Geologic map of the Yucca Mountain region, Nye County, Nevada

Title: Geologic map of the Yucca Mountain region, Nye County, Nevada
Abstract:: Yucca Mountain, Nye County, Nevada, has been identified as a potential site for underground storage of high-level radioactive waste. This geologic map compilation, including all of Yucca Mountain and Crater Flat, most of the Calico Hills, western Jackass Flats, Little Skull Mountain, the Striped Hills, the Skeleton Hills, and the northeastern Amargosa Desert, portrays the geologic framework for a saturated-zone hydrologic flow model of the Yucca Mountain site. Key geologic features shown on the geologic map and accompanying cross sections include: (1) exposures of Proterozoic through Devonian strata inferred to have been deformed by regional thrust faulting and folding, in the Skeleton Hills, Striped Hills, and Amargosa Desert near Big Dune; (2) folded and thrust-faulted Devonian and Mississippian strata, unconformably overlain by Miocene tuffs and lavas and cut by complex Neogene fault patterns, in the Calico Hills; (3) the Claim Canyon caldera, a segment of which is exposed north of Yucca Mountain and Crater Flat; (4) thick densely welded to nonwelded ash-flow sheets of the Miocene southwest Nevada volcanic field exposed in normal-fault-bounded blocks at Yucca Mountain; (5) upper Tertiary and Quaternary basaltic cinder cones and lava flows in Crater Flat and at southernmost Yucca Mountain; and (6) broad basins covered by Quaternary and upper Tertiary surficial deposits in Jackass Flats, Crater Flat, and the northeastern Amargosa Desert, beneath which Neogene normal and strike-slip faults are inferred to be present on the basis of geophysical data and geologic map patterns.
A regional thrust belt of late Paleozoic or Mesozoic age affected all pre-Tertiary rocks in the region; main thrust faults, not exposed in the map area, are interpreted to underlie the map area in an arcuate pattern, striking north, northeast, and east. The predominant vergence of thrust faults exposed elsewhere in the region, including the Belted Range and Specter Range thrusts, was to the east, southeast, and south. The vertical to overturned strata of the Striped Hills are hypothesized to result from successive stacking of three south- vergent thrust ramps, the lowest of which is the Specter Range thrust. The CP thrust is interpreted as a north-vergent backthrust that may have been roughly contemporaneous with the Belted Range and Specter Range thrusts.
The southwest Nevada volcanic field consists predominantly of a series of silicic tuffs and lava flows ranging in age from 15 to 8 Ma. The map area is in the southwestern quadrant of the southwest Nevada volcanic field, just south of the Timber Mountain caldera complex.
The Claim Canyon caldera, exposed in the northern part of the map area, contains thick deposits of the 12.7-Ma Tiva Canyon Tuff, along with widespread megabreccia deposits of similar age, and subordinate thick exposures of other 12.8- to 12.7-Ma Paintbrush Group rocks. An irregular, blocky fault array, which affects parts of the caldera and much of the nearby area, includes several large-displacement, steeply dipping faults that strike radially to the caldera and bound south-dipping blocks of volcanic rock.
South and southeast of the Claim Canyon caldera, in the area that includes Yucca Mountain, the Neogene fault pattern is dominated by closely spaced, north-northwest- to north- northeast-striking normal faults that lie within a north- trending graben. This 20- to 25-km-wide graben includes Crater Flat, Yucca Mountain, and Fortymile Wash, and is bounded on the east by the "gravity fault" and on the west by the Bare Mountain fault. Both of these faults separate Proterozoic and Paleozoic sedimentary rocks in their footwalls from Miocene volcanic rocks in their hanging walls.
Stratigraphic and structural relations at Yucca Mountain demonstrate that block-bounding faults were active before and during eruption of the 12.8- to 12.7-Ma Paintbrush Group, and significant motion on these faults continued until after the 11.6-Ma Rainier Mesa Tuff was deposited. North of Crater Flat, in and near the Claim Canyon caldera, most of the tilting of the volcanic section predated the 11.6-Ma Rainier Mesa Tuff. In contrast, geologic relations in central and southern Yucca Mountain indicate that much of the stratal tilting there occurred after 11.6 Ma, probably synchronous with the main pulse of vertical-axis rotation that occurred between 11.6 and 11.45 Ma.
Beneath the broad basins, such as Crater Flat, Jackass Flats, and the Amargosa Desert, faults are inferred from geophysical data. Geologic and geophysical data imply the presence of the large-offset, east-west-striking Highway 95 fault beneath surficial deposits along the northeast margin of the Amargosa Desert, directly south of Yucca Mountain and Crater Flat. The Highway 95 fault is interpreted to be downthrown to the north, with a component of dextral displacement. It juxtaposes a block of Paleozoic carbonate rock overlain by a minimal thickness of Tertiary rocks (to the south) against the Miocene volcanic section of Yucca Mountain (to the north).
Alluvial geomorphic surfaces compose the bulk of Quaternary surficial units in the Yucca Mountain region. Deposits associated with these surfaces include alluvium, colluvium, and minor eolian and debris-flow sediments. Photogeologic and field studies locally have identified subtle fault scarps that offset these surfaces, and other evidence of Quaternary fault activity.
Supplemental_Information:: Topographic base from these U.S. Geological Survey 1:24,000- scale digital line graph (DLG) quadrangles: East of Beatty Mountain, Topopah Spring NW, Topopah Spring, Jackass Flats, Striped Hills, Crater Flat, Busted Butte, Big Dune, Amargosa Valley, South of Amargosa Valley, Ashton, Beatty Mountain, Carrara Canyon, Lees Camp, Leeland, Skeleton Hills. 50,000-ft grid based on Nevada State Plane coordinates. Contour interval is 40 ft. DLG's were clipped to fit into the area of interest.
Township and Range boundaries from U.S. Geological Survey 1: 100,000-scale Digital Line Graph data for the Beatty quadrangle.
Roads are from the DOE/OCRWM/YMSCO database, coverage ROADNYES, reference G97558, based on U.S. Census Bureau, 1:100,000-scale TIGER data for Nye County, Nevada.

