Facies Analysis of Tertiary Basin-Filling Rocks of the Death Valley 

Regional Ground-Water System and Surrounding Areas, Nevada and 

California 

By Donald S. Sweetkind, Christopher J. Fridrich, and Emily Taylor 

Open-File Report 01-400 

Prepared in cooperation with 

OFFICE OF ENVIRONMENTAL RESTORATION AND WASTE MANAGEMENT, 

U.S. DEPARTMENT OF ENERGY 

NATIONAL NUCLEAR SECURITY ADMINISTRATION 

NEVADA OPERATIONS OFFICE, under 

Interagency Agreement DE-AI08-96NV11967 

2001 

This report is preliminary and has not been reviewed for conformity with 

U.S. Geological Survey editorial standards or with the North American 

Stratigraphic Code. Any use of trade, product, or firm names is for 

descriptive purposes only and does not imply endorsement by the U.S. 

Government. 

U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY 

1 
Contents 

Abstract......................................................................................................................................... 4 

Introduction.................................................................................................................................... 5 

Cenozoic Stratigraphy of the Death Valley Region .......................................................................... 7 

Early Extensional Sequence....................................................................................................... 9 

Synextensional Sequence........................................................................................................ 13 

Late extensional/post-extensional sequence ............................................................................ 18 

Stratigraphic Setting of Tertiary Basin-Filling Deposits................................................................. 18 

Methods of Study......................................................................................................................... 21 

Outcrop Data .......................................................................................................................... 21 

Subsurface Data ..................................................................................................................... 21 

Tertiary Thickness Modeled from Gravity Data ....................................................................... 32 

Regional Facies Trends................................................................................................................. 34 

Thickness ............................................................................................................................... 34 

Compositional Trends.............................................................................................................. 34 

Amargosa Desert Borehole Data................................................................................................... 41 

Summary of Material Properties ................................................................................................... 47 

References cited........................................................................................................................... 50 

Figures 

1. Location map and place names, Death Valley region ............................................................... 6 

2. Diagrammatic examples of possible stratigraphic position of undifferentiated 

Tertiary volcanic and sedimentary rocks ............................................................................. 20 

3. Location map of outcrops and boreholes used in this study ................................................... 22 

4. Thickness of Cenozoic basin fill based on gravity model ........................................................ 33 

2 
 5. Thickness of undifferentiated Tertiary basin fill based on measurements in 

outcrop and in boreholes...................................................................................................... 35 

6. Thickness of Tertiary sedimentary rocks based on measurements at outcrops 

and in boreholes .................................................................................................................. 36 

7. Thickness of Tertiary volcanic rocks outside the southwestern Nevada 

volcanic field ....................................................................................................................... 37 

8. Thickness of Tertiary limestones based on measurements at outcrops and in 

boreholes............................................................................................................................. 39 

9. Relative proportion of sedimentary rocks in the Tertiary section and grain-size 

characteristics..................................................................................................................... 40 

10. Relative proportion of volcanic rocks in the Tertiary section and rock type .......................... 42 

11. Location map of boreholes and stratigraphic cross sections in the vicinity of 

the Amargosa Desert........................................................................................................... 44 

12. Stratigraphic cross section A-A’........................................................................................... 45 

13. Stratigraphic cross section B-B’........................................................................................... 46 

14. Map showing location of zones that may define major regional differences in 

material properties .............................................................................................................. 48 

Tables 

1. Location of outcrop data used for facies analysis..............................................................23 

2. Thickness data for lithologic types from measured sections and 

outcrop descriptions.........................................................................................................24

3. Location of borehole data used for facies analysis.............................................................26 

4. Thickness data for lithologic types from boreholes............................................................29 

3 
Facies Analysis of Tertiary Basin-Filling Rocks of the Death Valley Regional 

Ground-Water System and Surrounding Areas, Nevada and California 

By Donald S. Sweetkind, Christopher J. Fridrich, and Emily Taylor 

Abstract 

Existing hydrologic models of the Death Valley region typically have defined the 

Cenozoic basins as those areas that are covered by recent surficial deposits, and have 

treated the basin-fill deposits that are concealed under alluvium as a single unit with 

uniform hydrologic properties throughout the region, and with depth. Although this latter 

generalization was known to be flawed, it evidently was made because available geologic 

syntheses did not provide the basis for a more detailed characterization. As an initial 

attempt to address this problem, this report presents a compilation and synthesis of 

existing and new surface and subsurface data on the lithologic variations between and 

within the Cenozoic basin fills of this region. The most permeable lithologies in the 

Cenozoic basin fills are freshwater limestones, unaltered densely welded tuffs, and littleconsolidated coarse alluvium. The least permeable lithologies are playa claystones, 

altered nonwelded tuffs, and tuffaceous and clay-matrix sediments of several types. In all 

but the youngest of the basin fills, permeability probably decreases strongly with depth 

owing to a typically increasing abundance of volcanic ash or clay in the matrices of the 

clastic sediments with increasing age (and therefore with increasing depth in general), 

and to increasing consolidation and alteration (both hydrothermal and diagenetic) with 

increasing depth and age. This report concludes with a categorization of the Cenozoic 

basins of the Death Valley region according to the predominant lithologies in the 

different basin fills and presents qualitative constraints on the hydrologic properties of 

these major lithologic categories. 

4 
Introduction 

Cenozoic basin-fills of the Death Valley region (fig. 1) range from late Eocene to 

Quaternary in age, from coarse to fine in grain size, from fresh to strongly altered, and 

from unconsolidated to well consolidated. They include a broad range of both volcanic 

and sedimentary lithologies including lavas, welded and nonwelded tuffs, and alluvial, 

fluvial, colluvial, eolian, paludal, and lacustrine sediments. The presence of excellent 

aquifers within parts of these basin fills has been demonstrated by long-term well-water 

production (Dudley and Larson, 1976; Harrill, 1986), whereas the presence of spring 

discharge sites in other areas has been related to structural juxtaposition of confining 

units within some basin fills against more permeable rocks (Winograd and Thordarson, 

1975; Hunt and others, 1966; Dudley and Larson, 1976). Despite their great lithologic 

diversity and proven large variation in hydrologic behavior, those parts of the Cenozoic 

basin-filling sequences of the Death Valley region that are covered by recent surficial 

deposits have commonly been modeled as a unit with uniform hydrologic properties, both 

throughout the region and with depth (IT Corp., 1996; D'Agnese and others, 1997). 

Much of the mystery surrounding the Cenozoic basin fills of the Death Valley region 

reflects the fact that the basins typically have been defined in hydrologic models as the 

areas of present-day cover by unconsolidated surficial deposits. These recent surficial 

deposits are also part of the Cenozoic basin fills, but in most of the region are too thin to 

extend below the water table. Lateral lithologic variations in these largely post-tectonic 

surficial deposits typically bear little or no relationship to those in the older, dominantly 

synextensional and early extensional basin-fill deposits at the depth of the water table and 

below. Exposures of consolidated Cenozoic strata are treated in most hydrologic models 

as a separate hydrologic unit (or units) from adjacent, concealed basin-fill strata. 

However, most outcrops of consolidated Tertiary strata that are exposed adjacent to 

alluvial cover are within the original area of the basins, most of which formed in the 

Miocene. In most cases, these strata project down under the adjacent alluvium and are 

the lateral equivalents to strata concealed under the recent alluvium. These exposures of 

basin fill show that strong lateral changes in lithology, thickness, and structure exist 

5 
38o00' 

30' 

ESMERALDA 

COUNTY 

NYE 

COUNTY 

LINCOLN 

COUNTY 

CLARK 

COUNTY 

INYO 

COUNTY 

SAN BERNARDINO 

COUNTY 

KERN

COUNTY NEVADA CALIFORNIA 

MONO 

COUNTY 

TEST SITE 

NEVADA 

AD 

FF 

LVV 

PV 

YF 

3 

4 6 

8 9 

10 

12 11

13 

14 

18 19

1 

2 

4 

15 5 7 16 

17 

20 21 22 

23 

24 25 

26 

27 

AD 

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AF 

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DV 

NEVADA 

CALIFORNIA 

INDEX MAP 

117o00' 30' 116o00' 115o 118 30' 00' o00' 30' 

38o00' 

30' 

EXPLANATION 

Line of section 

State boundar y 

County boundar 

Nevada T est Site boundary Area depicted on figures 3-10 Area depicted ofigure 11 

AD = Amargosa Deser t
AF = Amargosa F arms area
DV = Death V alley


FF = F renchman Flat


LVV = L as Vegas Valley


PV = P ahrump Valley
YF = Y ucca Flat


1 = Sar cobatus Flat 

2 = Oasis V alley basin 

3 = Bullfrog Hills 

4 = Bar e Mountain 

5 = Crater Flat 

6 = Y ucca Mountain 

7 = Jackass Flat 8 = Rock V alley 9 = Hampel W ash 

10 = Indian Springs 

11 = Ash Meadows 12 = Bat Mountain 

13 = F uneral Mountains 

14 = F urnace Cr eek Wash


37o00' 

30' 

37o00' 30' 

36o00' 

30' 

35o00' 

36o00' 

30' 

35o00' 

118o00' 30' 117o00' 30' 116o00' 30' 115o00' 

0 25 50 75 KIL OMETERS


Figure 1. Location map and place names, Death Valley region, Nevada and California 

6 
within these deposits. Under the areas of alluvial cover, these changes are concealed, but 

much can be surmised by interpolating and extrapolating from adjacent exposures, in 

combination with borehole and geophysical data. 

This report presents a facies analysis of Tertiary basin-filling deposits for the Death 

Valley region, exclusive of the named volcanic units in the vicinity of the southwestern 

Nevada volcanic field. The purpose of this report is to assemble the available 

information on lithologic variations within the Cenozoic basin-filling sequences 

throughout the Death Valley region, based on surface mapping data, drill-hole data, and 

geophysical constraints. These data are then applied to development of a generalized 

characterization of the lithologic variability of the basin fills, along with available 

qualitative information about the relative hydrologic properties of the different 

lithologies. 

Cenozoic Stratigraphy of the Death Valley Region 

This lithologic study addresses primarily the southern part of the Death Valley 

groundwater flow system of the southwest Great Basin, Nevada and California (Bedinger 

and others, 1989). In the Cenozoic, this region has undergone a complex history of 

transtensional deformation, which has ultimately created a tectonic landscape that is a 

mosaic of alternating, narrow basins and ranges (basin-range topography). As the 

tectonic basins of this region formed and evolved, they were filled by a locally thick 

sequence of terrestrial sediments and volcanic rocks, which provide a record of the 

Cenozoic environmental history of this region. This history shows three major types of 

changes in this region over the last 40 m.y., each of which has had a major impact on the 

lithologies in the basin-fill sequences (Fridrich and others, 2000): 

• A progressive change from the initially humid conditions of the Late Eocene, 

to the very arid conditions of today. This climatic change is reflected in a 

change from a dominance of fluvial cobble conglomerates and freshwater 

limestones in the oldest basin-fill sequences to a dominance of alluvial fan 

breccias and playa claystones in the youngest deposits. In addition, the early 

7 
humid conditions fostered the production of clay as a product of weathering, a 

process that has diminished strongly with time. 

• Progressive tectonic fragmentation of the region. The earliest Cenozoic 

tectonism apparently created very broad and shallow basins. Basin-range 

topography, as we know it today, first developed in the Death Valley region 

from ~14-to-~12 Ma, it evolved through three successive tectonic episodes, and 

it is still actively evolving in the southwesternmost part of the Death Valley 

region, and to the west. The tectonic evolution of this region is reflected in 

changes in sedimentation patterns, from an earlier pattern dominated by 

regional-scale fluvial transport to a later pattern dominated by sedimentary 

transport and deposition largely confined within relatively small intermontane 

basins with local sediment sources. 

