Ground-water flow to Death Valley, as inferred from the chemistry and geohydrology of selected springs in Death Valley National Park, California and Nevada

Death Valley lies downgradient from
adjacent valleys to the north, south, east, and west
in California and Nevada, and is the site of
substantial ground-water discharge. The sources
of the discharging waters have been discussed by
several investigators in the past and are of heightened
concern because of the potential disposal of
high-level radioactive waste at Yucca Mountain,
Nevada, and because of ground-water withdrawals
attendant to commercial mining in the
northwestern Amargosa Valley region. This report
describes high- and low-discharge springs in and
along the Amargosa Range that were sampled to
augment the level of understanding of the extent
and distribution of westward ground-water flow
through the range.
The Black Mountains do not seem to be
part of a significant path of ground-water flow
from the Amargosa region. This is attributed to
the complex lithology and geologic history of the
Black Mountains structural block and to the presence
of the intervening Furnace Creek fault zone.
The only ground-water discharge associated with
the Black Mountains where water chemistry
reflects an external source or sources is Saratoga
Spring, for which δ²H and δ¹⁸O data indicate
recharge in the Spring Mountains to the east.
The southern part of the Funeral Mountains
transmits a large volume of water through faulted
and fractured rocks of Cambrian age that lie at or
along the distal part of the northeast -oriented
Spotted Range-Mine Mountain structural zone.
Waters discharging from springs in the Furnace
Creek Ranch vicinity (Travertine and Nevares)
both compositionally and isotopically resemble
waters from the Ash Meadows spring group in the
Amargosa Desert. The Ash Meadows springs and
water in the Amargosa Valley alluvium likely are
chemically representative of ground water
entering the southern Funeral Mountains. Much
less ground water flows through the central and
northern Funeral Mountains than flows through
the southern part, as indicated by the geologic
setting and chemistry of Keane Wonder Spring.
The northern one-half of the mountains comprises
early-to-middle Proterozoic metamorphic rocks
that are the core of the Funeral Mountains anticlinorium.
The core is largely unfaulted, plunges to
the northeast and southwest, and is truncated to
some extent on the east by the shallow-dipping
Boundary Canyon fault. This structural setting
and the paucity of springs in the northern one-half
of the Funeral Mountains indicate a long traveltime
from the Amargosa region to the western
margin of the northern and central parts of the
mountains.
The Grapevine Mountains include the
highest elevations in the Amargosa Range.
Substantial precipitation and recharge above
about 2,000 meters are evinced by numerous
small springs and seeps along the east and west
margins. The local nature of the recharge is
reflected in δ²H and δ¹⁸O values and in the spring
chemistries that indicate control by Tertiary
volcanic rocks. The highest spring discharges
associated with the Grapevine Mountains are near
the north end of the mountains in the Grapevine
Ranch area. The springs in this area are similar
chemically and isotopically, except for one or two
order-of-magnitude differences in calcium,
magnesium, and strontium concentrations and a
1.2 per mil difference in δ¹³C values. These differences
can be attributed to differences in the distal
parts of the respective flow paths. The springs
also lie at the end of a northeast -oriented structural
zone in the Walker Lane Belt, and their δ²H,
δ¹³C, and δ¹⁸O values indicate a recharge area
likely to the northeast, outside of the Grapevine
Mountains.