K. R. Simmons Barney J. Szabo I.J. Winograd J.M. Landwehr A.C. Riggs R.J. Hoffman K.R. Ludwig 1992 <p><span>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&nbsp;</span>²³⁰<span>Th 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&nbsp;</span>²³⁴<span>U/</span>²³⁸<span>U 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 10</span>³<span>&nbsp;years. The precise agreement between replicate analyses and the concordance of the&nbsp;</span>²³⁰<span>Th/</span>²³⁸<span>U and&nbsp;</span>²³⁴<span>U/</span>²³⁸<span>U ages for the oldest samples indicate that the DH-11 samples were closed systems and validate the dating technique in general.</span></p> application/pdf 10.1126/science.258.5080.284 en American Association for the Advancement of Science Mass-spectrometric 230Th-234U-238U dating of the Devils Hole calcite vein article