• Volcanic input to the basins as a result of the strong pulse of volcanism in mid 

and late Miocene time, primarily from the southwestern Nevada volcanic field 

and to a lesser extent from the central Death Valley volcanic field. From ~40 to 

15 Ma, the Death Valley region had no local volcanism. A variety of volcanic 

fields were the source for distal tuffs that reached the region in this initial 

prevolcanic interval. Most of these volcanic source areas were in central and 

southern Nevada and together they defined a slowly southward-migrating 

pattern of volcanism. The migrating pattern of volcanism eventually moved 

into the Death Valley region at ~15 Ma, peaked with very high eruption rates 

between 13.5 and 11 Ma, and then declined with time as the focus of volcanism 

migrated generally westward, largely moving out of the region at ~6 Ma. This 

volcanic history is reflected in changing input of both primary volcanic units 

and of volcaniclastic detritus into basin fills throughout this history. Moreover, 

the volcanism and related tectonism provided the heat for local hydrothermal 

activity, which has greatly reduced the permeability of some basin-fill deposits, 

especially of nonwelded tuffs and ashy sediments. 

Tertiary strata of the Death Valley region have been subdivided into seven 

unconformity-bounded sequences (see fig. 8; Snow and Lux, 1999; Fridrich and others, 

8 
2000). These seven sequences can, in turn, be generalized into three sequences according 

to their relation to the tectonic evolution of the region: (1) an early extensional sequence 

that predates the formation of basin-range topography, (2) a synextensional sequence that 

corresponds to the major period of formation of basin-range topography in this region, 

and (3) a 6-Ma-to-present late extensional to post-extensional sequence. 

The base of the early extensional sequence, which is the basal Tertiary contact, 

varies in age from ~40 to ~25 Ma over different parts of the region. This variation 

appears largely to reflect progressive burial of topography, as discussed below. In 

general the basal Tertiary contact youngs to the west and south within the Death Valley 

region. The contact between the early extensional and synextensional sequences varies 

from ~14 to ~12 Ma in different locales, reflecting local variations in the onset of basinrange tectonism, or the change in sedimentary depositional environments that occurred as 

a consequence of basin-range tectonism. The basal synextensional contact generally 

youngs to the northwest. The contact between the synextensional and the late extensional 

sequences varies from ~10 Ma in the northeasternmost part of the Death Valley region to 

~6 Ma in Death Valley and west of it. Above this contact the strata are late extensional 

from eastern margin of Death Valley westward, and they are post-tectonic to the east of 

Death Valley. The early extensional sequence was prevolcanic up to ~15 Ma, when 

andesite-rhyolite volcanism gradually migrated into the region from the north and east. 

The synextensional sequence coincided with the dominant period of volcanism in the 

region, which was bimodal in character. The late- to post-extensional sequence 

corresponds to a period of waning, largely basaltic volcanism in the Death Valley region. 

Early Extensional Sequence 

Sedimentary strata deposited before the creation of basin-range topography are 

widely distributed throughout the Death Valley region. The major unifying 

characteristics of these early extensional deposits are that: (1) lateral changes in lithology 

in these strata are mostly very gradual throughout the region, (2) abrupt lateral thickness 

changes in the lowermost (~40 to 27 Ma) part of this sequence apparently reflect burial of 

moderately high-relief topography at the basal Tertiary surface, some of which evidently 

was tectonic in origin, and (3) in the few cases where abrupt lateral facies and thickness 

9 
changes are found in the middle and upper (27 to ~14 Ma) part of this sequence, they 

correspond spatially to a small number of long-abandoned structures that are locally 

exposed within the modern-day ranges, rather than to topographically expressed 

(modern-day) basin-range boundaries. 

Lithologically, the early extensional sequence can be divided into three major 

packages, as a generalization. The oldest of these packages largely ranges in age from 

~40 to ~25 Ma and consists dominantly of conglomerates and lesser basal breccias, both 

of cobble-to-boulder-size, mostly in clay-rich matrices. The next package covers the age 

range from ~25 to ~19 Ma and consists mostly of interbedded fluvial sandstones, 

freshwater limestones and marls, and lesser playa claystones and pebble conglomerates. 

Together, these two oldest lithologic packages have been named the Titus Canyon 

Formation in the Grapevine Mountains (Reynolds, 1974), in the northern Funeral 

Mountains (Wright and Troxel, 1993), and in an area immediately west of the Nevada 

Test Site (Fridrich, Minor, Ryder, and others, 1999). They have also been called the 

Ubehebe Formation in the Cottonwood Mountains (Snow and Lux, 1999), the 

conglomerate and limestone members of the Amargosa Valley Formation in the southeast 

Funeral Mountains (Cemen and others, 1999), and the brown gravel unit of the rocks of 

Joshua Hollow on the northeast side of Bare Mountain (Monsen and others, 1992). In the 

Rock Valley area, the equivalent rocks have been called the rocks of Winapi Wash (J. 

Yount, USGS, oral comm., 1992). Earlier, they were mapped as the Horse Springs 

Formation (Hinrichs, 1968), a lithologically similar, but younger (20-12 Ma) unit 

exposed in the area east of Las Vegas (Bohannon, 1984). On most other maps of the 

region, the strata of these oldest two lithologic packages have been lumped with other 

strata as older Tertiary sediments. 

Strata that range in age from ~19 to ~17 Ma are apparently absent throughout the 

Death Valley region, owing to nondeposition or erosion (Fridrich and others, 2000). The 

uppermost of the three sections of the early extensional sequence, above this missing 

section, exhibits greater lithologic variability than all of the older Cenozoic strata. This 

uppermost sequence is ~16 Ma at the base and, as discussed above, has a top that ranges 

in age from ~14 to ~12 Ma. Volcanic rocks within this uppermost early extensional 

sequence consist of andesitic agglomerates and lavas of the central Death Valley volcanic 

10 
field in the southern part of the region and rhyolitic tuffs of the southwestern Nevada 

volcanic field in the northern part of the region. Both of these volcanic sections were 

deposited on a basal (~16 to ~14 Ma) section of sediments, mostly arkosic fluvial 

sandstones (mostly redbeds) in the south and fine-grained tuffaceous sediments with 

locally thick interbedded conglomerates in the north. Moreover, both volcanic sections 

interfinger laterally with arkosic red sandstones that constitute the majority of this section 

in the central part of the region. Volcanic units of the southwestern Nevada volcanic 

field are in general not considered in this report. Only in those areas where tuffs of 

probable affinity to the southwestern Nevada volcanic field are intercalated with coeval 

Tertiary sediments and have not been explicitly identified are they included as part of the 

undifferentiated Tertiary basin-filling rocks. 

This uppermost of the three early extensional sections includes the unnamed redbed 

sections intermittently exposed on either side of the Beatty Junction cutoff road from ~2 

to ~9 km south-southeast of Hell's Gate, at the northwest limit of the Funeral Mountains 

(Wright and Troxel, 1993). It also includes the Panuga Formation of the Cottonwood 

Mountains (Snow and Lux, 1999). In the southeastern Funeral Mountains, it is the upper 

part of the Amargosa Valley Formation. In the Kingston Range, the equivalent section is 

the lower part of the Resting Spring Formation, which is composed predominantly of 

sandstone, limestone, and andesite (Fowler and Calzia, 1999; Friedmann, 1999). In the 

southwestern Nevada volcanic field, this section includes a basal part, which has variably 

been called the Tunnel Formation (in the northern part of the volcanic field, where it 

consists dominantly of bedded tuffs) or the rocks of Pavits Spring (in the southern part of 

the volcanic field, where it consists dominantly of tuffaceous sandstones), among other 

names, and an upper (~14-to-~12-Ma) part, which consists of volcanic formations 

including the Lithic Ridge Tuff and associated units, the tuffs and lavas of the Crater Flat 

Group, and the Wahmonie Formation (Sawyer and others, 1994). 

Hydrologically, the early extensional sequence of the Death Valley region shows a 

range of behaviors. The coarse clastic sediments with clay-rich matrices that constitute 

the majority of the lowermost part of this sequence are predominantly confining units. 

The best evidence for this is the common localization of springs at contacts between Late 

Proterozoic quartzites and these clay-matrix sediments, especially where the quartzites 

11 
are exposed uphill from the Tertiary sequence. These quartzites are generally 

impermeable except where they are locally fractured; they have been classified as part of 

the lower clastic aquitard of the Death Valley region (Winograd and Thordarson, 1972). 

The setting of these hillside springs suggests that the clay-matrix sediments of the lower 

part of the early extensional sequence are even less permeable. Parts of the volcanic 

sections of the uppermost (16-to-~12-Ma) part of the early extensional sequence are 

known to be aquifers, especially the densely welded tuffs. For example, the tuffs of the 

Crater Flat Group, which have been penetrated by numerous drill holes into Yucca 

Mountain and Crater Flat, have been shown to be good water producers in many of these 

wells (Waddell and others, 1984; Luckey and others, 1996). The other strata of the early 

extensional group largely have unproven hydrologic characteristics, but probably cover a 

broad range of properties. Where these sediments are strongly tuffaceous, they typically 

also are quite altered and probably are impermeable. The arkosic sandstones in this 

sequence probably are only marginal aquifers, because they typically contain abundant 

tuffaceous material that is strongly diagenetically altered. Limestones, as a rock type, 

should be a good aquifer, but existing data suggest that the limestones in this sequence 

are very discontinuous, which would strongly limit their importance as aquifers, even if 

they are very permeable. 

The hydrologic behavior of the early extensional sequence also depends upon the 

structural setting in addition to the lithologic factors discussed above. Deposition of this 

sequence predated most of the strong transtensional deformation that has occurred in the 

Death Valley region in the Cenozoic, so these rocks are tectonically disrupted in much of 

the region. This probably has resulted in structural dismemberment of the aquifers in this 

sequence in many areas. However, the confining units in this sequence are also 

dismembered in many areas and are strongly faulted in most of the region; hence these 

confining units, at a minimum, are probably rather leaky in most areas. At Yucca 

Mountain, it is clear from the difference in head between the deep Paleozoic carbonate 

aquifer and the welded tuff aquifer, in well USW p#1, that the impermeable strata in the 

lower part of the early extensional sequence, which intervene between these two aquifers, 

act as an effective confining unit. Thermal and carbon-isotopic data on groundwater 

12 
under Yucca Mountain also show, however, that this confining unit leaks along the major 

faults cutting the mountain (Fridrich and others, 1994). 

In summary, the lower and middle part of the early extensional sequence is typically 

a leaky confining unit, and the upper part is mixed in properties as a function of locale. 

In some areas it is a leaky confining unit like the underlying rocks and elsewhere it is a 

moderately permeable aquifer like most of the overlying units. 

Synextensional Sequence 

In the early extensional sequence, lateral changes in stratigraphic thicknesses and 

lithologic characteristics are very gradual in all directions, in general. In particular, there 

are no appreciable changes across the crests or range-fronts of present-day mountain 

ranges. Locally, the uppermost (~14-to-~12-Ma) part of the ~40-to~12-Ma strata of the 

region includes some tectonic sediments that are related to the initial development of a 

small number of the most major basin-range faults that were active primarily after 12 Ma. 

These earliest group of sediments that are synextensional (relative to the major basinrange-forming tectonic episode) consist primarily of coarse alluvium. At ~12 Ma, the 

shift to predominantly local provenance of the clastic sediments, which had from ~14 to 

~12 Ma been confined to a very localized range, was abruptly extended over the whole 

central and eastern part of the region, reflecting the initial uplift of the modern-day 

mountain ranges, excepting those west of the Death Valley physiographic feature. This 

major basin-range-forming tectonic episode, which began locally at ~14 and became 

regionally extensive at ~12 Ma, continued until about 10 Ma in the northeasternmost part 

of the Death Valley region and to ~6 Ma in the vicinity of the Northern Death 

Valley/Furnace Creek fault. 

