作　　者： ; ; (周尚哲）;

机构地区： 兰州大学资源环境学院西部环境教育部重点实验室

出　　处： 《第四纪研究》 2005年第5期620-629,共10页

摘　　要： 地处南亚季风区的沙鲁里山地区保留有丰富的第四纪冰川作用遗迹。文章通过ESR对冰碛物直接定年,结合冰碛地貌形态及其风化程度差异,结果表明沙鲁里山地区可能经历了4次规模较大的冰川作用。它们的ESR年代大约为19～16kaB.P.,48～43kaB.P.,135kaB.P.和571kaB.P.,分别与深海氧同位素第2、第3、第6、第16阶段对应。自沙鲁里山最早冰川作用(571kaB.P.)以后,该区经历了较大规模的抬升作用。MIS2和MIS4期间西南季风微弱,降水稀少,气温严寒,南亚季风区冰川发育受到一定限制。MIS3早期和晚期夏季风强盛,降水丰富,温度较高,水热平衡状况有利于冰川发育;MIS3中期气温较低,夏季风较强盛,降水较丰富,这种冷湿组合的气候条件有利于冰川发育。南亚季风区,MIS3期间的冰川前进规模不亚于甚至在某些区域超过了末次盛冰期,其主要原因可能是受制于夏季风的降水差异。 Abundant glacial sediments deposited since the earliest glaciation during the mid-Pleistocene are well preserved in the Shaluli Shan, Southeastern Tibetan Plateau, South Asian monsoonal region. Based on direct dating of the glacial deposits using Electron Spin Resonance （ESR）, combined with glacial landforms and weathering differences of tills, we believe that the Shaluli Shan probably has experienced 4 major glaciations. The timing of these glaciations was dated at 19-16kaB. P. , 48-43kaB. P. , 135kaB. P. and 571kaB. P. , corresponding to marine isotope stage （MIS） 2, 3, 6, and 16, respectively. The Shaluli Shan region has been dramatically uplifted since the earliest glaciation （571kaB. P.）. There are two crucial factors controlling the glacial development in the South Asian monsoon region-summer precipitation and temperature, which are dominated by the southwest monsoon and the summer incident radiation respectively. The cooler temperature and the lesser precipitation resulting from the weaker summer monsoon restricted the glaciations during MIS 2 and MIS 4 to a limited extent. During the early and late MIS 3, the summer monsoon was extremely strong with heavy precipitation. Though the temperature was relatively high, the combination of precipitation and temperature was favorable for glacier development. Owing to the cooler temperature and the heavier precipitation resulted from the stronger summer monsoon, the climate condition during MIS 3b also facilitated glacier advance. In the South Asian monsoonal region, the extent of glacier advance during MIS 3 was no less than that of the global LGM and even surpassed it in some areas. This was probably due to the differences of precipitation resulted from the summer monsoon. The intensity of the southwest monsoon is positively related to the contrast in insulation between the northern and southern hemispheres or between land and sea. The southwest monsoon during interglacials or interstadials was not always stronger than that of the glacial or stadi

关 键 词： 沙鲁里山 末次盛冰期 深海氧同位素第 阶段 西南季风 测年

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]