临夏盆地新生代沉积物粒度记录与亚洲内陆干旱化  

Grain-size records of Cenozoic Lacustrine sediments from Linxia Basin and the aridification of Asian Inland

作　　者：徐先海[1] 方小敏[2] 宋春晖[3] 范马洁[3] 沈吉[4] 

机构地区：[1]安徽省安庆师范学院资源环境系,安庆246011 [2]中国科学院青藏高原研究所,北京100085 [3]兰州大学西部环境教育部重点实验室&兰州大学地理系,兰州730000 [4]中国科学院南京地理与湖泊研究所,南京210008

出　　处：《湖泊科学》2008年第1期65-75,共11页Journal of Lake Sciences

基　　金：国家自然科学基金重点基础项目(40334038)资助

摘　　要：临夏盆地毛沟剖面高分辨率粒度记录研究表明,29-7.4Ma间,临夏盆地的古气候一直保持相对稳定,而其中短暂的沉积相的改变是盆地对该期间青藏高原构造隆升事件的响应;从7.4Ma开始,流域外的风尘物质开始逐步被带人盆地,并经过了6.4Ma和5.3Ma的两次加速过程,揭示了我国西北内陆干旱气候可能从7.4Ma左右开始,且在6.4Ma和5.3Ma左右经过两次加强.通过与青藏高原构造隆升事件记录和全球气候记录对比。揭示高原在9-7Ma开始的逐步隆升和期后的阶段性加速隆升以及同期开始的全球变冷,尤其北极冰盖的形成和扩张可能是亚洲内陆干旱化的重要驱动机制.High-resolution grain size records from Maogou section in Linxia Basin were characterized with relative stable fluctuation from 29Ma and 7.4 Ma, and changes in several sedimentary facies responded to Tibetan uplift in some short intervals. At about 7.4Ma, aeolian dusts gradually entered into Linxia Basin, and input fluxes of aeolian dusts had two rapid increased phases respectively at about 6.4Ma and 5.3Ma, suggesting that NW China drying climate began at 7.4 Ma and strengthened rapidly at 6.4Ma and 5.3Ma. Comparing of our records with the Tibetan uplift and global climatic records, we found that the gradual uplift of the Tibetan Plateau and global cooling, especially the onset of Arctic ice sheet, since about 9-8 Ma, may be the two important forcing mechanisms for the fast aridification of Asian inland.

关 键 词：临夏盆地 粒度 干旱化 高原隆升 全球变冷 

分 类 号：P532[天文地球—古生物学与地层学]