| 94–9 ka察尔汗盐湖的气候环境演化过程 |
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| 关键词:Qaidam Basin geochemical elements pollen environmental change Late Pleistocene |
| 基金项目:国家自然科学基金青年基金项目(编号: 41301045; 41302024) |
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| 摘要: |
| Chemical Elements in Core Sediments of the Qarhan Salt Lake and Palaeoclimate Evolution during 94–9 ka |
| A 102 m long drill core (ISL1A) was obtained from the Qarhan Salt Lake in central eastern Qaidam Basin, northeastern Tibetan Plateau. An age-depth model was established with AMS 14C and 230Th dating. Chemical elements analysis was carried out for the core sediments, and two important factors including runoff of the lake and evaporation were identified using Principal Component Analysis. The chemical elements analysis results were combined with pollen analysis, grain size and percentage of halite in the sediments so as to reveal the evolution of the Qarhan Salt Lake during Late Pleistocene. The result indicates that the paleo-Qarhan Lake experienced several desalt and salinization stages. During 94–52 ka, environmental proxies indicated freshwater to oligohaline conditions of the paleo-Qarhan Lake, the runoff and detrital input to the lake were relatively high and the steppe/desert steppe vegetation developed around the lake. After 52 ka, lake level decreased significantly in volume and salinity compared with previous periods of the Late Pleistocene, and desert steppe/desert vegetation developed around the lake. The increasing of runoff of the lake diluted the water body from a hyper-saline concentration to a brackish concentration during 34–24 ka. However, it is further noted that the range of lake expansion was limited during this stage. During 24–9 ka, cold and dry climate prevailed in the basin and the Qarhan Salt Lake finally evolved into a dry playa. These environmental changes and the variations of the lake level reflected by the environmental proxies of Qarhan Salt Lake sediments are supported by other environmental change records in Qaidam Basin as well as adjacent areas. |
| WEI Hai-cheng,FAN Qi-shun,AN Fu-yuan,SHAN Fa-shou,MA Hai-zhou,YUAN Qin,QIN Zhan-jie.2016.Chemical Elements in Core Sediments of the Qarhan Salt Lake and Palaeoclimate Evolution during 94–9 ka[J].Acta Geoscientica Sinica,37(2):193-203. |
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