~S USGS U.S. Department of the Interior

science for a changing world U.S. Geological Survey

Professional Paper 1727

Plate 2 of 4
117°19'
CORRELATION OF MAP UNITS
9 al
sbe2 i r Holocene

A . 5

sc3
», 5 > QUATERNARY 117917"
sbe2
r Pleistocene a
35°54" 8 y¥
. DESCRIPTION OF MAP UNITS

[See plate 1 for map location. Searles Lake Formation is a newly accepted forma-
tion described in the text. Note unit names may change from map to map]

al Alluvium (uppermost Holocene)—Gravel and sand in active channel

coal Older alluvium (upper and middle Holocene)—Medium to coarse
sand, some pebbles, inactive, forms smooth, nearly channel-free
surfaces

Searles Lake Formation (middle Holocene to upper Pleistocene)

Unit C (upper Pleistocene) |

Sand—Lacustrine deposits; tan, very coarse, fairly well sorted;
extends up to 2,280 ft elevation, thickest deposits above 2,200 ft
elevation, forms a veneer at lower elevations; components derived
from Argus Range
Gravel—Alluvial deposits; gray to orange, coarse angular
fragments at lower elevations, mostly rounded near upper elevation
limits
Silt—Lacustrine deposits; grayish-orange, deposited behind bar
composed of subunit sc1c
Sand—Lacustrine deposits; tan, very coarse, well sorted; extends as
high as 2,280 ft elevation. Components derived from Argus Range
Gravel—Lacustrine deposits; mostly as sheets, brownish-orange,
fragments mostly well-rounded pebbles, grade downward and
laterally to crossbedded, very coarse sand; components derived
from Slate Range
Gravel—Lacustrine deposits; mostly as bars, forms dark surfaces;
components derived from Slate Range

Unit BC (upper Pleistocene)

35°36"

Gravel—Alluvial deposits; fragments stained brown or brownish-
orange, angular fragments mostly cobble size
Silt and sand—Alluvial, colluvial, and aeolian (loess?) deposits;
tan, locally contains small pebbles, calcareous soil developed on
surface

Unit B (upper Pleistocene)

Silt—Lacustrine deposits; white, green, or tan, calcareous,
abundant ostracodes; accumulations of nodose tufa at base and top;
bed contains some sand and, in upper part, some gravel
Gravel—Lacustrine deposits; forms surfaces that are dark, mostly
as bars; components derived from Slate Range

Unit AB (upper Pleistocene)

Gravel—Alluvial deposits; pronounced orange stain on top surface
or throughout, angular pebble-sized fragments, thin beds
Sand and gravel—Lacustrine deposits; light- to dark-brown, sand
coarse to very coarse, well sorted, prominent cross-stratification,
spongy lithoid tufa near top and base of unit; components derived
from both Argus Range and Slate Range
Sand and gravel—Alluvial and near-shore lacustrine deposits;
below 1,880 ft mostly fine lacustrine gravel and sand; above 1,880
ft mostly sand and pebbly alluvium; tan; some lacustrine deposits,
1 m of lacustrine bar gravel at base of some outcrops

Unit A (upper Pleistocene)

Sand and gravel—Lacustrine deposits; tan to brown, well sorted,
coarse sand and fine gravel, indurated, sporadic mollusks;
fragments derived from Argus Range
Tufa, undivided (upper Pleistocene)—Lacustrine deposits; tan to
brown lithoid or nodose tufa, composed of aragonite or calcite with
organic impurities, forms towers, mounds, and sheets
Contact—Queried where gradational or poorly exposed 35°35"

HW BEER Bee Bee

—+—+— Crest of lacustrine bar

10> Strike and dip of beds

—~

f——4

CORRELATION OF MAP UNITS

al
oal > Holocene
<
p QUATERNARY
rPleistocene

‘cog

Pleistocene | QUATERNARY
ous Lo] or Pliocene * or TERTIARY

Lx | Miocene? | TERTIARY

DESCRIPTION OF MAP UNITS

[See plate 1 for map location. Searles Lake Formation is a newly accepted
formation described in the text. Note unit names may change from map to map]

al Aluvium (uppermost Holocene)—Gravel and sand, in active channels
oal Older alluvium (upper and middle Holocene)—Medium to coarse
sand, some pebbles and cobbles; inactive; forms smooth, nearly 35°34"

channel-free surfaces
Searles Lake Formation (middle Holocene to upper Pleistocene)

Unit CD (lower Holocene)

Sand and gravel—Alluvial sand and gravel, fragments angular, tan
to gray; inactive, forms smooth, nearly channel free, surfaces
preserve channels; unit is overlain by older alluvium (oal) and is
dissected by alluvium (al)

Unit C (upper Pleistocene)

Silt and sand—Lacustrine deposits; greenish- to light-yellow,

laminated g
Gravel—Lacustrine deposits; medium- to dark-gray, well sorted and rudd
rounded 9 cog?

