青藏高原沱沱河盆地渐新—中新世沉积环境分析  

Oligo-Miocene Depositional Environment of the Tuotuohe Basin, Central Tibetan Plateau

作　　者：刘志飞[1] 王成善[2] 金玮[3] 伊海生[3] 郑洪波[1] 赵西西[4] 李亚林[3] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092 [2]中国地质大学地球科学学院,北京100083 [3]成都理工大学沉积地质研究所,成都610059 [4]美国加州大学构造研究所和地球科学系,圣克鲁斯ca95064

出　　处：《沉积学报》2005年第2期210-217,共8页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(批准号:40102010;40321603;40446003和40202022);上海市青年科技启明星计划(03QE14051);青藏高原1:25万温泉兵站幅(I46C003002)区域地质调查项目联合资助.

摘　　要：沱沱河盆地保存着青藏高原内部至今发现最完整的渐新世至中新世连续沉积记录,由渐新世雅西措群(31.3～23.8Ma)和早中新世五道梁群(23.8～21.8Ma)组成,总厚度2393m。雅西措群主要为紫红色、砖红色砂岩、粉砂岩与泥岩韵律互层,五道梁群为一套内陆湖泊相泥灰岩、内碎屑灰岩和叠层石灰岩沉积。沱沱河盆地渐新—中新世沉积环境经历了3个阶段的演化:(1)早渐新世,以河流环境为主,古水流以北向为主,反映古气候条件比较干燥;(2)中晚渐新世,以湖泊环境为主,古水流以东北向为主,古气候条件相对温暖潮湿;(3)晚渐新世至早中新世,主要为湖泊环境,古水流转为南向,沉积岩性由雅西措群项部的砂泥岩互层为主转变为五道梁群的泥灰岩为主,反映当时的物源区发生重大转变,构造活动趋于稳定,古气候条件由温暖潮湿转为干燥。沱沱河盆地渐新—中新世气候和构造活动历史对于研究青藏高原早期隆升作用和全球气候变化都有重要意义。A continuous sedimentary record throughout Oligocene to Miocene was discovered in the Tuotuohe Basin and is considered as the most integrated Oligo-Miocene record within the Tibetan Plateau, observed so far. The record includes the Oligocene Yaxicuo Group （31.3-23.8 Ma） and the Early Miocene Wudaoliang Group （31.3-23.8 Ma） with a total thickness of 2393 m. The Yaxicuo Group consists mainly of violet and reddish brown, alternating sandstone, siltstone, and mudstone. The Wudaoliang Group consists of lacustrine marl, intramicrite, and stromatolitic limestone. The Oligo-Miocene evolution of depositional environment of the Tuotuohe Basin underwent three periods： （1） early Oligocene, mainly fluvial environment with mainly northward paleocurrrent and arid paleoclimate; （2） middle-late Oligocene, mainly lacustrine environment with mainly northeastward paleocurrent and warm and humid paleoclimate; （3） latest Oligocene to early Miocene, lacustrine environment with southward paleocurrent. During the third period, the lithology changed from alternating sandstone and mudstone of the upper Yaxicuo Group to mainly marl of the Wudaoliang Group, suggesting the significant shift of sediment provenance, the stable trending of tectonic movement, and the aridity of paleoclimate condition. The Oligo-Miocene paleoclimate and tectonic evolution of the Tuotuohe Basin has displayed its significance for understanding the early uplift of the Tibetan Plateau and the global climate change.

关 键 词：沉积环 境雅西措群 五道梁群 渐新一中新世 沱沱河盆地 青藏高原 

分 类 号：P512.2[天文地球—地质学]