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WATER-RESOURCES INVESTIGATIONS REPORT 96-4109 Water levels, underground tests, and water-bearing units in Pahute Mesa—PLATE 4 OF 4 U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the Laczniak and others, 1996, Summary of hydrogeologic controls U.S. GEOLOGICAL SURVEY U.S. DEPARTMENT OF ENERGY on ground-water flow at the Nevada Test Site, Nye County, Nevada 116°22'30" 540 000 116°30' 560 000 580 000 600 000 620 000

KAWICH RANGE EXPLANATION 116°30' 116°22'30"

Timber Mountain GroupÐTuff

BELTED RANGE

Paintbrush GroupÐWelded tuff and lava °

37 22'30" l

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Calico Hills FormationÐLava l

l Saucer

l GROUSE CANYON

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CALDERA l Mesa l

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Intracaldera Bullfrog Tuff of Crater Flat GroupÐTuff l l

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MOUNTAIN l

CALDERA l l

BLACK l

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Deadhorse Flat Formation of Belted Range GroupÐLava l

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l AREA 20 l

Fault—Approximate trace at surface l

l CALDERA A' 960 000 l 37°15' l 960 000 l l l AA' l l

Line of section—Symbol indicates control point l l l

l NEVADA TEST SITE

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l SILENT

Site of underground testÐSymbol and label identify emplacement l l CANYON

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hole in which test was detonated. Symbol size approximates estimated l CALDERA

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diameter of cavity and fracture zone generated by detonation. Number, l

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if given, is measured water-level altitude, in feet above sea level. (See l l 37 22'30 l 37 22'30 l

TIMBER MOUNTAIN l

table 5 for additional information on tests) CALDERA COMPLEX l l

Gold Flat l

U-19v Detonation more than 350 feet below water table. Yield generally l l l

greater than 150 kilotons 37°07'30" l

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U-19av Detonation between 150 feet above and 350 feet below water table. l

l Yield generally less than 150 kilotons l

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l l U-19ae Detonation more than 150 feet above water table. Yield less than 150 l

4,495 kilotons

l GROUSE CANYON U-20 Well or test holeÐLabel identifies well or hole. Number, if given, is l

Water Well CALDERA U-19u SILENT CANYON

measured water-level altitude, in feet above sea level. (See table 5 for FAULT

4,440 l additional information on wells and test holes) l U-19d 2 CALDERA COMPLEX

Pahute Mesa Ex. 2 4,684 U-19ak

4,734 l U-19d l

l U-20u l

U-20p UE-19h

4,668

UE-20p l

4,669 l

U-19n ESTUARY l

l l

940 000 U-19L

940 000 l

l EAST U-19ai l

4,688

l l FAULT l a l ic w

l U-19b

a l l r UE-20e 1 l g U-20ar 4,471 po

o U-20e U-19g UE-19b 1

t U-20ar 1/Inst. 4,685 l l 4,463 4,670

l 20 4,478

ea UE-19gS l l r A U-20aa 4,674

l in U-19am

g U-19aj l

U-20m ar l m

4,633 al FAULT U-19zS

l r U-20aj U-20g T UE-19e/Inst. FAULT

FAULT tu L U-19an 4,453 l l U 4,702 uc UE-19z/Inst. tr U-20an A U-19ax HANDLEY s 4,471 F 4,689 0 O

l 2 U-20i R

l a U-19e U-19ba

re D l

N 4,849

A GREELEY 4,698 l E

l M l U-20z L PURSE U-20ad A U-19t

BLACK l

l l

MOUNTAIN U-20aw l U-20af U-19q U-20L 4,499 U-19ac

U-20v Pahute Mesa Ex. 1 CALDERA l U-19ar l U-20k 4,459 4,587 920 000 WEST l 920 000 WEST BOXCAR FAULT U-19yS UE-20h U-19ay

l l 4,452 4,584 l U-20f U-20ab U-19aS U-19bg UE-20f 4,455

l 4,162 4,569 U-19bg 1 U-19ad l l U-20aL 4,575 UE-19c Water Well

l BOXCAR FAULT U-20am 4,697

4,451 FAULT l WEST WEST l U-20aq U-19c l U-20ai FAULT

U-20bc 4,451 U-20ap

l l 4,275 U-20bd U-20ay 4,448 l 4,465

U-20ah GREELEY

l U-20ae U-20b 4,444 l U-19av U-19p BUTEO U-19ab 2/Inst. l 4,490

U-19au 4,915 l U-19ab U-20bb 1 U-20 Water Well 4,458 U-19i EAST 4,904 l 37°15' 4,202 U-20d 4,440 37°15'

l UE-19i

U-20at U-20ak U-20ac U-19v PS 1D l 4,581 U-20at 1/Inst. 4,193 UE-20d 4,545 l 4,214 U-20bb 4,178 U-20bf 4,436 U-20a 2 Water Well U-19v l