Value	Definition
CZw	Wood Canyon Formation
Cb	Bonanza King Formation
Cc	Carrara Formation
Cn	Nopah Formation
Cz	Zabriskie Quartzite
DSd	Dolomite
Dc	Dolomite limestone and sandy dolomite
MDs	Clastic sedimentary rocks (includes Eleana)
Mc	Chainman Shale
Ou	Sedimentary rocks, undivided (Ely Sprs. Eureka Pogonip)
Qa	Alluvium (Holocene)
Qam	Alluvium (late and middle Pleistocene)
Qao	Older alluvium (middle and early Pleistocene)
Qay	Younger alluvium (Holocene and late Pleistocene)
Qay/Qam	mantle of Qay over Qam
Qay/Qem	mantle of Qay over Qem
Qbo	Older Quaternary basalt
Qby	Younger Quaternary basalt
Qe	Eolian deposits (Holocene to middle Pleistocene)
Qem	Eolian-colluvial ramp deposits (Holocene-middle Pleis.)
Qem/Qao	mantle of Qem over Qao
Qeo	Older eolian sand (middle to early Pleistocene)
Qey	Eolian sand and fragments (Holocene and late Pleistocene)
Qey/Qam	mantle of Qey over Qam
Qey/Qeo	mantle of Qey over Qeo
Qsd	Spring deposits (Holocene to middle Pleistocene)
Tac	Calico Hills Formation
Tbo	Older Tertiary basalts (Miocene)
Tby	Younger Tertiary basalt of Crater Flat (Pliocene)
Tcb	Bullfrog Tuff
Tcp	Prow Pass Tuff
Tcr	Rhyolite of Prospector Pass
Tcs	Pre-Bullfrog Tuff bedded tuff
Tct	Tram Tuff
Tfb	Beatty Wash Formation
Tfd	Lavas of Dome Mountain
Tfs	Rhyolite of Shoshone Mountain
Tgc	Conglomerates, fanglomerates, and rock-avalanche breccia
Ti	Intrusions (Miocene)
Tma	Ammonia Tanks Tuff
Tmb	Rhyolite of Waterpipe Butte
Tmp	Rhyolite of Pinnacles Ridge
Tmr	Rainier Mesa Tuff
Tmw	Rhyolite of Windy Wash
Tpbt	Bedded tuff (Paintbrush Gp.)
Tpc	Tiva Canyon Tuff
Tpcy	Tuff of Pinyon Pass
Tpd	Rhyolite of Delirium Canyon
Tpk	Rhyolite of Comb Peak
Tpp	Pah Canyon Tuff
Tpr	Rhyolite lavas, undivided (Paintbrush Gp.)
Tpt	Topopah Spring Tuff
Tpv	Rhyolite of Vent Pass
Tpx	Paintbrush Group tuffs, undivided (flt zn: tectonically mixed)
Tpy	Yucca Mountain Tuff
Trx	Rock-avalanche breccia of southern Crater Flat (Miocene)
Ts	Older sedimentary rocks, undivided (Miocene and Oligocene
Ttr	Rocket Wash Tuff of Thirsty Canyon Group (Miocene)
Tvo	Older volcanic rocks, undivided (Miocene)
Tvx	Intracaldera and caldera margin megabreccia and mesobreccia
Tvy	Younger volcanic rocks (Pliocene to Miocene)
Tw	Wahmonie Formation
Zs	Stirling Quartzite

