Optical dating of Chinese loess using sand-sized quartz: Establishing a time frame for Late Pleistocene climate changes in the western part of the Chinese Loess Plateau
Optical dating of Chinese loess using sand-sized quartz: Establishing a time frame for Late Pleistocene climate changes in the western part of the Chinese Loess Plateau
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DOI：
10.1016/j.quageo.2007.05.003
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发表时间：
2008-02-01
影响因子：
2.7
通讯作者：
Van den haute, P.
中科院分区：
文献类型：
--
作者：
Buylaert, J. P.;Murray, A. S.;Van den haute, P.
中国黄土高原是第四纪地质学家的主要兴趣，因为它代表了一个重要的古气候波动的陆地档案。以往中国黄土的多等分发光测年研究主要使用多矿物细粒的热释光（TL）和红外释光（IRSL）信号;已知这些信号会受到异常衰减的影响，因此往往会产生年龄低估。本文研究了从中国西部三个黄土遗址（钟家蔡、乐都和土香岛）中提取的63 ~ 90 μ m石英颗粒的蓝光释光（BLSL）信号是否可以用来建立可靠的年代学。单等份再生剂量（SAR）程序用于等效剂量（D-e）测定，我们的测量方案的适用性通过剂量回收试验得到证实。本文研究了红外光致发光信号对由激光光致发光导出的石英D-c测量值的影响。根据这些结果，我们得出结论，在D-e值受到显著影响之前，可以接受高达10%的IRSL污染（表示为IRSL/BLSL比）。所有三个站点产量地层一致，空间高度可重复的光学年龄约50-70万年。在土香岛遗址，记录中的一个明显的间断被确定为近似20和近似30 ka之间;这在以前的研究中仍未被发现，并清楚地突出了高分辨率光学测年在中国黄土研究中的重要性。在这项工作中提出的光学年龄提供了更多的证据，幕式黄土沉积和变化的黄土堆积速率在西部的CLP。我们的研究似乎证实了光释光（OSL）测年的潜力，使用SAR程序适用于非常细的桑迪石英部分在中国黄土回到类似于40-50 ka（类似于120-150戈伊）。(C)2007爱思唯尔有限公司版权所有。
The Chinese Loess Plateau (CLP) is of major interest to Quaternary geologists because it represents an important terrestrial archive of palaeoclimatic fluctuations. Previous multiple-aliquot luminescence dating studies of Chinese loess mainly used thermoluminescence (TL) and infrared stimulated luminescence (IRSL) signals of polymineral fine-grains; these are known to be subject to anomalous fading and thus will tend to yield age underestimations. In this paper we investigate whether the blue-light stimulated luminescence (BLSL) signals from 63 to 90 mu m quartz grains extracted from three western Chinese loess sites (Zhongjiacai, Le Du and Tuxiangdao) can be used to establish a reliable chronology. The single-aliquot regenerative-dose (SAR) procedure is used for the equivalent dose (D-e) determinations and the suitability of our measurement protocol is confirmed by dose recovery tests. The influence of an IRSL signal on the quartz D-c measurements derived from BLSL has been investigated. From these results we conclude that an IRSL contamination, expressed as an IRSL/BLSL ratio, of up to 10% can be accepted before the values of D-e are significantly affected. All three sites yield stratigraphically consistent and spatially highly reproducible optical ages up to about 50-70 ka. At the Tuxiangdao site a marked hiatus in the record is identified between similar to 20 and similar to 30 ka; this remained undetected in previous studies and clearly highlights the importance of high-resolution optical dating in Chinese loess research. The optical ages presented in this work provide more evidence for episodic loess deposition and varying loess accumulation rates in the western part of the CLP. Our study seems to confirm the potential of optically stimulated luminescence (OSL) dating using the SAR procedure applied to the very fine sandy quartz fraction in Chinese loess back to similar to 40-50 ka (similar to 120-150 Gy). (C) 2007 Elsevier Ltd. All rights reserved.