The synextensional part of the fill of each of the region's basins is essentially a 

separate formation in each basin. Each of these synextensional basin fills has 

considerable individuality in its thicknesses, lithologies, provenance of clasts, and many 

other features. Moreover, lateral variations in these features are found within each of 

these basin fills that (1) commonly bear a relationship to the northwestward migration of 

the focus of tectonism during the synextensional episode, and (2) commonly exceed the 

variability of the early extensional sequence across the entire region. Moreover, the 

13 
diversity of lithologies in the synextensional strata exceeds that of any of the younger or 

older basin-fill deposits because: (1) the climate during the synextensional episode was 

transitional between the relatively humid before and the relatively arid conditions after 

this time period, resulting in the interlayering of sedimentary rocks deposited in varying 

climatic conditions, and (2) volcanic activity peaked in the synextensional episode, 

resulting in a greater abundance and diversity of volcanic rocks than that found in both 

the younger and older deposits. Because of the very high rate of felsic pyroclastic 

volcanic activity, early (~14-to-~10-Ma) synextensional alluvial deposits of this age 

range typically have matrices that contain significantly more tuffaceous material than do 

any younger or older alluvium of the region. 

As variable as the lithologies are in the synextensional sequence, and as much as 

they vary in character between the different basins of the region, there are certain 

generalizations that can be made about the characteristics of these deposits, as a function 

of geographic position: 

(1) In the vicinity of the southwestern Nevada volcanic field, the major lithologies in 

the synextensional sequence consist of moderately to densely welded tuffs, 

alluvial and landslide breccias, as well as some nonwelded tuffs and lavas (Byers 

and others, 1976; Sawyer and others, 1994). The majority of these deposits are at 

least moderately permeable, except in the area immediately in and around the 

central caldera complex of the volcanic field, where hydrothermal alteration has 

destroyed much of the original permeability (Winograd and Thordarson, 1975; 

Blankennagel and Weir, 1973; Laczniak and others, 1996). Moreover, the 

horizons within these strata that are relatively impermeable are sufficiently faulted 

in most cases that they probably are not effective confining units. The 

approximate areal extent of volcanic rocks derived from the southwestern Nevada 

volcanic field is defined to the west by outcrops in the Funeral and Grapevine 

Mountains, to the south and southeast by borehole intercepts along U.S. Highway 

95 south of Yucca Mountain and in northwestern Frenchman Flat, and to the east 

by depositional pinchouts near the Nye County-Lincoln County line. The area in 

which this characterization applies includes the synextensional sections found in 

the following alluvial basins: Yucca Flat, Frenchman Flat, Jackass Flats, Crater 

14 
Flat, Oasis Valley basin, and Sarcobatus Flat (fig.1). In all of these basins, these 

synextensional deposits overlie early extensional strata that are leaky confining 

units. The deep carbonate aquifer is known or presumed to underlie Yucca Flat, 

Frenchman Flat, and at least parts of the Crater Flat and Jackass Flats basins, but 

is probably absent under the majority of the Sarcobatus Flat basin. In the vicinity 

of the southwestern Nevada volcanic field, the synextensional section consists of 

the tuffs and lesser lavas of the Paintbrush, Timber Mountain and Thirsty Canyon 

Groups, along with many lesser volcanic units and interbedded, largely unnamed 

sediments. 

(2) In the area of the central Death Valley rhombochasm (Wright and others, 1991), 

which extends from the east flank of the Panamint Mountains eastward to the 

Resting Spring Range and from the southwest flank of the Funeral Mountains 

southward to southern Death Valley fault zone, synextensional basin fills are 

largely sedimentary at the base - including conglomeratic sandstones and breccias 

- but otherwise consist primarily of bimodal (dacite-basalt) volcanic rocks and 

tuffaceous sediments (McAllister, 1970; 1973; 1974; Cemen and others, 1985; 

Wright and others, 1991; Greene, 1997). Throughout the majority of this area, 

these rocks are hydrothermally altered to the point where the original permeability 

has been largely destroyed, except perhaps in some of the coarsest sediments, 

locally found near the base of synextensional sections and near the margins of the 

basin. Significant permeability probably has survived in these deposits only in 

very limited locales. The only deposits recognized as significant aquifers within 

this synextensional basin-fill sequence are breccias found along the western flank 

of the Resting Spring Range (Cemen, 1983) that are presumed to project 

westward under the adjacent part of the Amargosa River Valley. Some permeable 

breccias may also be present immediately adjacent to the southwestern flank of 

the Funeral Mountains. Otherwise, the synextensional basin fill deposits of the 

central Death Valley rhombochasm probably are fairly impermeable. The early 

extensional sequence is structurally omitted within most of the Death Valley 

rhombochasm (Wright and others, 1999); synextensional deposits are structurally 

complex and have been included as part of the Amargosa Chaos in the 

15 
southwestern part of the basin (Wright and Troxel, 1984; Topping, 1993). In the 

rest of the basin, the major named parts of the synextensional basin fill include the 

Artist Drive Formation and the coeval Shoshone volcanics as the major units 

(Wright and others, 1991). Paleozoic carbonates probably are present beneath the 

easternmost part of this basin, but are likely to be tectonically thinned and 

discontinuous throughout most of the central Death Valley rhombochasm. 

(3) In the area of the China Ranch basin, Dumont Hills, and around the perimeter of 

the Kingston Range, synextensional Cenozoic deposits consist largely of very 

coarse alluvium and rock-avalanche breccias, which are probably quite 

permeable, and lesser amounts of impermeable playa claystones (Fowler and 

Calzia, 1999; Prave and McMackin, 1999; Friedmann, 1999). The playa 

claystones are present in restricted areas where they typically are completely 

surrounded by alluvium and breccias; hence, it is improbable that they form 

effective confining units because groundwater may flow around these areas of 

impermeable sediments. The limited exposures of synextensional sediments in 

the Pahrump Valley are of sediments similar to those in the China RanchKingston Range area. The synextensional deposits in this area are largely 

unnamed but include the China Ranch beds and the fill of the Shadow Valley 

basin on the south side of the Kingston Range (Prave and McMackin, 1999; 

Friedmann, 1999). 

(4) The Amargosa Desert is the most difficult basin to characterize hydrogeologically 

within the southern Death Valley ground-water system, partly because this huge 

area of alluvial cover is a composite of several structural basins. Additionally, 

Cenozoic strata exposed on different sides of this basin differ strongly in their 

lithologies, suggesting the presence of pronounced lateral facies changes. 

Sediments having the characteristics described in all of the above three areas are 

found in different parts of the Amargosa Desert basin. The synextensional 

sequence (along with the uppermost part of the underlying early extensional 

sequence) includes a large thickness of permeable densely welded tuffs in the 

three areas that border the western arm of the Amargosa Desert, namely, the 

Crater Flat basin (Fridrich, 1999; Fridrich, Whitney, and others, 1999), the 

16 
Bullfrog Hills (Maldonado, 1990; Fridrich, Minor, and Mankinen, 1999), and the 

hills along the northern flank of the Funeral Mountains, just south of the Bullfrog 

Hills (Wright and Troxel, 1993). Aeromagnetic data indicate, however, that 

equivalent volcanic rocks are present only in a spotty fashion under the alluvium 

that intervenes between the exposures in these three areas (Grauch and others, 

1999; Blakely and others, 2000). The drilling evidence that exists in this 

intervening area (the western arm of the Amargosa Desert) indicates that the basin 

fill is mostly sedimentary, consisting of an upper permeable part, mostly 

alluvium, and a lower part, consisting mostly of tuffaceous sediments that 

probably are not very permeable owing to diagenetic alteration. In the eastern 

arm of the Amargosa desert, the few synextensional deposits that are exposed 

closely resemble those of basins to the south and east (category 3, above) and are 

likely to be permeable. These sediments overlie an impermeable early 

extensional sequence; hence the synextensional aquifer in this area may be 

separated from the underlying deep carbonate aquifer in at least part of the area by 

a leaky, heavily faulted and probably discontinuous confining unit. The central 

part of the Amargosa Desert is a north-trending trough, which is much deeper 

than the east and west arms of the Amargosa Desert basin-complex (Blakely and 

others, 1999). The basin fill in the northern part of this trough resembles that of 

the western arm of the Amargosa Desert (Oatfield and Czarnecki, 1989; Carr and 

others, 1995), whereas that of the southern part of the trough is more similar to 

the central Death Valley rhombochasm, but with a larger proportion of 

interbedded sandstones, which probably have moderate to low permeability (Naff, 

1973). In summary, the basin fill includes a widespread high quality alluvial 

aquifer in the east and west arms of the Amargosa Desert and in the northern part 

of the central trough. Permeability of the basin-fill decreases southward within 

the southern part of the Amargosa trough (Oatfield and Czarnecki, 1989; Naff, 

1973), based on the southward increasing abundance of altered nonwelded tuffs. 

Southward along the course of the Amargosa River, transmissive rocks likely are 

present again in a narrow corridor under this valley from just south of Eagle 

Mountain to the town of Shoshone, where exposed basin fill deposits consist of 

17 
less permeable lithologies (Morrison, 1999). Further south, the Amargosa River 

flows through basin fill of the China Ranch area, which is permeable except in a 

few areas dominated by playa sediments (Prave and McMackin, 1999; Morrison, 

1999). The locations of active springs and Pleistocene spring deposits along the 

course of the Amargosa River, as well as the stretches where this river flows most 

of the year, tend to mirror the changes in lithology of basin-filling deposits 

exposed along the course of this river. 

Late extensional/post-extensional sequence 

As discussed above, the synextensional sequence ends upsection at a contact that 

varies in age from ~10 Ma in the northeastern part of the Death Valley region to ~6 Ma in 

the vicinity of Death Valley, and to the west. East and north of the Death Valley 

rhombochasm, this overlying section is post-tectonic and consists largely of alluvium and 

lesser sediments of other types, mainly playa sediments. Within the Death Valley 

rhombochasm and to the west, these deposits are late extensional because extensional 

tectonism has continued in most of this area to the present, but the lithologies are 

basically the same as where this section is post-tectonic. Because the volumetrically 

dominant alluvial deposits of this youngest section largely postdate felsic pyroclastic 

volcanism in the region, the alluvium is not particularly tuffaceous. In most of the 

region, this alluvium has never been deeply buried and generally it is poorly 

consolidated. The majority of the late extensional/post-extensional sequence is therefore 

permeable. The major places where it is not permeable is in those areas where it consists 

mostly of playa sediments, such as much of the Furnace Creek basin (in the northernmost 

part of the Death Valley rhombochasm), and on the floor of Death Valley physiographic 

feature. 

Stratigraphic Setting of Tertiary Basin-Filling Deposits 

Regional ground-water flow models of the Death Valley region (IT Corp., 1996; 

D’Agnese and others, 1997) have described the Tertiary basin-filling rocks using a 

hydrogeologic unit that encompasses the entire undifferentiated sequence of Tertiary 

18 
basin fill. When modeled as a single hydrogeologic unit, these rocks appear in various 

stratigraphic scenarios, described below in order of their increasing complexity. 

In case 1 (fig. 2), Tertiary sedimentary rocks directly underlie Quaternary alluvium. 

Sedimentary sections are free of thick intervals of volcanic rocks, although the 

sedimentary units may have a volcaniclastic component. This is the case in Las Vegas 

Valley and the Indian Springs area where the Middle Miocene Horse Springs Formation 

is overlain by the Las Vegas Formation and Quaternary valley fill (Bohannon, 1984; 

Plume, 1989); in Hampel Wash and Rock Valley on the Nevada Test Site where the 

“rocks of Winapi Wash” and the “rocks of Pavits Spring” are overlain by Quaternary 

alluvium (Hinrichs, 1968); and in Kingston Wash and the northern part of the Shadow 

Valley basin where Tertiary conglomerates and megabreccias are overlain by Quaternary 

sediments (Friedmann, 1999; Prave and McMackin, 1999). 

