AG-0048).

CONTOUR INTERVAL 40 FEET Supplemental contour interval 20 feet Base map: U.S. Geological Survey Yerington 7.5' Quadrangle, 1986 Digital Raster Graphic (DRG)

Qf1

Qaop

119°15'00"

Qao Qao p

Qf1

Qaop

38°52'30"

Qaib

Field work done in 2001. Field assistance and preliminary map compilation by James Sutherland.

Qay1

Qay

Qai

Qai

Qae

Qf1

Qf1

Qe Qae

br

Qay2

Qe

Qay

Qx

Qm2

Qay3

Qe Qe

Qm1

Disturbed

Qls

Qf1

Qe

Qaop

Qf2

Qfm

Qf1

Qm1

Qf2

Qa

Qa

Qf2

Qay2

Qai

Qf2

Pleistocene

Qay1

Qay

Qfm Qay

Qai

Qe

Qf1

Eolian

Qay2

Qf2

Qay1

Qai

Qf2

Qfm

Qai Qe

Qm2

QUATERNARY

Qe

Qay2

Qf1

Holocene

Qay1

River

Qay1

Qay2

Qay1

Qaop

Qf1

Qe

br

Normal faultMBall on downthrown side; dashed where inferred or approximately located; dotted where concealed.

Qae

Qay1

Qe

Qe

Qaop

Qfm

Qay2

Qai

Qai

Qe

Lithologic contactMDashed where inferred or approximately located.

Qay2 Qe

Qe

Qay

Qm2

Qe

Qay2

Proffett, J.M., and Dilles, J.H., 1984 Geologic map of the Yerington district, Nevada: Nevada Bureau of Mines and Geology Map 77, 1:24,000. Stewart, J.H., and Dohrenwend, J.C., 1984, Geologic map of the Yerington Quadrangle, Nevada: U.S. Geological Survey OpenFile Report 84-212, 1:62,500.

Meander traceMDiscernible through floodplain cover. Qm1 Qfm

Qe

Qe

References

Qae

Qm2

Qm2

Qf1

Qay1 Qay1

Qf2

Qf2

Qay1

Qay2

Qe

Qe

Qf2

Qay1

Qai

Qay2

Undifferentiated bedrock (Cenozoic to Paleozoic)MMultiple bedrock units juxtaposed in structural arrangements of varying complexity. See Proffett and Dilles (1985) for a detailed map of bedrock units in most of this quadrangle.

br

Qls

Qay2

Qay2

Bedrock

Intermediate-age landslide deposit (late(?) Pleistocene)MChaotic mass of angular basalt boulders and gravel below southern edge of Black Mountain in southwest part of quadrangle (see also Stewart and Dohrenwend, 1984). Forms irregular, hummocky topography in steep terrain. Mixed with and overlapped by deposits of angular, basaltic colluvium. Position in landscape and degree of erosion/incision suggests Pleistocene age.

T12N

Qe

Disturbed areas (modern to historical)MAreas of significant disturbance or burial of surficial deposits by mineral-resource extraction and related activities.

Qx

Older alluvial deposits overlying pediment surfaces (middle(?) Pleistocene)MThin veneers of older alluvium on irregular bedrock pediments. Thickness ranges from 1 to as much as 10 m. Irregular bedrock outcrops are common at surface and widespread in slopes along incised channels. The bedrock-alluvium contact is difficult to define and is an approximation as mapped. This deposit and landform association is most common in the southwest part of the quadrangle. On the east side of the range, it is associated with thin patches of alluvium on the footwall of the range front fault. Soils are poorly exposed and presumably degraded. Locally, chips of laminar, Stage 4 soil carbonate are on the surface. This unit is presumably correlative to Qao, but may include older deposits and landforms. A similar unit was mapped and subdivided further by Stewart and Dohrenwend (1984).

Qx

br

Miscellaneous

Qaop

Qay2 Qay2

Undifferentiated (mixed) alluvial and eolian deposits (Holocene and late Pleistocene)MThis unit indicates areas in the quadrangle where discerning distinct eolian and alluvial deposits is difficult and the eolian mantle predominates. This unit is characteristic of piedmont slopes on the eastern edge of the Walker River floodplain.

Qae

Older, abandoned alluvial fans (middle(?) Pleistocene)MAlluvial deposits of older, abandoned alluvial fans. Often overlain by thick eolian deposits in fanhead and upper fan areas. Medial and distal portions of fan surfaces characterized by ridge-and-ravine topography and deeply incised channels locally. Soil development on most well-preserved surfaces is characterized by strong Stage 3 to Stage 4 carbonate morphology. These deposits form a variably thick (1-10 m) mantle of alluvium and eolian sediments over an irregular bedrock surface in mountain front embayments along the east side of the Singatse Range. However, they are less extensively and conspicuously associated with pediment surfaces than similar deposits in the southwest corner of the quadrangle (unit Qaop).

Qe

Qe

Eolian deposits (Holocene and late Pleistocene(?)) Eolian deposits of fine to medium sand. Extensive planar sand sheets and local, irregular dunes on middle and upper piedmont slopes and thick, irregular hanging dunes in interior niches of the Singatse range. Thickness ranges from 1 m up to 10 m locally.

