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通过对黄土高原中部两个典型的风尘堆积序列的岩性和磁性地层研究 ,认为中国黄土高原风尘堆积的开始发育年龄至少约为 7.2 Ma B.P.。以红粘土和黄土—古土壤交互出现的风尘沉积 ,不仅真实地记录了东亚季风气候的形成演化 ,而且可能包含了青藏高原的阶段性隆升、北半球冰盖形成演化及大冰期发生等构造气候事件的印记。反映粉尘源区的干燥度及携带粉尘的大气环流强度的风尘沉积速率自 7.2 Ma B.P.开始、尤其是 4.5 Ma B.P.以来逐渐增大 ,似乎暗示了自新近纪以来亚洲内陆粉尘源区干旱化的逐级发展和东亚冬季风环流强度的逐渐增加
Based on the lithologic and magnetic stratigraphy of two typical dust deposition sequences in the central Loess Plateau, it is concluded that the onset of dust accumulation in the Loess Plateau of China is at least about 7.2 Ma BP. The deposition of dust and dust between loam and loess-paleosol not only truly records the formation and evolution of the East Asian monsoon climate, but also may include the tectonic climatic events such as the stage uplift of the Tibetan Plateau, the formation and evolution of the Northern Hemisphere ice sheet and the Great Ice Age Imprint. The dust deposition rate, which reflects the dryness of the dust source area and the atmospheric circulation intensity of the dust, began to increase from 7.2 Ma BP, especially 4.5 Ma BP, suggesting that the aridification of inland dust source areas in Asia since the Neogene Gradual development and East Asian winter monsoon circulation intensity gradually increased