Provenance of Clay Minerals in the Amami Sankaku Basin and Their Paleoclimate Implications Since Late Pleistocene |
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| Authors: | Liu Huahua Jiang Fuqing Zhou Ye Li Anchun |
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| Institution: | 1.Institute of Oceanology, Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences, Qingdao 266071,China;2.Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061,China;3.University of Chinese Academy of Sciences, Beijing 100049,China |
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| Abstract: | We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period. |
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| Keywords: | Amami Sankaku Basin Paleoclimate Clay minerals Provenance |
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