Applicability of OSL Dating to Fine-Grained Fluvial Deposits in the Mekong River Floodplain, Cambodia
Applicability of OSL Dating to Fine-Grained Fluvial Deposits in the Mekong River Floodplain, Cambodia
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DOI：
10.2478/geochr-2020-0006
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发表时间：
2020-06
期刊：
影响因子：
1.2
通讯作者：
Y. Ishii;T. Tamura;D. Collins;Bunnarin Ben
中科院分区：
文献类型：
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作者：
Y. Ishii;T. Tamura;D. Collins;Bunnarin Ben
对细粒度（4-11 μm）河流沉积物进行光学激发发光（OSL）测年的研究很少，但这对于约束泥质冲积平原的演化至关重要。本研究基于一个非常年轻的（比细粒石英OSL年龄估计早200年），研究了OSL定年对柬埔寨湄公河细粒沉积物的适用性。细粒石英OSL的年龄与单粒石英OSL的最小年龄一致。这些结果得到了在现代细粒洪泛平原沉积物中测量到的一般较小的残留剂量（<0.1 Gy）的支持。这表明湄公河（柬埔寨）的细粒沉积物在沉积时被充分漂白，可以产生可靠的石英OSL年龄，以建立河漫滩的年表。细粒石英的充分白化部分是由于较长的输送距离，也可能发生在其他大型水系中。
Abstract Optically stimulated luminescence (OSL) dating of fine-grained (4–11 μm) fluvial sediments is rarely attempted but is crucial for constraining the evolution of mud-dominated floodplains. This study investigated the applicability of OSL dating to fine-grained deposits in the Mekong River, Cambodia based on a very young (200 years older than the fine-grained quartz OSL age estimates. Ages of fine-grained quartz OSL are concordant with the minimum ages obtained from the single-grain quartz OSL. These results are supported by the generally small residual doses (<0.1 Gy) measured in modern fine-grained flood-plain deposits. This indicates that fine-grained sediments in the Mekong River (Cambodia) are sufficiently bleached at deposition and can yield reliable quartz OSL ages for establishing the chronology of the floodplain. The sufficient bleaching of fine-grained quartz partly results from the long transport distance and may also occur in other large river systems.