QUATERNARY PALAEOCLIMATIC CHANGES RECORDED BY NATURAL GAMMA LOGGING CURVE IN QAIDAM BASIN
Chen Ye Yuan Linwang Zhou Chunlin Liu Zechun Coastal and Quaternary Institute of Geography School, Nanjing Normal University
Using natural gamma logging (GR) curves to analyse palaeoclimatic changes is a newly developed research field. Based on the analyses of a variety of palaeoclimatic indicators of the core samples from Well Sezhong 6,the model of inverse modeling of palaeoclimatic changes has been established. This model has been further introduced into Well Dacan 1 — the only well drilling through the Quaternary in the eastern Qaidam Basin. The high resolution GR curve of Well Dacan 1 has been used to reconstruct the time scale of a period of 2.85 Ma BP in the eastern Qaidam Basin. The palaeoclimatic changes in the eastern Qaidam Basin since 2.85 Ma BP are also discussed. In comparison with the record of Well ZK336 in Dalangtan area of the western Qaidam Basin, it is suggested that the palaeoclimatic changes of the Qaidam Basin were controlled by the astronomic orbital periods, and these changes tended to behave obvious regional characteristics. It is showed that the current Qaidam Basin is one of the best carriers of information such as the uplifting history of the Qinghai—Tibet Plateau, the global climatic and environmental changes. It is also indicated that GR curve can be a good indicator of the environmental and climatic changes of the inland arid basin.