干旱区生态环境知识资源中心

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 similar to 53.5 Ma could be divided into four stages: a warm and seasonally arid climate between similar to 53.5 and 40 Ma, a cold and arid climate from similar to 40 to 26 Ma, a warm and humid climate between similar to 26 and 13.5 Ma, and a much colder and arid climate from similar to 13.5 to 2.5 Ma, respectively. The Mite crystallinity and sedimentary facies suggested that uplift events took place around >52-50, similar to 40-38, similar to 26-15, similar to 10-8, and <5 Ma in the 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 similar to 13.5 Ma, and the climate cycles of the East Asian monsoon might add additional influence.