青藏高原新生代以来气候环境演化的粘土矿物学特征  

Paleoclimate Evolution of the Qinghai-Tibet Plateau since the Cenozoic

作　　者：洪汉烈[1,2] 王朝文[2] 徐耀明[2] 张克信[1,2] 殷科[2] 

机构地区：[1]中国地质大学生物地质与环境地质教育部重点实验室,湖北武汉430074 [2]中国地质大学地球科学院,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2010年第5期728-736,共9页Earth Science-Journal of China University of Geosciences

基　　金：中国地质调查局项目(No.1212010610103);国家自然科学基金项目(Nos.40921062;40830212)

摘　　要：为探究青藏高原的气候环境演化,对青藏高原不同部位的盆地沉积物的粘土矿物特征进行深入系统的研究.结果表明,古新世阶段-始新世阶段时期,青藏高原古气候以行星风系居主导地位,青藏高原北部以温暖和季节性干旱为特征.柴达木地区在～36Ma的降温事件则明显早于全球降温事件(～34Ma)近2Ma.在渐新世(34～23Ma)期间,古气候以干旱炎热为特征,但气温相对要低于始新世.在中新世-上新世(23.0～2.6Ma)期间,青藏高原北缘的柴达木、循化盆地均在～21.5Ma发生气候变冷事件,而8～7Ma的气候变化事件遍及整个青藏高原.在藏南的吉隆盆地、青藏高原西北部的叶城盆地,～1.8Ma之前的盆地沉积物中仍然有相当高含量的蒙脱石,说明这些地区在～1.8Ma之前,虽然总体上气候变冷、变干,但仍然处于一种相对湿润的气候环境.Clay mineralogy of sediments of the basins in different locations of the Qinghai-Tibet plateau was investigated to reveal the paleoclimate evolution in Tibet. Our results show that the planetary wind system prevailed over the Paleocene-Eocene in Tibet. A rapid cooling in Qaidam was found in -36 Ma, prior to the global cooling event by -2 Ma. In the Oligocene, paleoclimate was warm and dry and the temperature was lower than that of the previous stage. In Miocene-Pliocene period cooling event was found in -21.5 Ma in Qaidam and Xunhua basins, northeastern Tibet. Climate change in 8--7 Ma occurred in the whole Qinghai-Tibet plateau. In Gyirong, southern Tibet and in Yecheng, western Tibet, smectite occurred in a certain amount in the sediments prior to - 1.8 Ma, indicating that climate was relatively humid in these regions prior to -1.8 Ma though the climate changed into cool and dry in the Qinghai-Tibet plateau.

关 键 词：青藏高原 柴达木盆地 札达盆地 叶城盆地 粘土矿物 古气候 

分 类 号：P534[天文地球—古生物学与地层学]