Unit BC (upper Pleistocene) c

Sand and gravel—Alluvial and colluvial deposits; brown to

orange-brown desert varnish(?) coats many pebble-gravel and

coarse-sand zones; weak soils developed on upper surfaces
Unit B (upper Pleistocene)

Silt and sand—Lacustrine deposits; greenish to tan or orange

Gravel—Lacustrine deposits; dark-gray, well sorted and rounded,
fragments mostly cobble to small boulder sizes
Unit AB (upper Pleistocene)

Gravel—Alluvial and colluvial gravels interbedded with lacustrine
silt, sand, and gravel; alluvial fragments poorly sorted, angular, up
to boulder sizes, tan on fresh surfaces, form dark-orange-brown-
weathered surfaces; lacustrine deposits mostly gravel, well sorted,
tan to gray, form prominent bars at 1,860, 1,940, and 2,120 fi

Unit A (upper Pleistocene)

Sand and silt—Lacustrine deposits; tan, light-yellow to light-green,
locally well bedded
Gravel—Lacustrine deposits; dark-gray, cobble and boulder
fragments are well rounded and sorted, unit includes eroded surfaces
of older gravels on which shorelines of this age have been carved

Tufa, undivided (upper Pleistocene)—Lacustrine deposits; nodose
and lithoid tufa, tan to brown, composed of either aragonite or
calcite

Christmas Canyon Formation (middle Pleistocene)

Gravel and sand—Alluvial gravel, poorly sorted and bedded, largest
fragments are cobble to boulder sizes, vesicular basalt boulders
common west of Randsburg Wash

Older tufa (middle to lower Pleistocene or Pliocene)—Lacustrine 35°33'
deposits; massive, calcite with clastic impurities, gray

QTs Sandstone (lower Pleistocene or Pliocene)—Mostly lacustrine deposits;
gray to tan, coarse sand, moderately indurated and deformed

iltstone and sandstone (lower Miocene?)—Lacustrine deposits; silt

and fine sand tan to light-yellow, coarser deposits darker; some
evaporite minerals; fairly well indurated, intensely folded

Contact—Certain

A:

——+—— Crest of lacustrine bar

io Strike and dip of beds "717
Base fom U.S. Geological Survey, 1:62,500, Geology mapped by G.I. Smith, 1961-1970, 1983-1996
Searles Lake, 1949 Digital database by J.E. Robinson
Polyconic Projection Digital cartography by J.E. Robinson and Richard Koch

Edited by J.L. Zigler

Plate 2B—Randsburg Wash

OMI

Base fom U.S. Geological Survey, Geology mapped by G.I. Smith, 1961-1970, 1

1:62,500, Trona, 1949 1983-1996 i £

Polyconic Projection Digital database by J.E. Robinson ale
Digital cartography by J.E. Robinson and Ze
Richard Koch =
Edited by J.L. Zigler “DECLINATION. 2009

SCALE 1:10 000

Plate 2A—Valley Wells Wash 1” ue 0 yew

500 0 500 1000 1500 2000 2500 3000 3500 FEET
———-—— 1

F 25 0 .5 KILOMETER
—

CONTOUR INTERVAL 40 FEET

NATIONAL GEODETIC VERTICAL DATUM OF 1927

Geologic Maps of Valley Wells Wash and Randsburg Wash

® Printed on recyloed paper

Any use of trade, product, or firm names inthis publication is for gel. Smith, G.1., 2009, Late Cenozoic Geology and Lacustrine History of Searles
ddoscriptive purposes only and does not imply endorsement by the Valley, Inyo and San Bernardino Counties, California: U.S. Geological Survey
US. Government 2009 Professional Paper 1727 [http://pubs.usgs. gov/pp/1727 |