Open-File Report 2011–1082
INTRODUCTIONThis report presents the numeric values for the chronology of the paleoclimatically relevant mid-to-late Pleistocene record of the ratios of stable oxygen isotope (δ18O) in vein calcite from Devils Hole, Nev., which recently had been extended into the mid-Holocene. Dating was obtained using 230Th-234U-238U thermal ionization mass spectrometry. Devils Hole is a subaqueous cave of tectonic origin, which developed in the discharge zone of a regional aquifer in south-central Nevada. The primary groundwater recharge source area is the Spring Mountains, the highest mountain range in southern Nevada [altitude 3,630 meters (m)], approximately 80 kilometers to the east of the cavern. The walls of the open fault zone comprising the cave system are coated with dense vein calcite precipitated from the through-flowing groundwater. The calcite, up to 40 centimeters (cm) thick, contains a continuous record of the sequential variation of the composition of stable oxygen isotopes in the ground water over time. The vein calcite has also proven to be a suitable material for precise uranium-series dating via thermal ionization mass spectrometry utilizing the 230Th-234U-238U decay clock. Earlier work has presented data from the Devils Hole core DH–11, a 36-cm-long core of vein calcite recovered from a depth of about 30 m below the water table (about 45 m beneath the ground surface). The DH–11 core provided a continuous record of isotopic oxygen variation from 567,700 to 59,800 years before present. Recent work has extended this record into the mid-Holocene epoch. |
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Landwehr, J.M., Sharp, W.D., Coplen, T.B., Ludwig, K.R., and Winograd, I.J., 2011, The chronology for the δ18O record from Devils Hole, Nevada, extended into the mid-Holocene: U.S. Geological Survey Open-File Report 2011–1082, 5 p. (Available only at https://pubs.usgs.gov/of/2011/1082/.)
Abstract
Introduction
Description of Analyzed Material
Devils Hole δ18O Chronology
Summary
References Cited