U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3021

February 2012

Devils Hole, Nevada—A Primer

This fact sheet summarizes the multifaceted research of the U.S. Geological Survey—published in diverse outlets—that focuses on 

the subaqueous cavern Devils Hole in Nevada.

What is Devils Hole?

Devils Hole is a subaqueous cavern in south-central Nevada within 

a geographically detached unit of Death Valley National Park (fig. 1). The 

cavern is tectonic in origin and has developed in Cambrian carbonate rocks 

bordering the Ash Meadows oasis (Carr, 1988). The open fault zone comprising the cave extends to a depth of at least 130 meters below the water table, 

which is about 15 meters below land surface (Riggs and others, 1994). The 

primary source of groundwater flowing through Devils Hole, and discharging from the major springs within the oasis, is precipitation on the Spring 

Mountains to the east of the cavern. The Spring Mountains are the highest 

mountain range in southern Nevada (altitude 3,630 meters) (Winograd and 

Thordarson, 1975; Winograd and others, 1998).

Figure 1. Index map of south-central Great Basin showing the locations of Devils 

Hole, significant springs, and the major mountains, which are shaded as follows: 

heavy shading denotes altitudes of 2,400 to 3,600 meters; light shading denotes 

altitudes of 1,800 to 2,400 meters; and ridges less than 1,800 meters are designated 

by name only.

Why is Devils Hole of interest to paleoclimatologists?

The importance of Devils Hole to paleoclimatologists is twofold. Below 

the water table, the near-vertical walls of Devils Hole are coated with up 

to 40 centimeters of vein calcite that precipitated from groundwater moving through the cavern (fig. 2). The calcite can be accurately and precisely 

dated with radiometric methods, such that the depth-varying sequences of 

oxygen and carbon stable isotopes in the calcite provide a record of climatic 

variations spanning more than 500,000 years (Winograd and others, 1988, 

1992, 2006). Additionally, subhorizontal cave deposits, called folia, record 

variations of the water table during the past 120,000 years (Szabo and others, 

1994).

Figure 2. Photograph taken just below the water table (at top of photo) in 

Brown’s Room, a remote portion of the Devils Hole cavern. Vein calcite coats the 

walls of the open fault zone that comprises Devils Hole. The rippling horizontal 

deposits called folia (in the upper fifth of the photo) mark paleo-water-table levels 

as much as a meter below the modern water level. (Photograph taken in 1986 by 

Ray Hoffman, USGS, retired.)

How was the isotopic record from the Devils Hole vein calcite dated?

Since 1992, vein calcite samples have been uraniumseries dated using thermal ionization mass spectrometric 

(TIMS) methodology (Ludwig and others, 1992). In 1997, the 

Devils Hole thorium-230 ages were independently confirmed 

by non-U.S. Geological Survey (USGS) investigators using 

protactinium-231 (Edwards and others, 1997).
What paleoclimate phenomena are recorded by the Devils Hole stable isotopic time series? 

The Devils Hole oxygen-18 (δ18O) time series (fig. 3) is 

primarily a proxy indicator of paleotemperatures. Unlike oxygen isotopes in deep-sea cores, it is not a record of past global 

ice accumulation in terrestrial systems. Rather, the time series 

appears to correspond, both in timing and relative magnitude, 

to variations in paleo-sea-surface temperature (SST) recorded 

in Pacific Ocean sediments off the west coast of North America, 

from Oregon to California, and as far south as the equatorial 

eastern Pacific (fig. 4) (Winograd and others, 1996, 1997, 2006; 

Lea and others, 2000; Herbert and others, 2001; Winograd, 

2002). The Devils Hole δ18O record is also highly correlated 

with major variations in paleotemperatures recorded in the 

Vostok ice core from the East Antarctic Plateau (Landwehr and 

Winograd, 2001; Landwehr, 2002). The Devils Hole carbon-13 

(δ13C) time series is thought to reflect changes in global variations in the ratio of stable carbon isotopes of atmospheric 

carbon dioxide (CO2) and (or) changes in the density of vegetation in the groundwater-recharge areas tributary to Devils Hole 

(Coplen and others, 1994).

Figure 3 (top right). The Devils Hole δ18O time series from 4,500 to 

567,700 years before present, with data as given in Landwehr and 

others (2011).

Figure 4 (right). The Devils Hole δ18O (in blue) and sea-surface 

temperature (in red) time series from marine cores TR163-19 

retrieved in the east equatorial Pacific at 2°N and 91°W (Lea and 

others, 2000) and ODP1020 retrieved off the Oregon-California 

border at 41°N and 126°W (Herbert and others, 2001). The linear 

correlation coefficient “r” between records is shown for the period 

from 4,500 to 360,000 years before present (Winograd and others, 

2006).

Where can one find the isotopic records?

