Uranium Isotopic Composition and Constraints on the Provenance of the Qinghai-Tibet Plateau's Surface Dust
编号:114 访问权限:私有 更新:2023-04-14 20:04:58 浏览:178次 口头报告

报告开始:2023年05月08日 10:55(Asia/Shanghai)

报告时间:10min

所在会场:[2A] 2A、地球化学 [2A-3] 2A-3 地球化学

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摘要
The production and emission of aeolian dust can provide key information on the contemporary and historical links between geological evolution and climate. Here we use 234U/ 238U isotope ratios and the uranium (U) comminution age method on samples collected from Qinghai-Tibet Plateau (TP) surface dust and glacier snowpack/cryoconites to determine the erosion and potential transport provenance of the dust, regardless of petrological origin. The spatial variation of the ( 234U/ 238U) isotope ratios of TP dust showed relatively high values in the Songpan-Ganzi-Hoh Xil, Himalayan and the Kunlun-Qaidam-Qilian terranes, while showing relatively low ( 234U/ 238U) values in Lhasa and Qiangtang terranes, but among all samples the highest value appeared in the glaciation zone. Dust collected from nearby glacial areas with rugged terrain (e.g., the Qilian and Himalayan Mountains) have higher ( 234U/ 238U) values than those collected in the topologically flat non-glacial areas. These differences are consistent with elevated erosion rates and dust comminution-transport processes in glacial areas, which yield a major source for large quantities of fresh comminuted particles. Compared to sediments from other regions of the globe, the ( 234U/ 238U) values of the typical aeolian sinks (such as loess on the Loess Plateau and ice core dust, etc.) are generally lower in comparison to areas with high elevations where erosion rates are high. The ( 234U/ 238U) isotope values of TP dust tend to fall between the highelevation sites and the dust sinks, indicating the combined influence of short comminution times (tectonics, landscape dynamics, and glacial erosion) and long residence time on the TP. When compared with other central
Asian dust sources, U-Nd-Sr isotope signatures in TP dust are distinct and can be thus used as an effective tracer of dust provenance. Using U isotopes, we show that dust originating from the TP undergoes long-range transport and constitutes potentially significant component of the Asian and Northern Hemisphere atmospheric dust load.
关键词
青藏高原;铀同位素;,粉尘循环
报告人
焦晓瑜
中国科学院西北生态环境资源研究院

稿件作者
焦晓瑜 中国科学院西北生态环境资源研究院
董志文 中国科学院西北生态环境资源研究院
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重要日期
  • 会议日期

    05月05日

    2023

    05月08日

    2023

  • 03月31日 2023

    初稿截稿日期

  • 05月25日 2023

    注册截止日期

主办单位
青年地学论坛理事会
中国科学院青年创新促进会地学分会
承办单位
武汉大学
中国科学院精密测量科学与技术创新研究院
中国地质大学(武汉)
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