Insights into the provenance of the Chinese Loess Plateau from joint zircon U-Pb and garnet geochemical analysis of last glacial loess
Insights into the provenance of the Chinese Loess Plateau from joint zircon U-Pb and garnet geochemical analysis of last glacial loess
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DOI：
10.1017/qua.2017.86
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发表时间：
2018-05-01
影响因子：
2.3
通讯作者：
Lin, Zeng
中科院分区：
文献类型：
--
作者：
Fenn, Kaja;Stevens, Thomas;Lin, Zeng
中国黄土高原是世界上最大、最古老的黄土记录，保存了亚洲长期沙尘源动态的证据，但沉积物的来源存在不确定性。最近的单晶碎屑锆石 U-Pb 年龄分析在这个问题上取得了进展，但关于来源变化以及锆石数据的生成和解释的争论仍然存在。为了解决这个问题，我们分析了来自黄土高原和潜在来源的新数据集和现有数据集的不同分组。我们还介绍了利用碎屑锆石 U-Pb 测年和碎屑石榴石地球化学对北果园黄土进行首次高分辨率采样、多代理物源分析的结果。数据显示，黄土高原不同地区之间似乎存在一些小的来源差异。然而，黄土和古土壤之间的沉积物来源似乎没有变化，支持了最近的材料回收假说。然而，我们的锆石和石榴石数据表明，北果园在末次盛冰期经历了暂时的、突然的源转移，这意味着当地的尘埃源在第四纪期间变得周期性活跃。我们的结果强调，对数据进行分组以获得更大的数据集可能会导致识别误导性趋势。此外，我们建议需要采用多代理单颗粒方法来进一步了解中国黄土高原灰尘来源。
The Chinese Loess Plateau, the world's largest and oldest loess record, preserves evidence of Asia's long-term dust source dynamics, but there is uncertainty over the source of the deposits. Recent single-grain detrital zircon U-Pb age analysis has progressed this issue, but debates remain about source changes, and the generation and interpretation of zircon data. To address this, we analyze different groupings of new and existing datasets from the Loess Plateau and potential sources. We also present the results of a first high resolution sampling, multi-proxy provenance analysis of Beiguoyuan loess using U-Pb dating of detrital zircons and detrital garnet geochemistry. The data shows that some small source differences seem to exist between different areas on the Loess Plateau. However, sediment source appears to be unchanging between loess and palaeosols, supporting a recent material recycling hypothesis. Our zircon and garnet data demonstrates, however, that Beiguoyuan experienced a temporary, abrupt source shift during the last glacial maximum, implying that local dust sources became periodically active during the Quaternary. Our results highlight that grouping data to achieve bigger datasets could cause identification of misleading trends. Additionally, we suggest that multi-proxy single-grain approaches are required to gain further insight into Chinese Loess Plateau dust sources.