藏南吉隆盆地中新世—早更新世沉积演化  

Late Miocene-Early Pleistocene sedimentary evolution in Gyirong Basin,southern Tibet

作　　者：陈奋宁[1] 徐亚东[2,3] 陈锐明[1] 江尚松[2,3] 

机构地区：[1]中国地质调查局西安地质矿产研究所,陕西西安710054 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074 [3]中国地质大学(武汉)地球科学学院,湖北武汉430074

出　　处：《地质通报》2013年第1期154-164,共11页Geological Bulletin of China

基　　金：中国地质调查局国家青藏专项项目<青藏高原新近纪隆升过程与地质事件群研究>(编号:1212011121261);国家自然科学基金项目(批准号:41102073);东昆仑成矿带基础地质综合研究(编号:1212011086005)

摘　　要：位于喜马拉雅北麓的吉隆盆地中新统旦增竹康组,为冲积扇-辫状河沉积。沃马组沉积演化自下而上依次为扇三角洲-滨浅湖-扇三角洲,总体上表现为进积-退积-进积的沉积旋回。沃马剖面在10～7.4Ma期间,古流向主体为SEE向;7.4～1.67Ma,古水流方向主体为SWW向,说明7.4Ma以后,吉隆盆地古地理格局发生显著变化,古地势由原来的西高东低转变为后期的东高西低。根据沉积学、磁性地层学、年代学等方面的研究资料,将10Ma以来吉隆盆地的湖盆演化大致划分为3个阶段:10～7.4Ma,湖盆裂陷形成期;7.4～3.6Ma,湖盆扩展与稳定发展期;3.6～1.67Ma,湖盆萎缩消亡期,代表了盆地周围喜山的3次隆升期,即10～7.4Ma、7.4～3.6Ma和3.6～1.67Ma,其中3.6～1.67Ma为强烈隆升期。The Gyrong Basin was located in the northern piedmont of the Himalayas. Sedimentary facies in Miocene Danzengzhukang Fom^ation of the basin are composed from the bottom upwards of alluvial fan-braided river. The Orma Formation consists of delta fa- cies-lacustrine thcies-delta facies from bottom to top, which represents a progradation-regradation-progradation sequence. The pale- ocurrent reflected in Orma section was mainly in SEE direction in 10--7.4Ma, and was in SWW direction in 7.4-1.67Ma. These data imply that the paleogeographic framework of Gyrong Basin changed drastically and its topography changed from high in the west and low in the east into high in the east and low in the west after 7.4Ma. Based on the sedimentary, magnetostratigraphic and chronologic data available, the authors hold that Gyrong Basin has experienced three evolutionary stages since 10Ma： 10-7.4Ma was the stage of rift and formation; 7.4-3.6Ma was the stage of expansion and steady development, an 3.6-1.67Ma was the stage of withering and ex- tinction. These three stages represented the three uphft period of the Himalays, which included 10-7.4Ma, 7.4-3.6Ma and 3.6- 1.67Ma, and the Himalayas was strongly uplifted during 3.6-1.67Ma.

关 键 词：吉隆盆地 中新世-早更新世 古流向 沉积演化 

分 类 号：P512.2[天文地球—地质学] P534.6