| 30 ka以来东阿拉伯海U1456站位粘土粒级碎屑沉积物来源及其古环境意义 |
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| 引用本文： | 陈红瑾,徐兆凯,蔡明江,李铁刚.30 ka以来东阿拉伯海U1456站位粘土粒级碎屑沉积物来源及其古环境意义[J].地球科学,2019,44(8):2803-2817. |
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| 作者姓名： | 陈红瑾 徐兆凯 蔡明江 李铁刚 |
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| 作者单位： | 1.中国科学院海洋研究所海洋地质与环境重点实验室, 山东青岛 266071 |
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| 基金项目： | 中国科学院战略性先导科技专项(A类)XDA11030104国家自然科学基金项目41106043国家自然科学基金委员会-山东省人民政府海洋科学研究中心联合资助项目U1606401国家自然科学基金项目41676038国家海洋局全球变化与海气相互作用专项项目GASI-GEOGE-06-02国家海洋局全球变化与海气相互作用专项项目GASI-GEOGE-04国家海洋局全球变化与海气相互作用专项项目GASI-GEOGE-02国家自然科学基金项目41230959国家自然科学基金项目41476043国家自然科学基金项目41376064 |
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| 摘 要： | 通过对国际大洋发现计划U1456站位沉积物AMS 14C年代、粘土矿物、常量元素及粒度组成的综合分析，探讨了东阿拉伯海粘土粒级碎屑沉积物的源-汇过程及其古环境指示意义.30 ka以来U1456站位的粘土矿物组合以蒙脱石和伊利石为主，并含有少量的绿泥石和高岭石.物源分析结果表明粘土粒级碎屑沉积物主要来自于印度河与德干高原.30 ka以来西南季风很可能是影响喜马拉雅山脉以及印度大陆风化剥蚀的重要因素.在西南季风减弱的阶段，印度河物源端元对研究区的输入量减少，这可能与此时热带辐合带的南移及末次冰盛期喜马拉雅山脉冰川覆盖面积的增加有关，从而导致印度河径流量及喜马拉雅山脉可供风化剥蚀的区域减少.K/Al比值指示的源区大陆化学风化作用强度与前人重建的西南季风记录间较为同步，在东阿拉伯海可以作为晚第四纪以来西南季风演化的有效重建指标.
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| 关 键 词： | 东阿拉伯海 粘土矿物 常量元素 物质来源 风化剥蚀 西南季风 |
| 收稿时间： | 2019-01-18 |
Provenance of Clay-Sized Detrital Sediments and Its Paleoenvironmental Implications at Site U1456 in the Eastern Arabian Sea since 30 ka |
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| Abstract: | AMS 14C dating, clay minerals, major elements and grain size at site U1456 from International Ocean Discovery Program were analyzed, in order to constrain the source-to-sink processes of clay-sized detrital sediments and their paleoenvironmental significance in the eastern Arabian Sea. The clay mineral assemblages at site U1456 since 30 ka are dominated by smectite and illite, with minor chlorite and kaolinite. Provenance analysis results suggest that clay-sized detrital sediments are primarily derived from the Indus River and Deccan Trap. Southwest Asian monsoon probably is the main factor affecting the weathering and erosion in the western Himalaya and the Indian subcontinent since 30 ka. Relatively reduced contribution from the Indus River to the study area during weak southwest Asian monsoon intervals should correlate with the southward migration of the Intertropical Convergence Zone and the extension of glacial cover over the Himalayas during the Last Glacial Maximum, and thus reduction in the Indus River runoff as well as available exposure area for erosion and weathering over the Himalayas. The weathering and erosion on the continent revealed by K/Al ratio show coherent variations to the previous southwest Asian monsoon records, indicating the efficiency of K/Al ratio for tracking the regional climate signal in the eastern Arabian Sea since the late Quaternary. |
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