Value

Definition

CZw

Wood Canyon Formation

Bonanza King Formation

Carrara Formation

Nopah Formation

Zabriskie Quartzite

DSd

Dolomite

Dolomite limestone and sandy dolomite

MDs

Clastic sedimentary rocks (includes Eleana)

Chainman Shale

Sedimentary rocks, undivided (Ely Sprs. Eureka Pogonip)

Alluvium (Holocene)

Qam

Alluvium (late and middle Pleistocene)

Qao

Older alluvium (middle and early Pleistocene)

Qay

Younger alluvium (Holocene and late Pleistocene)

Qay/Qam

mantle of Qay over Qam

Qay/Qem

mantle of Qay over Qem

Qbo

Older Quaternary basalt

Qby

Younger Quaternary basalt

Eolian deposits (Holocene to middle Pleistocene)

Qem

Eolian-colluvial ramp deposits (Holocene-middle Pleis.)

Qem/Qao

mantle of Qem over Qao

Qeo

Older eolian sand (middle to early Pleistocene)

Qey

Eolian sand and fragments (Holocene and late Pleistocene)

Qey/Qam

mantle of Qey over Qam

Qey/Qeo

mantle of Qey over Qeo

Qsd

Spring deposits (Holocene to middle Pleistocene)

Tac

Calico Hills Formation

Tbo

Older Tertiary basalts (Miocene)

Tby

Younger Tertiary basalt of Crater Flat (Pliocene)

Tcb

Bullfrog Tuff

Tcp

Prow Pass Tuff

Tcr

Rhyolite of Prospector Pass

Tcs

Pre-Bullfrog Tuff bedded tuff

Tct

Tram Tuff

Tfb

Beatty Wash Formation

Tfd

Lavas of Dome Mountain

Tfs

Rhyolite of Shoshone Mountain

Tgc

Conglomerates, fanglomerates, and rock-avalanche breccia

Intrusions (Miocene)

Tma

Ammonia Tanks Tuff

Tmb

Rhyolite of Waterpipe Butte

Tmp

Rhyolite of Pinnacles Ridge

Tmr

Rainier Mesa Tuff

Tmw

Rhyolite of Windy Wash

Tpbt

Bedded tuff (Paintbrush Gp.)

Tpc

Tiva Canyon Tuff

Tpcy

Tuff of Pinyon Pass

Tpd

Rhyolite of Delirium Canyon

Tpk

Rhyolite of Comb Peak

Tpp

Pah Canyon Tuff

Tpr

Rhyolite lavas, undivided (Paintbrush Gp.)

Tpt

Topopah Spring Tuff

Tpv

Rhyolite of Vent Pass

Tpx

Paintbrush Group tuffs, undivided (flt zn: tectonically mixed)

Tpy

Yucca Mountain Tuff

Trx

Rock-avalanche breccia of southern Crater Flat (Miocene)

Older sedimentary rocks, undivided (Miocene and Oligocene

Ttr

Rocket Wash Tuff of Thirsty Canyon Group (Miocene)

Tvo

Older volcanic rocks, undivided (Miocene)

Tvx

Intracaldera and caldera margin megabreccia and mesobreccia

Tvy

Younger volcanic rocks (Pliocene to Miocene)

Wahmonie Formation

Stirling Quartzite

Range of values
Minimum:	0
Maximum:	999

Range of values

Minimum:

Maximum:

