Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terres

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• 作者：Lewis A. Owen ; Jordon Bright ; Robert C. Finkel ; Manoj K. Jaiswal ; Darrell S. Kaufman ; Shannon Mahan ; Ulrich Radtke ; Joan S. Schneider ; Warren Sharp ; Ashok K. Singhvi ; et al.
• 刊名：Quaternary International
• 出版年：2007
• 出版时间：May 2007
• 年：2007
• 卷：166
• 期：1
• 页码：87-110
• 全文大小：2406 K

文摘

A Late Quaternary spit-shoreline complex on the northern shore of Pleistocene Lake Mojave of southeastern California, USA was studied with the goal of comparing accelerator mass spectrometry (AMS) radiocarbon, luminescence, electron spin resonance (ESR), terrestrial cosmogenic radionuclide (TCN) surface exposure, amino acid racemization (AAR) and U-series dating methods. The pattern of ages obtained by the different methods illustrates the complexity of processes acting in the lakeshore environment and highlights the utility of a multi-method approach. TCN surface exposure ages (mostly 20–30 ka) record the initial erosion of shoreline benches, whereas radiocarbon ages on shells (determined in this and previous studies) within the spit, supported by AAR data, record its construction at fluctuating lake levels from 16 to 10 ka. Luminescence ages on spit sediment (6–7 ka) and ESR ages on spit shells (4 ka) are anomalously young relative to radiocarbon ages of shells within the same deposits. The significance of the surprisingly young luminescence ages is not clear. The younger ESR ages could be a consequence of post-mortem enrichment of U in the shells. High concentrations of detrital thorium in tufa coating spit gravels inhibited the use of single-sample U-series dating. Detailed comparisons such as this provide one of the few means of assessing the accuracy of Quaternary dating techniques. More such comparisons are needed.