A mid to late Holocene exposure in a recently desiccated lake basin in western Inner Mongolia was investigated with regard to palaeoenvironmental changes and the overall climatic conditions in NW China between 2.7 and...A mid to late Holocene exposure in a recently desiccated lake basin in western Inner Mongolia was investigated with regard to palaeoenvironmental changes and the overall climatic conditions in NW China between 2.7 and 5.4 cal. ka BP. High lake levels of Lake Eastern Juyanze were recorded by ostracod assemblages, shell geochemistry and sedimentology between 5.1 and 4.1 cal. ka BP. Relatively humid conditions and a relatively strong influence of the Asian monsoon are indicated by palynological data for the corresponding period. Lake levels decreased afterwards and short-term regressive events occurred at about 4.1, 3.8 and 3.4 cal. ka BP. The overall trend towards lower lake levels culminated in repeated episodes of desiccation of Lake Eastern Juyanze between 3.2 and 2.9 cal. ka BP, in phase with very arid conditions inferred from the palynological record. Individual regressive events as well as the rapid environmental fluctuations of Lake Eastern Juyanze at about 3.0 cal. ka BP were regarded as driven by mid to late Holocene summer monsoon fluctuations, supported by the Dunde ice core record.展开更多
基金supported by the Deutsche Forschungsgemeinschaft(Grants No.Schu 694/10-l and Ri 809/5-1)the Deutscher Akademischer Austauschdienst(DAAD)for a Graduate Fellowship(Grant No.D/97/23142).
文摘A mid to late Holocene exposure in a recently desiccated lake basin in western Inner Mongolia was investigated with regard to palaeoenvironmental changes and the overall climatic conditions in NW China between 2.7 and 5.4 cal. ka BP. High lake levels of Lake Eastern Juyanze were recorded by ostracod assemblages, shell geochemistry and sedimentology between 5.1 and 4.1 cal. ka BP. Relatively humid conditions and a relatively strong influence of the Asian monsoon are indicated by palynological data for the corresponding period. Lake levels decreased afterwards and short-term regressive events occurred at about 4.1, 3.8 and 3.4 cal. ka BP. The overall trend towards lower lake levels culminated in repeated episodes of desiccation of Lake Eastern Juyanze between 3.2 and 2.9 cal. ka BP, in phase with very arid conditions inferred from the palynological record. Individual regressive events as well as the rapid environmental fluctuations of Lake Eastern Juyanze at about 3.0 cal. ka BP were regarded as driven by mid to late Holocene summer monsoon fluctuations, supported by the Dunde ice core record.