999

Value	Definition
BORDER_50K_MAP	Extent of study area
CALDERA	Structural Boundary of Claim Canyon Caldera
CONTACT	Geologic contact - exposed or well constrained
CONTACT_APPROX	Geologic contact - approximately located
CONTACT_CONCEALED	Geologic contact - concealed beneath Quaternary cover or poorly exposed
CONTACT_Q	Geologic contact of Quaternary aged deposits
CROSS_SECTION_LINES	Location of cross sections A-A', B-B', C-C', and D-D'
FAULT	Fault - exposed or well constrained
FAULT_APPROX	Fault - approximately located
FAULT_INFER_GEOL	Fault - concealed and inferred beneath Quaternary cover
FAULT_INFER_GP	Fault - concealed beneath Quaternary cover and inferred from geophysical data
FAULT_PRE_TERTIARY_THRUST	Thrust fault - pre-Tertiary age, exposed or well constrained
FAULT_PRE_TERTIARY_THRUST_INFER	Thrust fault - pre-Tertiary age, concealed and inferred beneath Quaternary cover or poorly exposed
FAULT_LOW_ANGLE_NORMAL	Gently dipping normal fault
SCARP_AL	Fault scarps in Quaternary deposits
SYMBOL_CALC_DIP	Symbols displaying strike and dip of bedrock estimated using 3-point method
SYMBOL_FLT_FLD	Symbols displaying relative horizontal movement (paired arrows) on faults, teeth on reverse faults, and queries (uncertain) fault locations), and fold axes
SYMBOL_FOLIATION	Symbols displaying strike and dip of compaction foliation
SYMBOL_HORIZ_BD	Symbols displaying horizontal bedding
SYMBOL_OVRTRN_BD	Symbols displaying overturned bedding
SYMBOL_STRIKE_DIP	Symbols displaying strike and dip of bedding
SYMBOL_VERT_BED	Symbols displaying vertically dipping bedding
UNIT_LABELS	Line leaders from map unit to text describing bedrock geologic units
UNIT_LABELS_Q	Line leaders from map unit to text describing geologic units of Quaternary age

Value

Definition

BORDER_50K_MAP

Extent of study area

CALDERA

Structural Boundary of Claim Canyon Caldera

CONTACT

Geologic contact - exposed or well constrained

CONTACT_APPROX

Geologic contact - approximately located

CONTACT_CONCEALED

Geologic contact - concealed beneath Quaternary cover or poorly exposed

CONTACT_Q

Geologic contact of Quaternary aged deposits

CROSS_SECTION_LINES

Location of cross sections A-A', B-B', C-C', and D-D'

FAULT

Fault - exposed or well constrained

FAULT_APPROX

Fault - approximately located

FAULT_INFER_GEOL

Fault - concealed and inferred beneath Quaternary cover

FAULT_INFER_GP

Fault - concealed beneath Quaternary cover and inferred from geophysical data

FAULT_PRE_TERTIARY_THRUST

Thrust fault - pre-Tertiary age, exposed or well constrained

FAULT_PRE_TERTIARY_THRUST_INFER

Thrust fault - pre-Tertiary age, concealed and inferred beneath Quaternary cover or poorly exposed

FAULT_LOW_ANGLE_NORMAL

Gently dipping normal fault

SCARP_AL

Fault scarps in Quaternary deposits

SYMBOL_CALC_DIP

Symbols displaying strike and dip of bedrock estimated using 3-point method

SYMBOL_FLT_FLD

Symbols displaying relative horizontal movement (paired arrows) on faults, teeth on reverse faults, and queries (uncertain) fault locations), and fold axes

