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高校地质学报 ›› 2021, Vol. 27 ›› Issue (3): 366-374.DOI: 10.16108/j.issn1006-7493.2020067

• 固体地球科学领域重点实验室联盟实验技术与应用年会十周年纪念专辑 • 上一篇    

中国沙漠的碎屑长石矿物与冰期风尘示踪

李 娟1,何 同2*   

  1. 1. 内生金属矿床成矿机制研究国家重点实验室,南京大学 地球科学与工程学院,南京 210023;
    2. 南京信息工程大学 地理科学学院,南京 210062
  • 出版日期:2021-06-20 发布日期:2021-06-21

Detrital Feldspars of the Chinese Deserts: Implications for Asian Dust Provenance

LI Juan1,HE Tong2*   

  1. 1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China;
    2. School of Geographic Sciences, Nanjing University of Information Science and Technology, Nanjing 210062, China
  • Online:2021-06-20 Published:2021-06-21

摘要: 文章采用了新型自动矿物相识别技术(INCA Mineral)对中国北方10个沙漠盆地以及蒙古戈壁沉积物的碎屑长石开展了矿物定量研究。钾长石/钠长石和钙质斜长石/石英的比值指示了沙漠沉积物的长石矿物含量特征,表现出显著的地球化学区域分布特证。沿着青藏高原北部边缘分布的塔克拉玛干、柴达木、腾格里、巴丹吉林与毛乌素沙漠的沉积物中两种长石矿物比值均较低;中亚造山带以北的古尔班通古特、蒙古戈壁、浑善达克、呼伦贝尔和科尔沁沙漠的沉积物中两种长石矿物指标均具有较高值。长石矿物含量特征揭示的“两单元”区域分布结果,可以由过去采用Nd-Sr-Hf同位素示踪结果来验证。东亚沙漠长石含量的二元空间分布特征,支持了构造成山控制盆地沉积物矿物成分的假说。黄土高原末次冰期黄土的长石含量特征,与青藏高原北缘的长石分布特征一致,该区域可能是末次冰期黄土高原物质的主要来源,但也并不排除中亚造山带物质通过远距离搬运传输对末次冰期风尘的贡献。

关键词: 中国沙漠, 碎屑长石矿物, 钾长石/钠长石比值, 末次冰期黄土, 青藏高原北缘

Abstract: Using an automated mineral identification technique (INCA-Mineral), we quantified the mineral compositions for the sediments that are collected from ten desert basins in East Asia. The mineralogical characteristics of felsic minerals were analyzed to determine the variation in spatial scale. Using the felsic component, e.g. quartz-plagioclase-K-feldspar compositions, results demonstrate that the desert basin along the Central Asian Orogenic Belt possess higher K-feldspar/albite ratios and higher Ca-plagioclase/quartz ratios, compared with that of the desert basins along northern Tibetan Plateau. The two end-member classification of desert sediments in East Asia was supported by previous studies using Nd-Sr-Hf isotopic fingerprinting method. The felsic mineralogical characteristic parameter showed similarity between the dust source deserts from the SDB and the glacial dusts on the Loess Plateau. These results strongly indicate that the northern Tibetan Plateau was the dominant dust material source for Chinese loess. Combined with the previous study by method of air mass back trajectory and geomorphology, the dust material contributions from the Central Asian Orogenic Belt was also potentially included via the long-distance wind transport.

Key words: Chinese deserts, detrital feldspars, K-feldspar/albite ratio, Chinese loess, northern Tibetan Plateau

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