Geochemical and grain-size evidence for the provenance of loess deposits in the Central Shandong Mountains region, northern China
Geochemical and grain-size evidence for the provenance of loess deposits in the Central Shandong Mountains region, northern China
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DOI：
10.1016/j.yqres.2016.01.005
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发表时间：
2016-03
影响因子：
2.3
通讯作者：
Shuzhen Peng;Q. Hao;Luo Wang;M. Ding;Wei Zhang;Yanan Wang;Zhengtang Guo
中科院分区：
文献类型：
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作者：
Shuzhen Peng;Q. Hao;Luo Wang;M. Ding;Wei Zhang;Yanan Wang;Zhengtang Guo
鲁中山区广泛分布的黄土沉积为北方半湿润季风区提供了宝贵的古气候记录。本文对鲁中黄土的全样品和两个粒度组（< 20 μ m和20-63 μm）的粒度分布和主量元素组成与黄土高原和黄河沉积物进行了对比，以确定其物源。中粗粉砂的比例很大，< 20 μ m和20-63 μm粒级的TiO 2/Al 2 O3和K2 O/Al 2 O3的相对不动主元素比值存在差异，这表明，形成鲁中山脉黄土沉积物的沉积物不是直接从中国北方沙漠吹来的，就像中国黄土的黄土沉积物一样高原相反，这表明，在冰期暴露在华北河流平原，包括黄河漫滩的沉积物，是主要的沙尘源的中部山公山的黄土。此外，鲁中山区广泛分布的近山黄土，表明中更新世以来冰期局部干旱化作用加强。
Widespread loess deposits in the Central Shandong Mountains yield valuable paleoclimatic records for this currently semi-humid monsoonal region of northern China. The grain-size distribution and major element composition for bulk samples and two grain-size fractions (< 20 and 20–63 μm) for the loess in the Central Shandong Mountains were compared with loess from the Chinese Loess Plateau and sediment from the Yellow River to help determine its provenance. The presence of a significant percentage of medium- and coarse-silt, and the difference in relatively immobile major element ratios of TiO2/Al2O3 and K2O/Al2O3 for the < 20 and 20–63 μm fractions, suggests that sediment that forms the loess deposits in the Central Shandong Mountains was not blown directly from the northern deserts of China as is the case for the loess deposits of the Chinese Loess Plateau. Rather, this suggests that sediments exposed during glacial times on the North China fluvial plain, including the floodplain of the Yellow River, were the major dust source for the loess in the Central Shangong Mountains. In addition, the wide distribution of perimontane loess in the Central Shandong Mountains region indicates the occurrence of strengthened local aridification during glacial times since the middle Pleistocene.