SYMBOL_FOLIATION

Symbols displaying strike and dip of compaction foliation

SYMBOL_HORIZ_BD

Symbols displaying horizontal bedding

SYMBOL_OVRTRN_BD

Symbols displaying overturned bedding

SYMBOL_STRIKE_DIP

Symbols displaying strike and dip of bedding

SYMBOL_VERT_BED

Symbols displaying vertically dipping bedding

UNIT_LABELS

Line leaders from map unit to text describing bedrock geologic units

UNIT_LABELS_Q

Line leaders from map unit to text describing geologic units of Quaternary age

COLUMN--ITEM_NAME----------WIDTH-----OUTPUT-----TYPE---#_DECIMALS 1-------FNODE#---------------4----------5---------B---------\ 5-------TNODE#---------------4----------5---------B---------\ 9-------LPOLY#---------------4----------5---------B---------\ 13------RPOLY#---------------4----------5---------B---------\ 17------LENGTH---------------8---------18---------F---------5 25------<cover>#-------------4----------5---------B---------\ 29------<cover>-ID-----------4----------5---------B---------\ For polygons these attributes are: COLUMN--ITEM_NAME----------WIDTH-----OUTPUT-----TYPE---#_DECIMALS 1-------AREA-----------------8---------18---------F---------5 9-------PERIMETER------------8---------18---------F---------5 17------<cover>#-------------4----------5---------B---------\ 21------<cover>-ID-----------4----------5---------B---------\ COVERAGE-----FEATURE-----DESCRIPTION Items/Attributes----------Values plate1-----lines-----cultural linework (roads, township and range, NTS boundary, map border and tics) ITEM: layer DESCRIPTION: ROADS_FINAL Roads in study area TOWN_RANGE Township and range boundaries SECTIONS_100K Township and range section lines NTS Nevada Test Site boundary BORDER Map border TICS_STATE_PLANE Nevada State Plane graticules TICS_LAT_LONG Latitude and longitude graticules ball_bar-----lines--------displacement symbols on faults ball_bar-----polygons-----displacement symbols on faults ITEM: ssym DESCRIPTION: 1 Number corresponding to a shadeset symbol szgeol-----polygons-------geologic units ITEMS: DESCRIPTION: MAP_UNIT Lithostratigraphic symbols UNIT_DESCRIPTION Description of lithostratigraphic symbols SSYM Number corresponding to a shadeset symbol (Values for the coverage items are presented in table format below) MAP_UNIT...UNIT_DESCRIPTION... SSYM CZw Wood Canyon Formation 694 Cb Bonanza King Formation 461 Cc Carrara Formation 601 Cn Nopah Formation 518 Cz Zabriskie Quartzite 810 DSd Dolomite 55 Dc Dolomite limestone and sandy dolomite 52 MDs Clastic sedimentary rocks (includes Eleana) 332 Mc Chainman Shale 179 Ou Sedimentary rocks, undivided (Ely Sprs. Eureka Pogonip) 238 Qa Alluvium (Holocene) 748 Qam Alluvium (late and middle Pleistocene) 705 Qao Older alluvium (middle and early Pleistocene) 501 Qay Younger alluvium (Holocene and late Pleistocene) 575 Qay/Qam mantle of Qay over Qam 705 Qay/Qem mantle of Qay over Qem 767 Qbo Older Quaternary basalt 98 Qby Younger Quaternary basalt 130 Qe Eolian deposits (Holocene to middle Pleistocene) 759 Qem Eolian-colluvial ramp deposits (Holocene-middle Pleis.) 767 Qem/Qao mantle of Qem over Qao 501 Qeo Older eolian sand (middle to early Pleistocene) 576 Qey Eolian sand and fragments (Holocene and late Pleistocene) 715 Qey/Qam mantle of Qey over Qam 705 Qey/Qeo mantle of Qey over Qeo 576 Qsd Spring deposits (Holocene to middle Pleistocene) 681 Tac Calico Hills Formation 184 Tbo Older Tertiary basalts (Miocene) 129 Tby Younger Tertiary basalt of Crater Flat (Pliocene) 372 Tcb Bullfrog Tuff 509 Tcp Prow Pass Tuff 422 Tcr Rhyolite of Prospector Pass 151 Tcs Pre-Bullfrog Tuff bedded tuff 322 Tct Tram Tuff 152 Tfb Beatty Wash Formation 632 Tfd Lavas of Dome Mountain 119 Tfs Rhyolite of Shoshone Mountain 633 Tgc Conglomerates, fanglomerates, and rock-avalanche breccia 652 Ti Intrusions (Miocene) 217 Tma Ammonia Tanks Tuff 721 Tmb Rhyolite of Waterpipe Butte 111 Tmp Rhyolite of Pinnacles