摘要
Clay mineralogy and bulk mineral composition of Tertiary sediments in Qaidam were investigated using X-ray diffraction （XRD） and scanning electron microscopy in order to better understand regional climate change resulting from uplift of the Northeast Tibetan Plateau. Climate change in Qaidam since -53.5 Ma could be divided into four stages： a warm and seasonally arid climate between -53.5 and 40 Ma, a cold and arid climate from -40 to 26 Ma, a warm and humid climate between -26 and 13.5 Ma, and a much colder and arid climate from -13.5 to 2.5 Ma, respectively. The illite crystallinity and sedimentary facies suggested that uplift events took place around ＆gt;52–50, -40–38, -26–15, -10–8, and ＆lt;5 Ma inthe Qaidam region, respectively. The climate in Qaidam Basin could have been controlled by global climate prior to 13.5 Ma. As the Tibetan Plateau reached a significant elevation by -13.5 Ma, and the climate cycles of the East Asian monsoon might add additional influence.
Clay mineralogy and bulk mineral composition of Tertiary sediments in Qaidam were investigated using X-ray diffraction （XRD） and scanning electron microscopy in order to better understand regional climate change resulting from uplift of the Northeast Tibetan Plateau. Climate change in Qaidam since -53.5 Ma could be divided into four stages： a warm and seasonally arid climate between -53.5 and 40 Ma, a cold and arid climate from -40 to 26 Ma, a warm and humid climate between -26 and 13.5 Ma, and a much colder and arid climate from -13.5 to 2.5 Ma, respectively. The illite crystallinity and sedimentary facies suggested that uplift events took place around ＆gt;52–50, -40–38, -26–15, -10–8, and ＆lt;5 Ma inthe Qaidam region, respectively. The climate in Qaidam Basin could have been controlled by global climate prior to 13.5 Ma. As the Tibetan Plateau reached a significant elevation by -13.5 Ma, and the climate cycles of the East Asian monsoon might add additional influence.
基金
supported by the China Geological Survey(No.1212011121261)
the National Natural Science Foundation of China(Nos.41272053and41072030)
Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110145110001)
the Independent Research Project Foundation of State Key Laboratory of Biogeology and Envi-ronmental Geology,China University of Geosciences,Wuhan(No.GBL11307)