In case 2 (fig. 2) Tertiary sedimentary rocks underlie a thick sequence of regionally 

extensive ash-flow tuffs derived from the southwestern Nevada volcanic field. The 

volcanic units are thick enough and well enough known to be modeled as their own 

hydrogeologic units (rather than being lumped with the Tertiary sediments as in case 3). 

Situations like case 2 occur in northwestern Frenchman Flat, Yucca Flat and beneath 

portions of southern Yucca Mountain (fig. 1). As the volcanic pile thickens proximal to 

the volcanic sources, boreholes do not penetrate the entire thickness of the volcanic 

rocks. Thus, the extent of the Tertiary sediments beneath the volcanic rocks is unknown 

close to the volcanic source. 

In case 3 (fig. 2), Tertiary sediments are interbedded with Tertiary volcanic rocks 

such that neither can be modeled as a separate hydrogeologic unit at the scale of a 

regional model. This situation occurs in much of the central Death Valley volcanic field, 

Furnace Creek Wash and the Amargosa Desert. This is the approach used in analyzing 

the outcrop and borehole data presented in this report. 

In case 4 (fig. 2), named volcanic units of the southwestern Nevada volcanic field 

interfinger at their distal edges with coeval Tertiary sediments. This is the most complex 

situation to model because of the potential for repetition of hydrogeologic units – 

something to be avoided. Situations like this occur in narrow bands near the margins of 

19 
CASE 1 CASE 2


CASE 3 CASE 4 

Qal 

Tm 

Tp 

Tc 

Tb 

Tvsu 

Qal 

Tsu 

Qal 

Tvu Tsu 

Tvu 

Tsu 

Tvsu 

Qal 

Tvsu 

Tsu 

Tsu 

Tc 

Tm 

Explanation 

Qal Quaternary alluvium 

Miocene volcanic rocks of the 

southwestern Nevada volcanic 

Tm Timber Mountain Group


Tp Paintbrush Group


Tc Crater Flat Group


Tb Belted Range Group


Types of Tertiary basin-filling 

Tvsu 	 Tertiary sedimentary and 

volcanic rocks, undivided 

Tsu 	 Tertiary sedimentary 

rocks, undivided 

Tvu 	 Tertiary volcanic rocks, 

undivided 

Figure 2. Diagrammatic examples of possible stratigraphic position of undifferentiated Tertiary 

volcanic and sedimentary rocks. 

20
the volcanic field; for example, in central Frenchman Flat and in some of the Nye County 

Early Warning Drilling Program (EWDP) boreholes to the south of Yucca Mountain. 

Methods of Study 

Outcrop Data 

Various workers have collected outcrop data from Tertiary strata during the course of 

studies attempting to reconstruct the Tertiary extensional history of the region. Outcrops 

of Tertiary strata are present mostly as stranded, rotated successions along range fronts. 

In a number of cases, the base of the Tertiary section is exposed, but not the top; this 

represents a possible source of bias in the data. Uncertainty also exists in how far to 

project the geology preserved in these outcrops into the subsurface. Tables 1 and 2 

present a compilation of outcrop data from throughout the region; a total of 33 localities 

are presented. Locations of the outcrop data are shown in figure 3. The data compilation 

includes total thickness, aggregate thickness of the volcanic component (including 

rhyolite and basalt flows, tuff, and air-fall deposits), aggregate thickness of the 

sedimentary component (including conglomerate, megabreccia, sandstone, siltstone, and 

limestone), and the thickness of the limestone portion of the sedimentary sequence. 

Subsurface Data 

Boreholes have been drilled in the Tertiary basin fill for various reasons including 

mineral exploration, water wells, test holes on the Nevada Test Site and as part of the site 

characterization at Yucca Mountain. Most of the boreholes do not penetrate the entire 

Tertiary section, leading to an underestimation in the total thickness of the section, and a 

bias towards data from the upper part of the section. Data quality is variable -- some of 

the data from the Amargosa Desert are from driller’s logs where the Tertiary sedimentary 

section may be reported as “gravel”, “colluvium” or “paleocolluvium”. Tables 3 and 4 

present a compilation of borehole data from throughout the region, a total of 64 localities. 

Borehole locations are shown in figure 3. Many more boreholes are available, but these 

holes were chosen to mimic the density of the outcrop data, provide a broad spatial 

distribution, include the deepest boreholes, and include those holes that were 

representative of a closely-spaced group of boreholes. 

21 
Figure 3. . 

22

0 25 50 75 OMETERS

ESMERALDA

COUNTY

NYE

COUNTY

LINCOLN

COUNTY

CLARK

COUNTY

INYO

COUNTY

SAN BERNARDINO

COUNTY

NEVADA CALIFORNIA

TEST SITE

NEVADA

15

95

Las 

Vegas

Pahrump

Mercury

Beatty

S

H

E

E

P

 RA

N

G

E

SPRING MOUNTAINS

DEATH

PA

NAMINT MOUNTAINS

FUNERAL MOUNTAINS VALLEY

45’

36o00’

45’30’15’

37o00’

15’

30’ 117o 15’ 00’ 45’ 30’ 15’ 116o00’ 45’ 30’ 15’

30’ 117o 15’ 00’ 45’ 30’ 15’ 116o00’ 45’ 115o 30’ 15’ 00’

45’36o00’

45’30’15’37o00’

15’

O18 O17

O19

O20

O21

O4

O3

O16

O22

O23

O26

O28 O27

O24

O25

O33

O31

O32

O5 O6

O2

O1

O30

O7 O8

O29

O15

O14

O13

O12

O11

O10 O9

B26

B5

B4

B1 B2

B3

B7

B38

B31 B23

B39

B33

B37

B38

B38

B38

B60 B57 B61

B62

B63

B28-30

B27

B53

B52

B51

B47

B48

B46 B45

B44 B43

B42

B41

B49

B50

B58

B59 B56

B55

B54

B19

B20

B21-25

B40

B18

B17

B12

B13

B11

B10

B8

B9

B14

B15

B16

Location map of outcrops and boreholes used in this study

KIL
Table 1. Location of outcrop data used for facies analysis 

Location Location Name Latitude Longitude Re

Number 

O1 Ryan Mine 36° 18’ 38” 116° 40’ 16” Niemi and others (2001), fig. 2; CO2 Eagle Mountain 36° 11’ 40” 116° 20’ 46” Niemi and others (2001), fig. 2 anO3 East of Resting Spring Range 36° 06’ 27” 116° 12’ 03” Niemi and others (2001), fig. 2 anO4 North of Resting Spring Range 36° 18’ 18” 116° 16’ 53” Cemen (1983); Denny and DreweO5 Black Mountains, section B-B' 36° 25’ 22” 116° 49’ 59” Niemi and others (2001), fig. 14; O6 Black Mountains, section E-E' 36° 24’ 26” 116° 47’ 36” Niemi and others (2001), fig. 14; O7 Black Mountains, section G-G' 36° 23’ 40” 116° 46’ 21” Niemi and others (2001), fig. 14; O8 Bat Mountain north 36° 21’ 04” 116° 28’ 59” Cemen and others (1985), fig. 4; O9 Hampel Wash 36° 41’ 04” 116° 05’ 28” Hinrichs (1968). 

O10 Mercury quadrangle 36° 42’ 43” 116° 55’ 53” Barnes and others (1982). O11 Nye Canyon 36° 56’ 28” 116° 49’ 59” Hinrichs and McKay (1965). O12 Buried Hills 37° 03’ 42” 116° 41’ 01” Tschanz and Pampeyan (1970); GO13 Gravel Canyon, Pintwater Range 36° 53’ 25” 116° 32’ 55” Longwell and others (1965); Guth O14 Black Hills basin 36° 42’ 59” 116° 15’ 11” Guth and others (1988). O15 Gass Peak basin 36° 25’ 55” 116° 10’ 14” Guth and others (1988). O16 Southern Resting Spring Range 35° 57’ 57” 116° 11’ 23” Wright (1999). O17 Kingston Wash 35° 38’ 54” 116° 54’ 49” Prave and McMackin (1999), fig. O18 Western Kingston Wash 35° 37’ 15” 116° 01’ 28” Prave and McMackin (1999), fig. O19 Dumont Hills, section E 35° 43’ 05” 116° 05’ 51” Prave and McMackin (1999), fig. O20 Dumont Hills, section C 35° 45’ 49” 116° 11’ 07” Prave and McMackin (1999), fig. O21 Amargosa Canyon, China Ranch 35° 48’ 32” 116° 12’ 31” Holm and others (1994), fig. 11. O22 Dublin Hills 35° 57’ 51” 116° 19’ 35” Chesterman (1973). O23 Salsberry Pass 35° 55’ 00” 116° 31’ 36” Wright and Troxel (1984). O24 Greenwater Range, Brown Peak 36° 08’ 06” 116° 23’ 49” Wright and others (1981). O25 Greenwater Range, Funeral Peak area 36° 13’ 00” 116° 34’ 27” Drewes (1963). O26 Copper Canyon basin 36° 08’ 55” 116° 43’ 57” Drewes (1963). O27 Trail Canyon 36° 18’ 13” 116° 57’ 44” McKenna and Hodges (1990). O28 Nova basin 36° 18’ 27” 116° 13’ 18” Hodges and others (1989). O29 Bat Mountain south 36° 19’ 24” 116° 30’ 05” Snow and Lux (1999), fig. 6; CemO30 Billie Mine 36° 20’ 17” 116° 40’ 59” Wright and others (1999). 

O31 Cottonwood Mountains, Section UH1 36° 57’ 10” 116° 26’ 48” Snow and Lux (1999), plate 2. O32 Cottonwood Mountains, Section UH2 36° 57’ 56” 116° 24’ 59” Snow and Lux (1999), plate 2. O33 Cottonwood Mountains, Section CC1 36° 35’ 29” 116° 16’ 59” Snow and Lux (1999), plate 2. 

23 
Table 2. Thickness data for lithologic types from measured sections and outcrop descriptions 

Thickness of sedimentary rocks, Thickness of volcanic roc

in m in m Location Total exposed 

Number thickness, in m All sedimentary Coarse-grained clastic Fine-grained Limestone All volcanic rocks Flows and welded tuff 

rocks rocks clastic rocks 

O1 925 O2 295 O3 295 O4 750 O5 950 O6 1790 O7 1700 O8 1282 O9 1780 

O10 785 O11 225 O12 1800 O13 1600 O14 1800 O15 293 O16 1500 O17 270 

625 590 23 12 330 0 295 268 27 0 0 0 280 0 0 0 15 0 550 400 150 0 200 0 555 220 335 0 395 395 

665 380 285 0 1105 1105 

0 0 0 0 1700 1700 

1279 777 282 220 3 0 1494 386 950 158 286 201 

625 395 0 230 160 160 

40 40 0 0 185 0 

1800 1800 0 0 0 0 1300 300 0 0 300 0 1300 1300 300 0 200 0 

285 49 44 192 8 0 

50 30 0 20 1450 1450 

270 150 120 0 0 0 

24 
Table 2. Thickness data for lithologic types from measured sections and outcrop descriptions -- Continued 

Thickness of sedimentary rocks, Thickness of volcanic roc

in m in m Location Total exposed 

Number thickness, in m All sedimentary Coarse-grained clastic Fine-grained Limestone All volcanic rocks Flows and welded tuff 

rocks rocks clastic rocks 

O18 450 O19 2200 O20 1000 O21 660 O22 335 O23 740 O24 2200 O25 1125 O26 3000 O27 635 O28 2300 O29 595 O30 1300 O31 635 O32 1010 O33 392 