The δ18O and δ13C time series from ~560,000 to 60,000 

years before present are provided in USGS Open-File Report 

97–792 [http://pubs.usgs.gov/of/1997/ofr97-792/] (Landwehr and others, 1997). The δ18O record for Devils Hole was 

extended into the mid-Holocene (up to ~4,500 years before 

present) and is provided in USGS Open-File Report 2011–1082 

[http://pubs.usgs.gov/of/2011/1082/] (Landwehr and others, 

2011).

What contributions has Devils Hole research made to the fields of paleoclimatology, paleohydrology, 

and geochemistry?

Publication of the half-million-year-long Devils Hole δ18O 

time series in 1992 initiated a decades-long discussion regarding the capability of the Milankovitch hypothesis (also referred 

to as orbital or astronomical theory) to predict the onset and 

duration of Pleistocene ice ages, a discussion that continues to 

this day (Wunsch, 2004; Henderson and others, 2006; Lourens 

and others, 2010). The radiometrically dated Devils Hole time 

series indicates an atmospheric warming beginning more than 

10,000 years earlier than the timing of the penultimate major 

deglaciation (also referred to as Termination II) as predicted on 
the basis of the Milankovitch hypothesis. This has been considered to be a direct challenge to the validity of orbital theory 

(Broecker, 1992; Karner and Muller, 2000). This challenge was 

dismissed by some on the grounds that if the question of early 

warming was ignored, the Devils Hole records might be interpreted as supporting the Milankovitch hypothesis (Emiliani, 

1993; Imbrie and others, 1993) but contradicted by others who 

claimed that early warming, though real, reflected only regional, 

not global, climate (Herbert and others, 2001). However, the 

original challenge posed by the early warming recorded in the 

Devils Hole δ18O time series continues: it has been reinforced 

by a variety of studies, not only of interhemispheric paleo-SST 

warming, but also of sea-level high stands (a direct proxy for 

global ice volume conditions) that have been directly dated as 

occurring thousands of years prior to orbitally predicted global 

deglaciations (Winograd and Landwehr, 1993; Landwehr and 

others, 1994; Henderson and Slowey, 2000; Henderson and 

others, 2001, 2006; Gallup and others, 2002; Muhs and others, 

2002; Winograd, 2002; Winograd and others, 2006).

Prior to publication of the Devils Hole δ18O time series, 

the duration of Pleistocene interglacial intervals was thought to 

be on the order of 12,000 years, as determined from orbitally 

tuned chronologies based on marine sediment records (Imbrie 

and others, 1984). However, an examination of the Devils Hole 

record published in 1997 revealed that the warmest portion 

alone of the past four interglaciations lasted on the order of 

10,000 to 15,000 years, whereas the entire duration of the warm 

intervals (interglacials) persisted in excess of 20,000 years, a 

finding supported by both Antarctic ice core data and sea level 

data (Winograd and others, 1997; Muhs and others, 2002). An 

additional continuing challenge to the Milankovitch hypothesis 

has been the occurrence of a high-intensity and long-duration 

interglacial from ~420,000 to ~395,000 years before present at 

a time of minimal variation in insolation, as recorded not only 

in marine isotopic records but also in the Devils Hole record 

(Winograd and others, 1992). The high correlation between the 

Devils Hole record and the ice core record at Vostok on the East 

Antarctic Plateau indicates a consistent interhemispheric timing 

of Pleistocene ice ages, which also is not consistent with the 

Milankovitch hypothesis (Landwehr and Winograd, 2001).

More recent work has corroborated these insights derived 

from Devils Hole, and it is widely acknowledged today that 

astronomical forcing alone cannot explain the duration, intensity, or diversity of the past four interglacials. More independently dated proxy records from both hemispheres would be 

required to achieve such an understanding (Tzedakis and others, 

2009). In addition, it is now widely acknowledged that variations in atmospheric greenhouse gases, notably CO2

, have 

played a major role in the glacial-interglacial climatic shifts of 

the Pleistocene, though major questions persist regarding the 

origin of the “ice ages” (Raymo and Huybers, 2008).

In addition to the near-vertical vein calcites that precipitated from groundwater below the water table and today line the 

walls of the steeply dipping open fault, Devils Hole cave also 

contains subhorizontal wall deposits, called folia, that mark the 

stands of the paleo-water table in the cavern (fig. 2) (Szabo and 

others, 1994; Kolesar and Riggs, 2004). The folia are porous 

deposits that owe their origin to outgassing at the water table 

of CO2 from the slightly supersaturated groundwater flowing 

through Devils Hole (Plummer and others, 2000). In Brown’s 

Room, a remote portion of Devils Hole cave, the folia were 

sampled up to about 9 meters above the modern water table. 

The folia visible in the upper fifth of figure 2 indicate that the 

water table was once about a meter lower than its modern level. 

Uranium-series dating of these folia has enabled the development of a 120,000-year hydrograph of water-table fluctuation in 

the cavern, which indicates a prominent decline during the past 

20,000 years (Szabo and others, 1994).

