Lake-Level Oscillation Based on Sediment Strata and Geochemical Proxies Since 11,000 Year From Tengger Nuur, Inner Mongolia, China

A 794-cm section and core from Tengger Nuur (42°27´N, 110°42´E) in the Inner Mongolia Plateau had been collected. 8 effective AMS 14C data had been determined to set an age-depth model after minus about 1920 years carbon reservoir effective. Based on the multi-proxies grain size, carbonate-content, TOC-content, ratios of Mg/Ca and Sr/Ca, and carbonate carbon and oxygen isotope, palaeoenvironmental change had been reconstructed since the last deglacial. Tengger Nuur was very shallow during the last deglacial under cool and wet climate, especially much shallower at interval cold YD event. Although, temperature and humidity increased from the early Holocene ~10500 to 8750 cal a BP, low lake-level indicated that summer monsoon did not strengthen the modern monsoon boundary in Inner Mongolia. High monsoon precipitation made lake to expand during 8750~5000 cal a BP, but lake-level oscillated in a shallow state under higher evaporation. A low lake-level event interrupted with the cold-wet climate at interval 5450~5100 cal a BP. Summer monsoon receded gradually to keep a deep lake under high effective humidity during 5000~2000 cal a BP, and low lake-level events punctuated at intervals 4300~3980 cal a BP and 3700~2750 cal a BP. Lakes shrank gradually to be salinization or completely desiccation in the cold and dry westerly after 2000 cal a BP, but oscillated much lower lake-levels at four periods of 1900~1740 cal a BP, 1500~1050 cal a BP, 550~400 cal a BP (Little Ice Age), 100 cal a BP ~AD 1985. A weak eastern summer monsoon was in the early Holocene, and lake-level oscillation was controlled by the effective humidity in the arid and semi-arid area.