Abstract

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Title:: Sedimentary Characteristics and Environmental Significance of Yadan Profile in the Northern Dabsun Lake of Qaidam Basin, China

Author(s):: LI Yu-hui; ZHENG Mian-ping; ZHAO Xiao-qing; WANG Hai-lei; 1. CCTEG Xi’an Research Institute, Xi’an 710077, Shaanxi, China; 2. MLR Key Laboratory of Saline Lake Resources and Environments, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China

Keywords:: sedimentary characteristic; paleoclimate; organic carbon; particle size; profile; salt lake; Qaidam Basin

Abstract:: NWW-direction Yadan geomorphology develops in the salt lake tectonic of the northern Dabsun Lake, Qaidam Basin. The sedimentary age, total organic carbon and particle size of Yadan profile were analyzed, and the relationship between the influencing factor and environmental climate was discussed. The results show that Yadan profile experiences Middle Pleistocene (~740 ka) climatic fluctuation process from dry to wet, and then to dry; the profile can be divided into three periods of 757.5-758.0, 741.6-757.5, 732.8-741.6 ka according to the relative obvious climatic change, corresponding to the stages of dry, wet and dry, respectively; the total organic carbon and median particle size of the profile show Middle Pleistocene (~740 ka) climatic-environmental changes in salt lake tectonic of the north slope, Sanhu depression, and reflect the weathering denudation of profile under the extrusion and uplift of tectonic movement in Middle Pleistocene and later, combined with the characteristics of typical fluvial delta facies and lacustrine facies of the profile; the bottom of the profile is fluvial facies sedimentary environment, and the top is lacustrine facies sedimentary environment, and experiences the water transgression and dereliction; the profile reflects that inland closed lakes have abundant water in warm-wet period, and have the characteristics of higher total organic carbon and smaller median particle size.