An unexpected consequence of the ability to carry out 

precise uranium-series dating of the Devils Hole cave calcite 

has been a renewed interest in other cave carbonate deposits, 

notably speleothems and flowstones (Kolesar, 2004), as archives 

of Quaternary paleoclimate. Speleothems now comprise a major 

archive of continental paleoclimatic data (Ludwig and others, 

1992; Quade, 2004; Lachniet, 2009).

A comparison of the δ18O measured in the vein calcite relative to that in Devils Hole groundwater has led to a new and significantly different estimate of the oxygen isotopic fractionation 

between calcite and water in a natural (non-laboratory) environment. This important contribution to aqueous geochemistry 

was possible because the physical and chemical constancy of 

environmental conditions at Devils Hole at depths greater than 

several meters below the water table—a constancy believed to 

have prevailed for at least 10 millennia—permits measurement 

of this fractionation in an environment at or near thermodynamic equilibrium (Coplen, 2007). Additionally, the high purity 

of the dense vein calcite allowed the development and testing of 

a new method with which to determine the δ13C and δ18O isotopic composition of CaCO3

 using smaller mass than previously 

possible (Revesz and Landwehr, 2002).

What does Devils Hole reveal about how long we can expect the present interglaciation to last?

No one knows for sure how long the present interglacial 

will last. Any estimate depends on several factors: the paleoclimatic archive and proxy record(s) utilized; the degree to which 

these records reflect global conditions; the theory invoked; and 

current potential climatic influences, such as anthropogenically 

generated greenhouse gases. The Devils Hole δ18O record indicates that the last four interglaciations each lasted over ~20,000 

years, with the warmest portion being a relatively stable period 

of 10,000 to 15,000 years duration (Winograd and others, 1997). 

The most recent portion of the Devils Hole record suggests—as 

do SST records off California—that the warmest portion of the 

current interglaciation began by 17,000 years before present 

(Winograd and others, 2006). From these data one might infer 

that in the absence of any mitigating conditions, such as anthropogenically induced climate warming, the onset of a period of 

global cooling is imminent or even overdue on a geologic time 

scale (Ruddiman, 2007). However, some researchers have suggested that the current interglaciation might continue for tens of 

thousands of years (Berger and Loutre, 2002).
What are some practical applications of the Devils Hole findings?

In addition to providing information about the possible 

duration of our present interglacial climate (discussed above), 

research in Devils Hole has been a source of valuable information for water managers. Devils Hole cave provides hydrologists with direct access for making hydraulic measurements 

and collecting chemical samples of the regional carbonate-rock 

aquifer underlying much of south-central Nevada and which 

supplies the groundwater that is discharging within the Ash 

Meadows oasis. Meaningful estimates of the sustainable use of 

this aquifer hinge on knowing the age of the groundwater. Estimates of the groundwater age inferred from carbon-14 dating 

of dissolved inorganic carbon in the groundwater have yielded 

an age in the range of 13,000 to 25,000 years (Anderson, 

2002), whereas carbon-14 dating of dissolved organic carbon 

has yielded ages on the order of 3,000 to 7,000 years (Thomas, 

1996; Morse, 2002). However, several lines of evidence derived 

from Devils Hole indicate a groundwater age of 2,000 years 

or less (as discussed in appendix A in Winograd and others, 

2006). The evaluation of Yucca Mountain, which is about 

45 kilometers north-northwest of Devils Hole, for the geologic 

disposal of spent nuclear fuel has required estimation of past 

and future climates over time frames of hundreds of thousands 

of years. The paleoclimatologic and paleohydrologic information gleaned from Devils Hole has provided the foundation for 

such estimates (Forester and others, 1999; Sharpe, 2007; Paces 

and others, 2010).

Why is Devils Hole of interest to zoologists?

The endangered species of pupfish Cyprinodon diabolis

is endemic to Devils Hole, with a habitat dependent on stable 

groundwater-table levels (Dudley and Larson, 1976). Concern 

for the protection of this unique species’ habitat provided the 

first test of the Endangered Species Act and resulted in the 

unanimous affirmative landmark decision by the U.S. Supreme 

Court in 1976 (Cappaert v. United States, 426 U.S. 128). This 

pupfish species has been studied by zoologists for decades, 

not only because of its unusual habitat, but also because of 

speciation-process debates concerning the length of its isolation 

from other members of its genus (Riggs and Deacon, 2004). 

Estimates of the length of its isolation range from tens of thousands of years (Riggs, 1991) to perhaps hundreds of thousands 

of years (Winograd, 1991; based on data in Winograd and 

Szabo, 1988).

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A 250,000-year climate record from Great Basin vein calcite—Implications for Milankovitch theory: Science, v. 242, 

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and hydrochemical framework, south-central Great Basin, 

Nevada–California, with special reference to the Nevada 

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For more information, contact:

Jurate M. Landwehr

U.S. Geological Survey, 431 National Center

12201 Sunrise Valley Drive

Reston, VA 20192

E-mail: jmlandwe@usgs.gov

Isaac J. Winograd

U.S. Geological Survey, 432 National Center

12201 Sunrise Valley Drive

Reston, VA 20192

E-mail: ijwinogr@usgs.gov