450 450 0 0 0 0 

2200 2000 200 0 0 0 1000 900 100 0 0 0 

660 460 200 0 0 0 

23 0 0 0 312 312 55 0 55 0 685 665 

0 0 0 0 2200 2000 

60 0 60 0 1065 1065 

2900 2000 900 0 100 100 

0 0 0 0 635 635 

2200 2200 0 0 100 100 

585 490 0 95 10 0 

960 910 0 50 340 220 

560 560 0 0 75 75 

995 995 0 0 15 15 

375 350 15 10 7 7 

25 
Table 3. Location of borehole data used for facies analysis 

[Data are compiled from the following sources: USGS – NWIS: U.S. Geological Survey National Water Information System; State of 

Nevada: State of Nevada, Division of Water Resources, Well Driller’s Report; for cited publications, see “References” section of this 

report] 

Location 

Number Location Name Latitude Longitude Data Source 

B1 TW- F (1871 ft) 36° 45’ 34” 116° 6’ 59” USGS - NWIS 

B2 TH- 5 36° 46’ 1” 116° 1’ 3” USGS - NWIS 

B3 UE- 5c WW 36° 50’ 11” 115° 58’ 47” USGS - NWIS 

B4 Army 1 WW 36° 35’ 30” 116° 2’ 14” USGS - NWIS 

B5 Army 3 36° 32’ 38” 115° 46’ 46” USGS - NWIS 

B7 WW- C-1 36° 55’ 0” 116° 0’ 39” USGS - NWIS 

B8 UE- 6d 36° 59’ 5” 116° 3’ 32” USGS - NWIS 

B9 WW- 3 36° 59’ 43” 116° 3’ 29” USGS - NWIS 

B10 UE- 1h 37° 0’ 5” 116° 4’ 3” USGS - NWIS 

B11 UE- 1r WW 37° 1’ 42” 116° 3’ 33” USGS - NWIS 

B12 UE- 1d 37° 3’ 1” 116° 6’ 53” USGS - NWIS 

B13 UE- 1f 37° 2’ 46” 116° 6’ 49” USGS - NWIS 

B14 U - 3an 3 37° 3’ 54” 116° 2’ 14” USGS - NWIS 

B15 TH- 9 37° 3’ 11” 115° 59’ 18” USGS - NWIS 

B16 U - 3mh (NT 1008 ) 37° 1’ 57” 115° 59’ 14” USGS - NWIS 

B17 UE- 9 ITS US-U-22 37° 8’ 7” 116° 2’ 17” USGS - NWIS 

B18 U - 2df (NT 604 ) 37° 8’ 22” 116° 5’ 15” USGS - NWIS 

B19 U -12e.03-1 37° 11’ 22” 116° 12’ 22” USGS - NWIS 

B20 Effinger 4 37° 10’ 59” 116° 10’ 30” USGS - NWIS 

B21 Whiterock Springs 3 37° 11’ 58” 116° 7’ 55” USGS - NWIS 

B22 Whiterock Springs 3A 37° 11’ 59” 116° 7’ 52” USGS - NWIS 

B23 Whiterock Springs 1 37° 12’ 4” 116° 7’ 55” USGS - NWIS 

B24 USGS Shot Hole 37° 12’ 5” 116° 8’ 2” USGS - NWIS 

B25 Whiterock Springs 2 37° 12’ 10” 116° 7’ 50” USGS - NWIS 

B26 Watertown 2 WW 37° 14’ 39” 115° 48’ 00” USGS - NWIS 

B27 Amargosa Farms 45672 36° 54’ 8” 116° 49’ 1” State of Nevada 

B28 Amargosa Farms 40410 36° 54’ 7” 116° 49’ 1” State of Nevada 

B29 Amargosa Farms 51620 36° 54’ 7” 116° 48’ 60” State of Nevada 

26 
Table 3. Location of borehole data used for facies analysis - continued 

[Data are compiled from the following sources: USGS – NWIS: U.S. Geological Survey National Water Information System; State of 

Nevada: State of Nevada, Division of Water Resources, Well Driller’s Report; for cited publications, see “References” section of this 

report] 

Location Location Name Latitude Longitude Data Source Number 

B30 Amargosa Farms 66226 36° 53’ 42” 116° 49’ 00” State of Nevada 

B31 Janet Aubrey 36° 19’ 49” 115° 20’ 18” USGS - NWIS 

B32 C.R. Coke 36° 19’ 8” 115° 16’ 1” USGS - NWIS 

B33 Laurence Barringer 36° 16’ 45” 115° 16’ 49” USGS - NWIS 

B34 Unknown 36° 18’ 15” 115° 15’ 9” USGS - NWIS 

B35 Don W. Charleboix 36° 17’ 32” 115° 14’ 21” USGS - NWIS 

B36 J.J. Fairchild 36° 17’ 9” 115° 14’ 53” USGS - NWIS 

B37 Leon Bright 36° 16’ 36” 115° 15’ 12” USGS - NWIS 

B38 H. & Edna Bierbach 36° 18’ 16” 115° 24’ 13” USGS - NWIS 

B39 CNLV Leavitt 36° 13’ 49” 115° 7’ 5” USGS - NWIS 

B40 UE- 8e (2470 ft) 37° 10’ 14” 116° 5’ 16” USGS - NWIS 

B41 US Borax Exploration SEM-5 36° 8’ 53” 116° 18’ 41” State of Nevada 

B42 US Borax Exploration AM-2 36° 12’ 1” 116° 24’ 14” State of Nevada 

B43 US Borax Exploration L-3 36° 14’ 27” 116° 29’ 27” State of Nevada 

B44 US Borax Exploration S-2 36° 17’ 13” 116° 30’ 48” State of Nevada 

B45 US Borax Exploration NA-8 36° 21’ 43” 116° 26’ 19” State of Nevada 

B46 US Borax Exploration GS-3 

B47 USGS Tracer Study 

Exploratory Hole 3 

B48 Nye County Land Co. 

Amargosa Farms 9343 

B49 Spring Meadows, Inc. 

Amargosa Farms 12942 

B50 Nye County Land Co. 

Amargosa Farms 9028 

B51 Michael Gilgan Amargosa 

Farms 6943 

B52 James E. Owens Amargosa 

Farms 20042 

B53 US Borax Exploration NT-1 

B54 Felderhoff Federal 25-1 

36° 19’ 58” 116° 17’ 54” State of Nevada 

36° 32’ 12” 116° 13’ 36” Johnston (1968) 

36° 23’ 48” 116° 18’ 12” State of Nevada 

36° 27’ 52” 116° 20’ 22” State of Nevada 

36° 28’ 50” 116° 20’ 28” State of Nevada 

36° 28’ 33” 116° 26’ 43” State of Nevada 

36° 31’ 44” 116° 31’ 9” State of Nevada 

36° 31’ 47” 116° 34’ 0” State of Nevada 

36° 35’ 6” 116° 23’ 1” Carr and others (1995) 

27 
Table 3. Location of borehole data used for facies analysis – continued 

[Data are compiled from the following sources: USGS – NWIS: U.S. Geological Survey National Water Information System; State of 

Nevada: State of Nevada, Division of Water Resources, Well Driller’s Report; for cited publications, see “References” section of this 

report] 

Location 

Number Location Name Latitude Longitude Data Source 

B55 Lawrence Funder Amargosa 36° 35’ 19” 116° 25’ 8” State of Nevada 

Farms 5926 

B56 Desert Farms Amargosa Farms 36° 38’ 22” 116° 24’ 30” State of Nevada 

7702 

B57 US Borax Exploration NA-6 36° 41’ 31” 116° 41’ 5” State of Nevada 

B58 NC-EWDP-5S 36° 40’ 12” 116° 22’ 37” State of Nevada 

B59 NC-EWDP-2D 36° 39’ 39” 116° 27’ 57” State of Nevada 

B60 NC-EWDP-1S 36° 42’ 33” 116° 35’ 18” State of Nevada 

B61 Bond Gold Bullfrog Inc. 36° 48’ 53” 116° 52’ 8” State of Nevada 

BGMW- 3 

B62 Bond Gold Bullfrog Inc. ETW 36° 51’ 10” 116° 49’ 30” State of Nevada 

II- (PW-2) 

B63 Beatty Water District 36° 54’ 49” 116° 45’ 13” State of Nevada 

Amargosa Farms 52728 

28 
Table 4. Thickness data for lithologic types from boreholes. 

Thickness of sedimentary rocks, Thickness o

Location Total exposed in m 

Number thickness, in m All sedimentary rocks Coarse-grained clastic Fine-grained Limestone All volcanic Flows and w

rocks clastic rocks rocks 

B1 436 436 0 436 0 0 0 B2 113 0 0 0 0 113 11B3 421 0 0 0 0 421 42B4 76 0 0 0 0 76 76 B5 136 0 0 0 0 136 13B6 421 0 0 0 0 421 42B7 332 0 0 0 0 332 0 B8 898 872 872 0 0 26 0 B9 244 244 244 0 0 0 0 

B10 204 204 204 0 0 0 0 B11 3 3 3 0 0 0 0 B12 67 0 0 0 0 67 0 B13 73 52 52 0 0 21 21 B14 509 0 0 0 0 509 50B15 311 0 0 0 0 311 0 B16 20 20 20 0 0 0 0 B17 358 0 0 0 0 358 35B18 2 0 0 0 0 2 2 B19 220 0 0 0 0 220 22B20 3 0 0 0 0 3 3 B21 13 0 0 0 0 13 13 B22 3 0 0 0 0 3 3 B23 22 0 0 0 0 22 22 B24 32 0 0 0 0 32 32 B25 26 0 0 0 0 26 26 B26 187 0 0 0 0 187 18B27 393 0 0 0 0 393 39

29 
Table 4. Thickness data for lithologic types from boreholes -- Continued. 

Thickness of sedimentary rocks, Thickness o

Location Total exposed in m 

Number thickness, in m All sedimentary rocks Coarse-grained clastic Fine-grained Limestone All volcanic Flows and w

rocks clastic rocks rocks 

B28 183 0 0 0 0 183 18B29 95 0 0 0 0 95 94 B30 346 6 0 6 0 340 34B31 166 166 166 0 0 0 0 B32 104 104 0 104 0 0 0 B33 47 47 7 40 0 0 0 B34 51 51 0 51 0 0 0 B35 69 69 18 51 0 0 0 B36 145 145 120 25 0 0 0 B37 30 30 8 22 0 0 0 B38 52 52 52 0 0 0 0 B39 304 304 6 298 0 0 0 B40 37 16 0 16 0 21 0 B41 263 252 252 0 0 11 5 B42 390 255 29 226 0 135 13B43 563 450 224 192 34 113 42 B44 534 515 169 346 0 19 19 B45 583 583 375 208 0 0 0 B46 604 604 0 604 0 0 0 B47 92 90 90 0 0 2 2 B48 179 179 52 84 43 0 0 B49 248 248 0 154 94 0 0 B50 179 179 9 114 56 0 0 B51 90 90 0 90 0 0 0 B52 124 124 100 24 0 0 0 B53 468 300 234 0 66 168 16B54 529 370 361 0 9 159 15

30 
Table 4. Thickness data for lithologic types from boreholes – Continued. 

Thickness of sedimentary rocks, Thickness o

Location Total exposed in m 

Number thickness, in m All sedimentary rocks Coarse-grained clastic Fine-grained Limestone All volcanic Flows and w

rocks clastic rocks rocks 

B55 175 175 23 140 12 0 0 B56 187 187 107 80 0 0 0 B57 170 54 54 0 0 116 11B58 278 251 101 50 0 27 0 B59 142 112 112 0 0 30 0 B60 715 590 337 253 0 125 78 B61 103 103 103 0 0 0 0 B62 172 172 172 0 0 0 0 B63 151 123 95 0 28 28 28 B64 427 0 0 0 0 427 42

31 
Tertiary Thickness Modeled from Gravity Data 

Inverse modeling of gravity data from the region (fig. 4) has greatly contributed to 

the knowledge of the Tertiary tectonic style and the subsurface configuration of the 

Tertiary basins (Blakely and others, 1999). Such models can be used to estimate the 

thickness of Tertiary basin fill, but with some caveats. The model estimates the thickness 

of Cenozoic deposits based on a computational inversion (Jachens and Moring, 1990) of 

gravity data (Saltus and Jachens, 1995; Blakely and others, 1998; Blakely and others, 

1999) combined with density-depth assumptions. The models separate the pre-Cenozoic 

“basement” from the entire Cenozoic basin fill, including Tertiary and Quaternary 

sedimentary and volcanic rocks. In areas that are far from volcanic sources, such as the 

Pahrump Valley, portions of the Amargosa Valley and the Las Vegas Valley, the 

modeled thickness may approximate the thickness of the Tertiary basin-filling rocks. 

