Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years

Geophysical Research Letters
By: , and 

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Abstract

Subaqueous carbonates from the Devils Hole caves (southwestern USA) provide a continuous Holocene to Pleistocene North American paleoclimate record. The accuracy of this record relies on two assumptions: That carbonates precipitated close to isotope equilibrium and that groundwater temperature did not change significantly in the last 570 thousand years. Here, we investigate these assumptions using dual clumped isotope thermometry. This method relies on simultaneous analyses of carbonate 47 and 48 values and provides information on the existence and extent of kinetic isotope fractionation. Our results confirm the hypothesis that calcite precipitation occurred close to oxygen and clumped isotope equilibrium during the last half million years in Devils Hole. In addition, we provide evidence that aquifer temperatures varied by less than ±1°C during this interval. Thus, the Devils Hole calcite δ18O time series exclusively represents changes in groundwater δ18O values.

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Publication type Article
Publication Subtype Journal Article
Title Devils Hole calcite was precipitated at ±1°C stable aquifer temperatures during the last half million years
Series title Geophysical Research Letters
DOI 10.1029/2021GL093257
Volume 48
Issue 11
Year Published 2021
Language English
Publisher American Geophysical Union
Contributing office(s) WMA - Laboratory & Analytical Services Division
Description e2021GL093257, 10 p.
Country United States
State Nevada
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