Reports

Mass-Spectrometric 230Th-234U-238U Dating of the Devils Hole Calcite Vein

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Science  09 Oct 1992:
Vol. 258, Issue 5080, pp. 284-287
DOI: 10.1126/science.258.5080.284

Abstract

The Devils Hole calcite vein contains a long-term climatic record, but requires accurate chronologic control for its interpretation. Mass-spectrometric U-series ages for samples from core DH-11 yielded 230Th ages with precisions ranging from less than 1,000 years (2σ) for samples younger than ∼140 ka (thousands of years ago) to less than 50,000 years for the oldest samples (∼566 ka). The 234U/238U ages could be determined to a precision of ∼20,000 years for all ages. Calcite accumulated continuously from 566 ka until ∼60 ka at an average rate of 0.7 millimeter per 103 years. The precise agreement between replicte analyses and the concordance of the 230Th/238U 234U/238U ages for the oldest samples indicate that the DH-11 samples were closed systems and validate the dating technique in general.

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