U-20t 4,408 l U-20n U-20a 1 UE-20n 1 U-19af l

Pahute Mesa Ex 3 WEST PURSE FAULT 4,327 U-19ae 4,366 l U-20ao U-20bg 4,495 4,322 4,438

UE-20av U-19x l l U-20ax U-20av 4,330 4,567 U-20c 4,362 4,389 UE-20c U-20az U-19az l

4,184 4,157 4,412 U-19aa l U-19aq 4,673 UE-19w 1 l l l 4,690 U-20be U-19f

4,278 l l

900 000 UE-19fS FAULT U-20ag 4,429 l 900 000

U-20y l

l 4,190 U-20as l

4,214 l

l l

l ALMENDRO

l l

l n l l o y

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C l

l SCRUGHAM PEAK FAULT

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A l

y l t l

s l

i h l

l l

l l l

l l

SPLIT RIDGE FAULT o

F l l l l NELLIS AIR FORCE BASE RANGE

t s l l a E Area 20 Area 19

880 000

l l Water Well 8 880 000

NEVADA TEST SITE Area 18 4,619 l

l l

l PLE l M X A O

T IN A C l UN CALDER

TIMB O ER M l

l W l OASIS VALLEY SUBBASIN a s h e t c k F

o o

R r l UE-18r t y 4,173 m i l e

W a s l h ALKALI FLAT-FURNACE CREEK RANCH SUBBASIN UE-18t 4,285 37°07'30 37°07'30 540 000 116°30' 560 000 580 000 116°22'30" 600 000 620 000 Base from U.S. Geological Survey digital data, 1:100,000, 1981; Universal Transverse Geology by D.A. Sawyer, 1991 Mercator projection, Zone 11. Shaded-relief base from 1:100,000-scale Digital Elevation MILES 1 0 1 2 34 Model; sun illumination from northwest at 30 degrees above horizon 100,000-foot grid based on Nevada State Plane coordinate system, central zone 1120 345678 KILOMETERS

A. Geologic Section

A A' EXPLANATION

Timber Mountain caldera complex Silent Canyon caldera complex Units on geologic section—Units are defined in terms of stratigraphy and geochronology

Area 20 caldera Alluvium Bullfrog Tuff of Crater Flat Group Grouse Canyon caldera

Thirsty Canyon Group Dead Horse Flat Formation of Belted Range Group

FEET FEET Kawich Kawich 8,000 Range 8,000 U-19d2U-19uU-19ak WestU-20am GreeleyU-20ab fault Pahute Mesa Ex.1 U-19amUE-19gS Estuary fault Valley Grouse Canyon Tuff of Belted Range Group West BoxcarEast fault Boxcar fault U-20bU-20ay Buteo faultU-20bd East Greeley fault Timber Mountain Group U-20y U-20c

Paintbrush Group Volcanics of Big Dome

SEA LEVEL SEA LEVEL Older Volcanics Calico Hills Formation

-8,000 -8,000 Units on hydrogeologic section—Units are defined by their physical properties that depend chiefly on NO VERTICAL EXAGGERATION mode of eruption, cooling history, and alteration. Units are delineated only beneath water table

Welded-tuff aquifer B. Hydrogeologic Section A A' Lava-flow aquifer Area of downward flow Tuff-confining unit Kawich Range FEET Nellis Nevada FEET Range Test 8,000 Site 8,000

West Greeley fault East Greeley Estuary fault U-19d2 Pahute Mesa Ex.1 Contact—Dashed where uncertain or inferred. Short dashed line on hydrogeologic section shows geologic contacts West BoxcarEast fault Boxcar fault Buteo fault fault Kawich Valley in unsaturated rock. Dotted line on hydrogeologic section shows lithologic contact within geologic unit

Water table Fault

Water table

SEA LEVEL SEA LEVEL

Recharge zone—Size of arrow is proportional to inferred amount of local recharge

General direction of ground-water flow—Size of arrow indicates relative volume of ground-water flow. Multiple arrows at a location indicate uncertain or multiple flow directions

Drillhole—Projected into section

-8,000 -8,000 VERTICAL EXAGGERATION X2 Drillhole—Falls on section

0 12 34 5 MILES

0 12 34 5 KILOMETERS

MAP AND SECTIONS SHOWING WATER LEVELS, UNDERGROUND TESTS, AND PRINCIPAL WATER-BEARING UNITS IN UPPER 2,000 FEET OF SATURATED ROCK IN PAHUTE MESA AREA, SOUTHERN NEVADA by Randell J. Laczniak, James C. Cole, David A. Sawyer, and Douglas A. Trudeau