Ridge 707 Tmr Rainier Mesa Tuff 124 Tmw Rhyolite of Windy Wash 905 Tpbt Bedded tuff (Paintbrush Gp.) 116 Tpc Tiva Canyon Tuff 901 Tpcy Tuff of Pinyon Pass 732 Tpd Rhyolite of Delirium Canyon 114 Tpk Rhyolite of Comb Peak 154 Tpp Pah Canyon Tuff 542 Tpr Rhyolite lavas, undivided (Paintbrush Gp.) 155 Tpt Topopah Spring Tuff 336 Tpv Rhyolite of Vent Pass 554 Tpx Paintbrush Group tuffs, undivided (flt zn: tectonically mixed) 577 Tpy Yucca Mountain Tuff 514 Trx Rock-avalanche breccia of southern Crater Flat (Miocene) 303 Ts Older sedimentary rocks, undivided (Miocene and Oligocene 387 Ttr Rocket Wash Tuff of Thirsty Canyon Group (Miocene) 555 Tvo Older volcanic rocks, undivided (Miocene) 909 Tvx Intracaldera and caldera margin megabreccia and mesobreccia 541 Tvy Younger volcanic rocks (Pliocene to Miocene) 527 Tw Wahmonie Formation 304 Zs Stirling Quartzite 494 szlines-----lines-----attributed with ITEM layer as follows: ITEM: layer DESCRIPTION: BORDER_50K_MAP Extent of study area CALDERA Structural Boundary of Claim Canyon Caldera CONTACT Geologic contact - exposed or well constrained CONTACT_APPROX Geologic contact - approximately located CONTACT_CONCEALED Geologic contact - concealed beneath Quaternary cover or poorly exposed CONTACT_Q Geologic contact of Quaternary aged deposits CROSS_SECTION_LINES Location of cross sections A-A', B-B', C-C', and D-D' FAULT Fault - exposed or well constrained FAULT_APPROX Fault - approximately located FAULT_INFER_GEOL Fault - concealed and inferred beneath Quaternary cover FAULT_INFER_GP Fault - concealed beneath Quaternary cover and inferred from geophysical data FAULT_PRE_TERTIARY_THRUST Thrust fault - pre-Tertiary age, exposed or well constrained FAULT_PRE_TERTIARY_THRUST_INFER Thrust fault - pre-Tertiary age, concealed and inferred beneath Quaternary cover or poorly exposed FAULT_LOW_ANGLE_NORMAL Gently dipping normal fault SCARP_AL Fault scarps in Quaternary deposits SYMBOL_CALC_DIP Symbols displaying strike and dip of bedrock estimated using 3-point method SYMBOL_FLT_FLD Symbols displaying relative horizontal movement (paired arrows) on faults, teeth on reverse faults, and queries (uncertain) fault locations), and fold axes SYMBOL_FOLIATION Symbols displaying strike and dip of compaction foliation SYMBOL_HORIZ_BD Symbols displaying horizontal bedding SYMBOL_OVRTRN_BD Symbols displaying overturned bedding SYMBOL_STRIKE_DIP Symbols displaying strike and dip of bedding SYMBOL_VERT_BED Symbols displaying vertically dipping bedding UNIT_LABELS Line leaders from map unit to text describing bedrock geologic units UNIT_LABELS_Q Line leaders from map unit to text describing geologic units of Quaternary age szlines-----annotation-----Text for geologic units, borehole and map symbol labels subclass: anno.dxf Description Level 1 geology labels 3 fault names 4 cross section trace labels 5 borehole labels 6 foliation labels 7 measured strike and dip labels 8 calculated strike and dip labels 9 overturned bedding labels 10 queries symbols(?)on fault traces szlines-----points-----borehole locations ITEM: layer DESCRIPTION: BOREHOLES_1996 Location of selected bore holes in study area Topo24k_pot-----arcs-----topographic base ITEMS: DESCRIPTION: elev_ft elevation of line index200 1 if line is a 200 ft index contour, otherwise 0

Data format:	Geologic units and structural features in format ArcInfo export (version 8.0.2) Size: 7 megabytes
Network links:	<http://pubs.usgs.gov/imap/2002/i-2755/i-2755.tar.gz> <http://pubs.usgs.gov/imap/2002/i-2755/i-2755.zip>

Data format:

Geologic units and structural features in format ArcInfo export (version 8.0.2) Size: 7 megabytes

Network links:

<http://pubs.usgs.gov/imap/2002/i-2755/i-2755.tar.gz>
<http://pubs.usgs.gov/imap/2002/i-2755/i-2755.zip>

Geologic map of the Yucca Mountain region, Nye County, Nevada

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