摘要
昆仑山北坡的黄土主要来源于塔克拉玛干沙漠中的粉尘物质,是在干旱的草原环境下堆积形成的.昆仑山北麓一带年浮尘日数高达100d以上,黄土堆积持续进行.它是青藏高原现代地貌形成的标志沉积,不仅同现代大气降尘具有相似的生物气候环境,而且可能具有相似的环流条件.在干旱的气候背景上有过不同程度的气候波动.7000-5000a.B.P.为显著的相对湿润时期.
Based on the material composition, the geochemical nature, palynoflora study and agedating it is assumed safely that the loess is aeolian deposit mostly originating from the de-serts in Tarim Basin under fairly dry climate of steppe type, and overspreaded piled mainlyfrom the last glaciation maximum through Holocene period, which might be related to thetime when the Taklimakan deserts were extensively formed. The occurrence of the frequentmodern wind-blown dust precipitation along the south margin of Tarim appears to be themodern loess accumulation, meaning that the loess kept depositing strongly since the lastglaciation maximum. The palynofloras indicate that the biological environment associatedwith the loess deposition is quite similar with the modem one at the northern slope ofKunlun Mts. It is supposed that the modern lower general circulation, related to the loessformation, was completely set up probably in the last glaciation maximum. On the aridbackground occurred some moist fluctuations. Around 7 000 to 5 000 a.B.P. was a aromi-nent humid oscillation when thick soil developed ana snail. Succinea pfeiferi , withsemihumid habitat, thrived . it might be 50 to 100 mm more in annual rainfall than what itis today .
出处
《干旱区地理》
CSCD
北大核心
1991年第3期9-17,共9页
Arid Land Geography
基金
国家自然科学基金