However, the gravity models do not separate out volcanic rocks where they are thick 

enough to be assigned their own hydrogeologic unit. Thus, the thickness of the Tertiary 

section as described by the gravity model is not indicative of the thickness of the 

undifferentiated Tertiary basin-filling rocks when close to volcanic fields. 

32 
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Outcrop of pre-Cenozoic rocks

EXPLANATION

State boundary

County boundaryInterstate HighwayNevada Test Site boundaryState Highway

15

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Location of outcrop observation or measured section

Thickness of Tertiary basin-filling rocks, based on gravity model of Blakely (1999).

0 - 500 m500 - 1000 m1000 - 1500 m1500 - 2000 m2000 - 2500 m

Location of borehole

Approximate limit of southwestern Nevada volcanic field

Caldera boundary

> 2500 m

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nozoic basin fill based on gravity model.

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Regional Facies Trends 

Thickness 

Thickness of undifferentiated Tertiary basin fill as measured from boreholes and 

outcrop is skewed toward outcrop data (fig. 5); most of the boreholes are shallow and 

underestimate the total thickness of the unit. The contoured data show bull’s eye type 

trends due to sparse data coverage. 

Thickness estimated from an inversion of the gravity data (Blakely and others, 1998; 

1999) (fig. 4) better delineates the Tertiary basins, but includes all Cenozoic rocks. In 

areas that are far from volcanic sources, the modeled thickness may approximate the 

thickness of the Tertiary basin-filling rocks. Modeling of regional gravity data has 

revealed the presence of a number of deep troughs that are likely to be filled with Tertiary 

sedimentary rock (Blakely and others, 1999). Gravity modeling of the Stewart ValleyPahrump strike-slip fault zone (roughly parallel to the California-Nevada boundary on 

figure 5) shows that the fault is associated with complex variations in the elevation of the 

Tertiary-Paleozoic contact (Blakely and others, 1998). In the Pahrump Valley, the 

Stewart Valley-Pahrump fault zone forms a buried transpressional bedrock ridge 

separating two steep-sided, probably fault-bounded Tertiary basins (Blakely and others, 

1998). The basins are interpreted to be transtensional basins associated with right steps 

in this fault system (Wright, 1989; Blakely and others, 1998). To the northwest in the 

Amargosa Valley, this fault zone forms another northwest trending bedrock ridge that 

separates two northwest trending basins (Blakely and others, 1999). Modeling of 

regional gravity data from Death Valley reveals a number of narrow, step-sided, 

sediment-filled troughs (Blakely and others, 1999). 

Compositional Trends 

Figures 6 and 7 show the distribution of sedimentary and volcanic portions of the 

Tertiary basin fill, respectively. Depocenters for Tertiary sedimentary rocks include 

coarse conglomerates in the Kingston Wash area (southern edge of fig. 6) and the Nova 

basin to the west of the Panamint Mountains, as well as more localized sedimentary 

successions in Furnace Creek Wash, in the southern part of the Nevada Test Site, and in 

34 
Figure 5. ertiary basin fill based on measurements in outcrop and in boreholes.

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Figure 6. ertiary sedimentary rocks based on measurements at outcrops and in boreholes.

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Figure 7. ertiary volcanic rocks outside the southwestern Nevada volcanic field.

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Thicknexclusvolcanboreho

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Lincoln County. The extent of sediments under the volcanic pile of the southwestern 

Nevada volcanic field is largely unknown. Shallow boreholes in the northwest part of the 

Las Vegas Valley do not penetrate the thick Tertiary section in the center of the valley 

(Longwell and others, 1965; Plume, 1989). The extensive Tertiary sedimentary rocks 

that underlie Death Valley are here represented by a single outcrop data point – the 

uplifted Copper Canyon basin. 

Tertiary volcanic rocks exclusive of the named volcanic rocks from the southwestern 

Nevada volcanic field are primarily aligned along a northwest-southeast trend (fig. 7) that 

is associated with the Furnace Creek fault and the central Death Valley volcanic-plutonic 

province. Tertiary sedimentary and volcanic rocks occupy different depocenters; 

primarily the result of the sweep of tectonism and volcanism across this region that 

results in spatially variable and shifting locus of deposition through time. 

The distribution of Tertiary limestone (fig. 8) varies both spatially and 

stratigraphically throughout the region. North of Las Vegas and to the north and west of 

Mercury, the thickest Tertiary limestones are present in the lower to middle Miocene 

rocks that are equivalent to the "rocks of Pavits Spring" on the Nevada Test Site. Late 

Oligocene to Early Miocene limestones are exposed at Bat Mountain (Cemen and others, 

1999). In the central Amargosa Valley, a shallow Tertiary limestone of unknown but 

probably younger age is present in many of the boreholes in the Amargosa Farms area. 

Tertiary basins dominated by sedimentary rocks (fig. 9) include the Amargosa Desert, 

the Las Vegas Valley, the Pahrump Valley and the Shadow Valley basin/Kingston 

Wash/China Ranch area. Death Valley and the northern half of the Pahrump Valley are 

not well represented due to lack of data. A breakdown of coarse-grained (sand-sized and 

larger) versus fine-grained (smaller than sand) sedimentary rocks is also shown on figure 

9. Grain size information is variable in quality and depends on the detail present in 

published descriptions. There are some bull’s-eyes based on limited, isolated data, but 

some trends are recognizable as well. The transition from coarse-grained to fine-grained 

sedimentary rocks in the northwest edge of the Las Vegas Valley, previously documented 

by Plume (1989) is evident here. The coarse synextensional gravels and megabreccias in 

the Kingston Wash area are also evident. The Amargosa Desert shows a complex pattern 

38 
Figure 8. ertiary limestones based on measurements at outcrops and in boreholes.

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Figure 9. ertiary section and grain size characteristics.

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ProporTertiara percthe se

Proporrocks, total tportion 

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40

Relative proportion of sedimentary rocks in the T

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of grain size distribution, in part reflecting the presence of fine-grained sediments in the 

basin center. 

Tertiary basins dominated by volcanic rocks (fig. 10) include the margins of the 

southwestern Nevada volcanic field and the central Death Valley volcanic-plutonic 

province. Thick sequences of regionally extensive ash-flow tuffs derived from the 

southwestern Nevada volcanic field known to be present beneath Yucca Flat, Crater Flat 

and at Yucca Mountain are not shown on figure 10. These volcanic units are thick 

enough and well enough known to be modeled as their own hydrogeologic units, rather 

than being lumped with coeval Tertiary sediments. When rhyolite and basalt lava flows 

and ash-flow tuffs are separated from airfall tuff and ash deposits (contours on figure 10), 

the thick accumulations of volcanic rocks are seen to be dominated by the tuffs and lava 

flows, as expected proximal to volcanic source areas. Thinner, distal sections are 

dominated by airfall material, such as in the Ash Meadows area of the Amargosa Desert. 

Amargosa Desert Borehole Data 

A preliminary compilation of data from 188 boreholes in the Amargosa Desert 

compliments surface and subsurface geologic investigations conducted in the area at the 

regional scale (1:250,000). Borehole data are being used to identify Quaternary and 

Tertiary volcanic and sedimentary rocks within the basin, classify them into 

hydrogeologic units, and map the subsurface distribution of these units. The principal 

hydrogeologic units that can be recognized and correlated in the Amargosa Desert are: 

• Fine-grained alluvium including playa deposits and basin-axis mudstone; 

• Quaternary and Tertiary coarse-grained alluvium (sand and gravel) including near 

surface unconsolidated gravels and sands and late-stage basin fill; 

• Quaternary-Tertiary spring/lacustrine deposits including an upper limestone 

aquifer; 

41 
Figure 10. ertiary section and rock type.

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Relative proportion of volcanic rocks in the T

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• Basalt; 

• Silicic volcanic welded tuffs, subdivided when adequate data are available; 

• A consolidated (mostly Tertiary) mixed unit of clastic and volcaniclastic rocks. 

A principal difficulty in the initial compilation and stratigraphic analyses of 

borehole data from the Amargosa Desert involved integrating subsurface lithologic data 

known to be of high quality, such as those data from the Nye County Early Warning 

Drilling Program (EWDP) boreholes to the south of Yucca Mountain and the Felderhoff 

boreholes (Carr and others, 1995) with information contained in driller’s logs that are 

source of data for many of the holes in the Amargosa Farms area (Oatfield and 

Czarnecki, 1989). Many of the boreholes in the area (fig. 11) are shallow; deeper 

boreholes provide important control points. Subsurface geologic units are defined in 

generalized lithologic terms, based on characteristics of hydrogeologic importance such 

as permeability and are compared where possible to existing surficial maps to define the 

spatial extents of the major lithologic units, including alluvial channels, spring deposits, 

outcrops of freshwater limestones, basin center and playa deposits, and transitions from 

coarse-grained to fine-grained clastic sedimentary deposits. 

Two preliminary stratigraphic sections across the Amargosa Desert (figs. 12 and 

13) display some of the stratigraphic complexity and facies trends within the basin. The 

east-west section (fig. 12) highlights the segmented nature of the basin: a relatively thick 

section of Tertiary volcanic rocks along the northeastern flank of the Funeral Mountains 

gives way to sections that are dominated by shallow Tertiary limestones in the Amargosa 

Farms area. Boreholes on the eastern end of the section penetrate local basalt flows. 

Many of the boreholes at the northern end of the north-south cross section (fig. 13) 

penetrate volcanic rocks associated with the southwestern Nevada volcanic field. These 

volcanic rocks are absent beyond the central part of the section, giving way again to the 

shallow Tertiary limestones in the Amargosa Farms area, thicker limestone-poor sections 

to the south, and at the southern end, a section that contains volcanic rocks associated 

with the central Death Valley volcanic field. 

43 
117o00' 116o 45' 116o 30' 116o 15' 116o00' 

37o00' 

36o45' 

36o30' 

36o15' 

36o00' 

A A' 

B 

B' 

D E AT H 

F U NERAL MOUNTAINS 

V ALLEY 

PAHRUMP 

VALLEY 

N EVAD A 

C A L IFORNIA 

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VALLE Y

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Figure 11. Location map of boreholes and stratigraphic cross sections in the vicinity of the Amargosa Desert. 

44

f

45 

Depth, in m

A 

AF8-78 BorNT-1 BorST-2 BorNA-10 AF7285 AF51882 AF8482 AF12841 DOE48842 

Playa Quaternary-Tertiary Alluvium 

Basalt 

Tertiary clastic sedimentary rocks, undiff. 

Tertiary volcanic rocks, undif. 

Tertiary limestone Older Tertiary volcanic rocks, undiff. Paleozoic carbonate rocks, undiff. 

Figure 12. Stratigraphic cross section A-A'. Section is oriented approximately east-west through the central portion of the Amar

See fig. 11 for section line. 
BorGS-3 AF9343 AF10387 AF12942 FF25 FF5 Nye2DB Nye3D Nye1DX BorNA-6 BorBT-3 BorNA-4 

B' 

Playa Quaternary-Tertiary Alluvium Basalt Tertiary clastic sedimentary rocks, undiff. 