Qe

Qao

Qay1

br

Eolian Deposits

Bouldery alluvial deposits of intermediate-age, Qaib abandoned alluvial fans (late(?) Pleistocene) Distinctly boulder-rich alluvial fan deposits found only in the southwest portion of the quadrangle. Surface characterized by distinct, low ridges composed of imbricated cobbles and boulders. Often present as a thin veneer (1-2 m) overlying bedrock in upper fan areas.

br Qao

Abandoned, young meander belts of the Walker River (historical and late Holocene) Compositionally and morphologically similar to Qm1. Distribution of unit defined by cross-cutting relation with Qm1 and disconnection from active meander belt. Unit is likely to include abandoned meander belts of various ages. Typically obscured by agricultural development. Meander scars and point bar scrolls discernible in aerial photographs, but many portions of the deposit surface are planar due to anthropogenic modification and slight burial by overbank sedimentation. Portions of this unit may be related to channel realignment efforts in the historical period.

Qm2

Qai

br

Qf1

Qay

Qay

br

Qao

br

br

Qe

Qai

Qay2

Qay

Qay1 Qay2

Alluvium of younger abandoned alluvial fan surfaces (middle Holocene to late Pleistocene(?)) Composition ranges from fine sand to small boulders. Surface morphology varies from extremely subdued bar-and-swale to planar form. Soil profiles characterized by well developed Av horizons (5-10 cm), distinct reddened Bw horizons, and thin Bk horizons with Stage 1-2 carbonate morphology.

Qay1

br

Qai

Qfm

Qai

Qay1

Qai

Active meander belts of the Walker River (modern and late Holocene)MComposition ranges from lateral accretion deposits of sand and gravel to vertical accretion deposits of mud and sand. Surface topography is irregular and includes abandoned, overprinted sinuous channel courses and relict planar floodplain surface remnants.

Qm1

Qay3

Qf2

Qai

Qe

br

Qm2

Qx

Qay1

Qai

Qay2

Qa

Qai

Qay2

Qai

br

Qai

Qf2

Qf1

Qai Qay1

br

Qay

Qao Qe

Qe

Qay1

br

Qao

Alluvium of intermittently active and recently abandoned channels and alluvial fans (late and middle Holocene)MComposition ranges from fine sand to medium boulders. Surface morphology characterized by subdued bar-and-channel to bar-and-swale texture. Minor varnish present on susceptible clasts, but minor to no significant soil development.

Qay2

br

Infrequently active and abandoned floodplain of the Walker River (late and middle Holocene)MFinegrained alluvial deposits similar to Qf1, but typically overlain by eolian silt. Composition ranges from organic-rich mud to sand and gravel. Often overlain by a veneer of eolian silt. Only exposed in isolated areas not subject to agricultural development. Surface topography is planar.

Qf2

Qay2

Qm1

Qay

Qao

Qe

Qao

Qm2

Qay

Most frequently active floodplain of the Walker River (modern and late Holocene)MFine-grained alluvial deposits. Composition ranges from vertically accreted organic-rich mud to sand. Largely obscured by extensive agricultural development. Surface topography is planar.

Qf1

Alluvium of active channels and alluvial fans (modern and late Holocene)MDeposits ranging in composition from fine sand to medium boulders associated with ephemeral stream flow and debris flows. Surface morphology characterized by pristine channels, gravel bars, and bouldery debris flow lobes in confined channels and on broad alluvial fan surfaces. This unit is predominantly associated with historical debris flows on the Singatse piedmont below McConnell Canyon, Western Nevada Canyon, and Sand Canyon. This unit has no significant soil development.

Qay1

Qfm br

Qay1

Qf2

Qf1

Qay1

Qe

Undifferentiated young piedmont alluvium (Holocene and late Pleistocene(?))MIncludes broad areas containing various-age deposits of sand, gravel, and boulders. Extent of individual deposits of distinct age and surface properties are too small or irregular to map meaningfully.

Qf1

Qay

Qao Qay1

Undifferentiated floodplain and meander belt deposits of the Walker River (modern and Holocene)MFine-grained alluvium ranging from vertical accretion deposits of mud and sand to lateral accretion deposits of sand and gravel. Organic-rich muds are common at the surface. Surface topography is generally planar. Portions are covered by thin (up to 10 cm) veneer of eolian silt.

Qfm

Qay

Qfm

Qay3

Alluvium of the Walker River and its Main Branches

Undifferentiated piedmont surficial deposits Qa (Holocene and Pleistocene)MAlluvium, colluvium, and eolian deposits variously composed of silt, sand, and gravel.

Qm2

Qay1 Qay 3

br

Piedmont Alluvium

br

Qay3

Qay

Qfm

119°07'30"

39°00'00"

OPEN-FILE REPORT 03-8MPRELIMINARY QUATERNARY GEOLOGIC MAP OF THE YERINGTON QUADRANGLE, LYON COUNTY, NEVADA

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

Qm1 Qf1

38°52'30"

Nevada Bureau of Mines and Geology University of Nevada, Mail Stop 178 Reno, Nevada 89557-0088 (775) 784-6691, ext. 2 www.nbmg.unr.edu; [email protected]

PRELIMINARY QUATERNARY GEOLOGIC MAP OF THE YERINGTON QUADRANGLE, LYON COUNTY, NEVADA P. Kyle House 2001