GU Jiani
School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, ChinaCHEN Andong
MNR Key Laboratory of Saline Lake Resources and Environments, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaLIU Jiajun
School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, ChinaHAN Guang
Qinghai Provincial Key Laboratory of Exploration and Research on Salt Lake Resources in the Qaidam Basin, Qaidam Integrated Geological Exploration Institute of Qinghai Province, Golmud, Qinghai 816000, ChinaWANG Xuefeng
Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, ChinaThis study was supported by the National Natural Science Foundation of China (Grant Nos. 41902190 and 42003044), the Geological Survey Project of China (Grant No. DD20221913) and the Qinghai Geological Exploration Fund (Grant No. 2020021068kc035). The drilling project of borehole AZK02 was performed by the Qaidam Integrated Geological Exploration Institute of Qinghai Province. We thank Prof. MA Zhibang for his assistance with U-Th dating.
The Quaternary was the main evaporite deposition period in the Qaidam Basin (QB), but the correlation between the evaporite deposition period and the glacial period is still unclear. In this study, the research objects are primarily evaporite-bearing strata in a 461.58 m-long drill core in the QB. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were applied to study the evaporite minerals, U-Th dating being applied to construct the 230Th geochronological framework. Evaporite deposition from Marine Isotope Stage (MIS) 15 to MIS 4 in the borehole was reconstructed via mineralogical and geochronological data. The evaporite minerals are mainly halite (NaCl), mirabilite (Na2SO4·10H2O), thenardite (Na2SO4) and gypsum (CaSO4·2H2O). A total of 9 effective 230Th data points, ranging from 492.5 ± 43.0 ka to 62.0 ± 11.9 ka, were obtained. The depositional age of the earliest halite layer in the borehole is 592.5–563.0 ka. There were mirabilite deposits in the QB during the cold glacial environment of MIS 6. During MIS 4, the study area desiccated, with mirabilite and halite being deposited. This study suggests that mirabilite is an indicator mineral for the glacial environment in the QB, while halite deposition does not correspond well to glaciation.
GU Jiani, CHEN Andong, LIU Jiajun, HAN Guang, WANG Xuefeng.2022. Connections between Evaporite Deposition and Glacial Periods since the Middle Pleistocene in Salt Lakes in the Western Qaidam Basin, China[J]. Acta Geologica Sinica(),96(5):1704-1715
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