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cje ›› 2010, Vol. 29 ›› Issue (05): 923-932.

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Clay mineralogy and its palaeoclimatic indicative significance of Miocene-Pliocene sediments in Qimugan of Xinjiang.

DU Juan1;HONG Han-lie1;ZHANG Ke-xin2;YIN Ke1;XU Yao-ming1;DENG Yan-ping1;CHEN Rui-ming1;BI Xiang-yang1
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  1. 1Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;2Key Laboratory of Biogeology and Environmental Geology, Ministry of education, Wuhan 430074, |China
  • Online:2010-05-10 Published:2010-05-10

Abstract: To reconstruct the palaeoclimte of Miocene-Pliocene in Qimugan of Xinjiang, sediments were collected, and their clay minerals relative proportion, assemblage, and micromorphology were determined by the methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM). In early Miocene-early mid Miocene sediments, illite and chlorite were the main clay minerals, and montmorillonite was minor, indicating an arid palaeoclimate prevailed over the period. In late mid Miocene-early late Miocene sediments, illite content decreased slightly, and montmorillonite and kaolinite were minor, suggesting a relatively warm and humid palaeoclimate. The mid late Miocene sediments had the similar clay minerals assemblage as the early Miocene sediments, suggesting the similar climate conditions to the early Miocene age. In late late-Miocene-Pliocene sediments, illite content exhibited a decrease trend, while montmorillonite and kaolinite contents were in reverse, suggesting a relatively warm and humid palaeoclimate. However, the abundant illite and chlorite throughout the Miocene-Pliocene sediments in Qimugan of Xinjiang indicated a general cold and dry climate during the period, and the palaeoclimate experienced two cycles of cold and dry to relatively warm and humid, and the climate of the Miocene was drier than that of the Pliocene.

Key words: Marine Cage Aquaculture, Eutrophication, Marine environmental pollution