Tertiary volcanic rocks, undiff. 

Tertiary limestone 

Older Tertiary volcanic rocks, undiff. 

Paleozoic carbonate rocks, undiff. 

ction B-B'. Section is oriented approximately north-south along the axis of the Amargosa Desert. See fig. 11 for section line. 

46

Summary of Material Properties 

On the basis of the distribution of sedimentary and volcanic components and 

structural setting of the Tertiary basin-filling rocks of the Death Valley ground-water 

basin, five broad zones have been delineated (fig. 14) that represent areas with potentially 

distinct material properties and potentially different hydraulic properties. Each of these 

zones is discussed below. 

Zone 1: This zone includes the eastern part of region. Stratigraphic successions 

consist of early extensional to synextensional sediments that are largely free of volcanic 

rocks and occupy regions that have been moderately extended. This region includes the 

Las Vegas Valley, the Indian Springs area and valleys to the north of Indian Springs and 

the southeastern portion of the Nevada Test Site. The Pahrump Valley is shown as a sub 

region. Tertiary strata in this basin are not as well characterized, but the basin is far 

enough away from volcanic fields that the sedimentary successions are likely to be 

similar to those elsewhere in this zone. 

Zone 2: This zone corresponds to marginal parts of the southwestern Nevada 

volcanic field, where Tertiary sedimentary rocks underlie a thick sequence of regionally 

extensive ash-flow tuffs. Volcanic rocks penetrated by boreholes may not have been 

explicitly identified, but are probably derived from the southwestern Nevada volcanic 

field. 

Zone 3: This zone includes synextensional sediments related to extreme 

extension. Coarse synextensional gravels and megabreccias characterize these sections. 

Included in this region are the Shadow Valley supradetachment basin, Death Valley, and 

the Nova basin to the west of Death Valley. 

Zone 4: This zone includes the synextensional volcano-sedimentary trough that 

incorporates the central Death Valley volcanic-plutonic field and the Furnace Creek 

basin. Stratigraphic successions are a mixed assemblage of sedimentary and volcanic 

rocks whose deposition was closely associated with movement along the Furnace Creek 

fault zone. 

47

Figure 14. Map showing location of zones that may define major regional differences in material properties.

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Zone 5: Stratigraphic successions within this zone are similar only in their 

generally high stratigraphic and structural complexity. The region is characterized by its 

wide variety of sedimentary rocks, including coarse-and fine-grained alluvial fill, 

lacustrine deposits and playa deposits, fluvially reworked tuffs and tuffaceous 

sedimentary rocks that span an age range from Oligocene to the Pliocene. Volcanic rocks 

are present in varying proportions. These rocks have been affected both by extension and 

by strike-slip deformation associated with the Stewart Valley-Pahrump fault zone. 

The sum effect of all of the above is that a few of the basin fills are fairly permeable 

top to bottom and a few are impermeable top to bottom. But most of the basin fills could 

either be represented by an aquifer overlying a leaky confining unit, or alternatively, by a 

single unit that decreases in permeability with depth. 

49 
References Cited 

Barnes, Harley, Ekren, E.B., Rogers, C.L., and Hedlund, D.C., 1982, Geologic and tectonic maps of the 

Mercury quadrangle, Nye and Clark Counties, Nevada: U.S. Geological Survey Miscellaneous 

Investigations Map I-1197, 1 sheet, scale 1:24,000. 

Bedinger, M.S., Langer, W.H., and Reed, J.E., 1989, Ground-water hydrology, in Bedinger, M.S., Sargent, 

K.A., and Langer, W.H., eds., Studies of geology and hydrology in the Basin and Range Province, 

Southwestern United States, for isolation of high-level radioactive waste—Characterization of the 

Death Valley region, Nevada and California: U.S. Geological Survey Professional Paper 1370–F, 

p. 28–35. 

Blakely, R.J., Jachens, R.C., Calzia, J.P., and Langenheim, V.E., 1999, Cenozoic basins of the Death 

Valley extended terrane as reflected in regional gravity anomalies, in Wright. L.A., and Troxel, B.W., 

eds., Cenozoic Basins of the Death Valley Region: Geological Society of America Special Paper 333, 

p. 1-16, Boulder, Colorado. 

Blakely, R.J., Langenheim, V.E., Ponce, D.A., and Dixon, G.L., 2000, Aeromagnetic Survey of the 

Amargosa Desert, Nevada and California — A Tool for Understanding Near-Surface Geology and 

Hydrology: U.S. Geological Survey Open-File Report 00-188, 39 p., 2 plates. 

Blakely, R.J., Morin, R.L., McKee, E.H., Schmidt, K.M., Langenheim, V.E., and Dixon, G.L., 1998, Threedimensional model of pre-Cenozoic basement beneath Amargosa Desert and Pahrump Valley, 

California and Nevada — Implications for tectonic evolution and water resources: U.S. Geological 

Survey Open-File-Report 98-496, 29 p. 

Blankennagel, R.K., and Weir, J.E., Jr., 1973, Geohydrology of the eastern part of Pahute Mesa, Nevada 

Test Site, Nye County, Nevada: U.S. Geological Survey Professional Paper 712-B, 35 p. 

Bohannon, R.G., 1984, Nonmarine sedimentary rocks of Tertiary age in the Lake Mead Region, 

southeastern Nevada and northwestern Arizona: USGS Professional Paper 1259, 72 p., 1 plate. 

Byers, F.M. Jr., Carr, W.J., Orkild, P.P., Quinlivan, W.D., and Sargent, K.A., 1976, Volcanic suites and 

related cauldrons of the Timber Mountain-Oasis Valley caldera complex, southern Nevada: U.S. 

Geological Survey Professional Paper 919, 70 p. 

Carr, W.J., Keller, S.M., and Grow, J.A., 1995, Lithologic and geophysical logs of drill holes Felderhoff 

Federal 5-1 and 25-1, Amargosa Desert, Nye County, Nevada: U.S. Geological Survey Open-File 

Report 95-155, 14 p. 

Cemen, Ibrahim, 1983, Stratigraphy, geochronology and structure of the selected areas of the northern 

Death Valley region, eastern California-western Nevada, and implications concerning Cenozoic 

tectonics of the region: University Park, Penn., Pennsylvania State University Ph.D. thesis, 235 p, 1 

map, scale 1:12,000. 

Cemen, Ibrahim, 1999, Tectonostratigraphic relationship between the Cenozoic sedimentary successions 

of the southern Funeral Mountains, Furnace Creek basin, Eagle Mountain, and the north end of the 

Resting Spring range, in Slate, J.L., ed., Proceedings of conference on status of geologic research 

and mapping in Death Valley National Park, Las Vegas, Nevada, April, 9-11, 1999: U.S. Geological 

Survey Open-File Report 99-153, p. 56-57. 

50 
Cemen, Ibrahim, Wright, L.A., Drake, R.E. and Johnson, F.C., 1985, Cenozoic sedimentation and sequence 

of deformational events at the southeastern end of the Furnace Creek strike-slip fault zone, Death 

Valley region, California, in Biddle, K.T. and Christie-Blick, Nicholas, eds., Strike-slip deformation and 

basin formation: Society of Economic Paleontologists and Mineralogists Special Publication 37, p. 

127-141. 

Cemen, Ibrahim, Wright, L.A., and Prave, A.R., 1999, Stratigraphy, and tectonic implications of the latest 

Oligocene and early Miocene sedimentary succession, southernmost Funeral Mountains, Death 

Valley region, California, in Cenozoic basins of the Death Valley region: Wright, L.A. and Troxel, 

B.W., eds., Geological Society of America Special Paper 333, p. 65-86. 

Chesterman, C.W., 1973, Geology of the northeast quarter of Shoshone quadrangle, Inyo County, 

California: California Division of Mines and Geology Map Sheet 18, 1 sheet, scale1:24,000. 

D’Agnese, F.A., Faunt, C.C., Turner, A.K., and Hill, M.C., 1997, Hydrogeologic evaluation and numerical 

simulation of the Death Valley regional ground-water system, Nevada and California: U.S. Geological 

Survey Water-Resources Investigation Report 96-4300, 124 p. 

Denny, C.S., and Drewes, Harald, 1965, Geology of the Ash Meadows Quadrangle, Nevada-California — 

the history of a desert basin and its bordering highlands: U.S. Geological Survey Bulletin 1181-L, 56 

p., 1 plate, scale 1:62,500. 

Dudley, W.W., Jr., and Larson, J.D., 1976, Effect of irrigation pumping on desert pupfish habitats in Ash 

Meadows, Nye County, Nevada: U.S. Geological Survey Professional Paper 927, 52 p. 

Drewes, Harald, 1963, Geology of the Funeral Peak quadrangle, California, on the east flank of Death 

Valley: U.S. Geological Survey Professional Paper 413, 78 p., 2 plates, scale 1:62,500. 

Ekren, E.B., Orkild, P.P., Sargent, K.A., and Dixon, G.L., 1977, Geologic map of Tertiary rocks, Lincoln 

County, Nevada: U.S. Geological Survey Miscellaneous Investigations Series Map I-1041, scale 

1:250,000. 

Fowler, T.K., Jr., and Calzia, J.P., 1999, Kingston Range detachment fault, southeastern Death Valley 

region, California — relation to Tertiary deposits and reconstruction of initial dip, in Wright, L.A., and 

Troxel, B. W., eds., Cenozoic basins of the Death Valley region: Geological Society of America 

Special Paper 333, p. 245-257. 

Friedmann, S.J., 1999, Sedimentology and stratigraphy of the Shadow Valley basin, eastern Mojave 

Desert, California, in Cenozoic basins of the Death Valley region: Wright, L.A. and Troxel, B.W., eds., 

Geological Society of America Special Paper 333, p. 213-244. 

Fridrich, C.J., 1999, Tectonic evolution of the Crater Flat basin, Yucca Mountain region, Nevada, in 

Wright, L.A., and Troxel, B.W., eds., Cenozoic basins of the Death Valley region: Geological Society 

of America Special Paper 333, p.169-195. 

Fridrich, C.J., Dudley Jr., W.W., and Stuckless, J.S., 1994, Hydrogeologic analysis of the saturated-zone 

ground-water system, under Yucca Mountain, Nevada: Journal of Hydrology, v. 154, p. 133-168. 

Fridrich, C.J., Minor, S.A., and Mankinen, E.A., 1999, Geologic evaluation of the Oasis Valley basin, Nye 

County, Nevada: U.S. Geological Survey Open-File Report 99-0533-A, 55 p. 

51 
Fridrich, C.J., Minor, S.A., Ryder, P.L., and Slate, J.L., with contributions form Warren, R.G., Hildenbrand, 

T.G., Sawyer, D.A., and Orkild, P.P., 1999, Geologic map of the Oasis Valley Basin and vicinity, Nye 

County, Nevada: U.S. Geological Survey Open-File Report 99-533-B, scale 1:62,500. 

Fridrich, C.J., Thompson, R.A., Machette, M.N., and Miggins, D.P., 2000, Late Cenozoic stratigraphic 

record of tectonic evolution, volcanism, and climate change in the Death Valley region, California and 

Nevada: EOS, Transactions, American Geophysical Union, v. 81, p. F1127. 

Fridrich, C.J., Whitney, J.W., Hudson, M.R., and Crowe, B.M., 1999, Space-time patterns of Late 

Cenozoic extension, vertical-axis rotation, and volcanism in the Crater Flat basin, southwest Nevada, 

in Wright, L.A., and Troxel, B.W., eds., Cenozoic basins of the Death Valley region: Geological 

Society of America Special Paper 333, p. 197-212. 

Grauch, V.J.S., Sawyer, D.A., Fridrich, C.J., and Hudson, M.R., 1999, Geophysical framework of the 

southwestern Nevada volcanic field and hydrogeologic implications: U.S. Geological Survey 

Professional Paper 1608, 39 p. 

