Abstract by JunQing Yu oral presentation_15th East Eurasia International Workshop, Busan, Korea 2018 PRESENT RESPONSE OF QARHAN SALT FLAT TO THE WATERSHED HYDROCLIMATE: THE KEY TO UNDERSTANDING PAST CONDITIONS FOR EVAPORITIC DEPOSIT FORMATION JunQing Yu1,2*, Lisha Zhang1,2, Chunliang Gao1,2, Rongchang Hong1,3, Aiying Cheng1,2 1 Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 2 Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 3 University of Chinese Academy of Sciences, Beijing 100049, China Correspondence:
[email protected]; Tel.: +86-971-630-7153 Qarhan Salt Flat is the largest potash deposit in China and covers an area of 5856 km2 of the Qaidam Basin in the nothern Tibet-Qinghai Plateau. Although efforts on the study of the evaporite deposit were tremendous in the past 60 years, answers to the following questions remained inconclusive: (1) the cause and commencement timing of the evaporitic deposition and (2) when and what resulted in the shift of evaporitic deposition to a playa environment. A deep paleo-lake prior to the evaporite deposit formation, as hypothesized by previous studies, is proven unlikely by increasing evidence from sedimentologic and geomorphic studies. Bieletan, the westernmost sub-playa of Qarhan today, did not belong to the uniform Qarhan Salt Flat until the beginning of the deposition of the top 20-m evaporitic sequence, based on both the configuration of evaporitic strata and the distribution pattern of the lithium deposit.