Greene, R.C., 1997, Geology of the northern Black Mountains, Death Valley, California: U.S. Geological 

Survey Open-File Report 97-79, 82 p., 3 plates, scale 1:24,000. 

Guth, P.L., Schmidt, D.L., Deibert, Jack, and Yount, J.C., 1988, Tertiary extensional basins of 

northwestern Clark County, Nevada, in Weide, D.L., and Faber, M.L., eds., This Extended Land – 

Geological journeys in the southern Basin and Range: Geological Society of America Cordilleran 

Section Field Trip Guidebook, p. 239-254. 

Harrill, J.R., 1986, Ground-water storage depletion in Pahrump Valley, Nevada-California, 1962-75: U.S. 

Geological Survey Water-Supply Paper 2279, 52 p., 3 plates. 

Hinrichs, E.N., 1968, Geologic map of the Camp Desert Rock quadrangle, Nye County, Nevada: U.S. 

Geological Survey Geologic Quadrangle Map GQ-726, scale 1:24,000. 

Hinrichs, E.N. and McKay, E.J., 1965, Geologic map of the Plutonium Valley quadrangle, Nye and Lincoln 

Counties, Nevada: U.S. Geological Survey Geologic Quadrangle Map GQ-384, scale 1:24,000. 

Hodges, K.V., McKenna, L.W., Stock, J., Knapp, J., Page, L., Sternlof, K., Silverberg, D., Wust, G., and 

Walker, J.D., 1989, Evolution of extensional basins and Basin and Range topography west of Death 

Valley, California: Tectonics, v. 8, p. 453-467, 1 plate. 

Holm, D.K., Pavlis, T.L., and Topping, D.J., 1994, Black Mountains crustal section, Death Valley extended 

terrane, California, in McGill, S.F., and Ross, T.M., eds., Geological investigations of an active 

margin: Geological Society of America Cordilleran Section Fieldtrip Guidebook, Trip 2, San 

Bernardino, California, p. 31-54. 

Hunt, C.B., Robinson, T.W., Bowles, W.A., and Washburn, A.L., 1966, Hydrologic basin, Death Valley, 

California: U.S. Geological Survey Professional Paper 494-B, 138 p., with 3 plates. 

IT Corporation, 1996, Underground Test Area Subproject Phase I Data Analysis Task (Vol. I)-Regional 

geologic model data documentation package: ITLV/10972-81, 407 p. 

Jachens, R.C., and Moring, D.R., 1990, Maps of thickness of Cenozoic deposits and the isostatic residual 

gravity over basement for Nevada: U.S. Geological Survey Open-File Report 90-404, scale 

1:1,000,000. 

52 
Johnston, R.H., 1968, U.S. Geological Survey tracer study, Amargosa Desert, Nye County, Nevada—Part 

I, Exploratory drilling, tracer well construction and testing, and preliminary findings: U.S. Geological 

Survey Open-File Report 474-098, 64 p. 

Laczniak, R.J., Cole, J.C., Sawyer, D.A., and Trudeau, D.A., 1996, Summary of hydrogeologic controls on 

ground-water flow at the Nevada Test Site, Nye County, Nevada: U.S. Geological Survey WaterResources Investigations Report 96-4109, 59 p. 

Longwell, C.R., Pampeyan, E.H., Bowyer, Ben, and Roberts, R.J., 1965, Geology and mineral deposits of 

Clark County, Nevada: Nevada Bureau of Mines and Geology Bulletin 62, 218 p. 

Luckey, R.R., Tucci, Patrick, Faunt, C.C., Ervin, E.M., Steinkampf, W.C., D’Agnese, F.A., and Patterson, 

G.L., 1996, Status of understanding of the saturated-zone ground-water flow system at Yucca 

Mountain, Nevada as of 1995: U.S. Geological Survey Water-Resources Investigations Report 96– 

4077, 71 p. 

Maldonado, Florian, 1990, Structural geology of the upper plate of the Bullfrog Hills detachment fault 

system, southern Nevada: Geological Society of America Bulletin, v. 102, p. 992-1006. 

McAllister, J.F., 1970, Geology of the Furnace Creek borate area, Death Valley, Inyo County, California: 

California Department of Conservation, Division of Mines and Geology Map Sheet 14, scale 

1:24,000, with accompanying text. 

McAllister, J.F., 1973, Geologic map and sections of the Amargosa Valley borate area—Southeast 

continuation of the Furnace Creek area, Inyo County, California: U.S. Geological Survey 

Miscellaneous Geologic Investigations Map I-782, 1 sheet, scale 1:24,000. 

McAllister, J.F., 1974, Geologic maps and sections of a strip from Pyramid Peak to the southeast end of 

the Funeral Mountains, Ryan Quadrangle, California, in Guidebook–Death Valley Region, California 

and Nevada: Shoshone, Calif., The Death Valley Publishing Company, p. 81-83. 

McKenna, L.W. and Hodges, K.V., 1990, Constraints on the kinematics and timing of late Miocene-Recent 

extension between the Panamint and Black Mountains, southeastern California, in Wernicke, B.P., 

ed., Basin and Range extensional tectonics near the latitude of Las Vegas, Nevada: Geological 

Society of America Memoir 176, p. 363-376, map scale 1:5,840. 

Monsen, S.A., Carr, M.D., Reheis, M.C., and Orkild, P.P., 1992, Geologic map of Bare Mountain, Nye 

County, Nevada; U.S. Geological Survey Miscellaneous Investigations Series Map I-2201, scale 

1:24,000. 

Morrison, R.B., 1999, Lake Tecopa — Quaternary geology of Tecopa Valley, California, a multimillion-year 

record and its relevance to the proposed nuclear-waste repository at Yucca Mountain, Nevada: in 

Wright. L.A., and Troxel, B.W., eds., Cenozoic Basins of the Death Valley Region: Geological Society 

of America Special Paper 333, p. 301-344. 

Naff, R.L., 1973, Hydrogeology of the southern part of Amargosa Desert in Nevada: Reno, Nev., 

University of Nevada at Reno M.S. thesis, 207 p. 

Niemi, N.A., Wernicke B.P., Brady R.J., and Saleeby J.B., 2001, Distribution and provenance of the middle 

Miocene Eagle Mountain Formation, and implications for regional kinematic analysis of the Basin and 

Range province: Geological Society of America Bulletin, v. 113, p. 419–442. 

53 
Oatfield, W.J., and Czarnecki, J.B., 1989, Hydrogeologic inferences from driller’s logs and from gravity 

and resistivity surveys in the Amargosa Desert, southern Nevada: U.S. Geological Survey Open-File 

Report 89-234, 296 p. 

Plume, R.W., 1989, Ground-water conditions in Las Vegas valley, Clark County, Nevada-Part 1, 

Hydrogeologic framework: U.S. Geological Survey Water-Supply Paper 2320-A, 15 p, 5 plates. 

Prave, A.R., and McMackin, M.R., 1999, Depositional framework of mid to Late Miocene strata in the 

Dumont Hills and along the margin of the Kingston Range: Tentative implications for the 

tectonostratigraphic evolution of the southern Death Valley region, in Wright, L.A., and Troxel, B. 

W., eds., Cenozoic basins of the Death Valley region: Geological Society of America Special Paper 

333, p. 259-288. 

Reynolds, M.W., 1974, Geology of the Grapevine Mountains, Death Valley, California—A summary, in 

Guidebook—Death Valley Region, California and Nevada: Shoshone, Calif., The Death Valley 

Publishing Company, p. 92-99. 

Saltus, R.W., and Jachens, R.C., 1995, Gravity and basin-depth maps of the Basin and Range Province, 

western United States: U.S. Geological Survey Geophysical Investigations Map 1012, scale 

1:250,000. 

Sawyer, D.A., Fleck, R.J., Lanphere, M.A., Warren, R.G., Broxton, D.E., and Hudson, M.R., 1994, Episodic 

caldera volcanism in the Miocene southwestern Nevada volcanic field: revised stratigraphic 

framework, 40Ar/39Ar geochronology, and implications for magmatism and extension: Geological 

Society of America Bulletin, v. 106, p.1304-1318. 

Snow, J.K., and Lux, D.R., 1999, Tectono-sequence stratigraphy of Tertiary rocks in the Cottonwood 

Mountains and northern Death Valley area, in Wright, L.A., and Troxel, B.W., eds., Cenozoic basins 

of the Death Valley region: Geological Society of America Special Paper 333, p. 17-64. 

Topping, D.J., 1993, Paleogeographic reconstruction of the Death Valley extended region, evidence from 

Miocene large rock-avalanche deposits in the Amargosa Chaos Basin, California: Geological Society 

of America Bulletin, v. 105, p. 1190-1213. 

Tschanz, C.M., and Pampeyan, E.H., 1970, Geology and Mineral deposits of Lincoln County, Nevada: 

Nevada Bureau of Mines and Geology Bulletin 73, 188 p. 

Waddell, R.K., Robison, J.H., and Blankennagel, R.K., 1984, Hydrology of Yucca Mountain and vicinity, 

Nevada- California—Investigative results through mid-1983: U.S. Geological Survey WaterResources Investigations Report 84–4267, 72 p. 

Winograd, I.J., and Thordarson, William, 1975, Hydrogeologic and hydrochemical framework, southcentral Great Basin, Nevada-California, with special reference to the Nevada Test Site: U.S. 

Geological Survey Professional Paper 712-C, 126 p. 

Wright, L.A., 1989, Overview of the role of strike–slip and normal faulting in the Neogene history of the 

region northeast of Death Valley, California–Nevada, in Ellis,M.A., ed., Late Cenozoic evolution of 

the southern Great Basin: Nevada Bureau of Mines and Geology Open–File Report 89–1, p. 1-11. 

Wright. L.A., 1999, Cenozoic basins of the central Death Valley region, eastern California, in Slate, J.L., 

ed., Proceedings of Conference on status of geologic research and mapping in Death Valley National 

54 
Park, Las Vegas, Nevada, April, 9-11, 1999: U.S. Geological Survey Open-File Report 99-153, p. 41-

46. 

Wright, L.A., and Troxel, B.W., 1984, Geology of the northern half of the Confidence Hills 15-minute 

quadrangle, Death Valley region, eastern California — the area of the Amargosa Chaos: California 

Department of Conservation, Division of Mines and Geology Map Sheet 34, 31 p, scale 1:24,000. 

Wright, L.A., and Troxel, B.W., 1993, Geologic map of the central and northern Funeral Mountains and 

adjacent areas, Death Valley region, southern California: U.S. Geological Survey Miscellaneous 

Investigations Map I-2305, scale 1:48,000. 

Wright, L.A., Greene, R.C., Cemen, Ibrahim, Johnson, F.C., and Prave, A.R., 1999, Tectonostratigraphic 

development of the Miocene-Pliocene Furnace Creek Basin and related features, Death Valley region, 

California: in Wright. L.A., and Troxel, B.W., eds., Cenozoic Basins of the Death Valley Region: 

Geological Society of America Special Paper 333, p. 87-114. 

Wright, L.A., Thompson, R.A., Troxel, B.W., Pavlis, T.L., DeWitt, E., Otton, J.K., Ellis, M.A., Miller, M.G., 

and Serpa, L.F., 1991, Cenozoic magmatic and tectonic evolution of the east-central Death Valley 

region, California, in Walawender, M.J., and Hanan, B.B., eds., Geological excursions in southern 

California and Mexico: Geological Society of America, Geological Society of America Annual Meeting 

Guidebook 1991, p. 93-127. 

Wright, L.A., Troxel, B.W., Burchfiel, B.C., Chapman, R.H., and Labotka, T.C., 1981, Geologic cross 

section from the Sierra Nevada to the Las Vegas Valley, eastern California to southern Nevada: 

Geological Society of America Map and Chart Series, MC–28M, p. 3–15, 1 plate. 

55