青藏高原东北缘循化-化隆地区新生代沉积古地理演化  

Cenozoic Sedimentary Paleogeography Evolution of Xunhua-Hualong Area,Northwestern Qinghai-Tibet Plateau

作　　者：骆满生[1] 张克信[1,2] 林启祥[2] 张楗钰[1] 陈奋宁[1] 徐亚东[1] 陈锐明[1] 

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,武汉430074 [2]中国地质大学地球科学学院,武汉430074

出　　处：《地质科技情报》2010年第3期23-31,共9页Geological Science and Technology Information

基　　金：中国地质调查局国家青藏专项项目(1212010610103);国家自然科学创新研究群体基金项目(40621002);教育部创新团队发展计划项目(IRT0546)

摘　　要：通过详细分析和对比循化-化隆盆地及邻区新生代沉积序列,将研究区新生代沉积古地理演化划分为3个阶段:(1)渐新世,西秦岭逆冲带、拉脊山逆冲带抬升,循化-化隆盆地压陷下沉,接受以砾岩夹砂岩为主的洪冲积扇和山区河流相沉积,称他拉组。他拉组古流向主要为北东向及北北西向,与盆地南缘的西秦岭北缘隆起带基本垂直或平行,西北边缘古流向为南东东向。(2)中新世—上新世早期,经过渐新世洪冲积填平,很快进入河流三角洲充填阶段,并在中新世早期进入湖泊环境接受沉积。中新世是循化-化隆盆地、临夏盆地、定西-兰州盆地湖盆面积扩展最大期,循化-化隆盆地往东与临夏盆地连通,总体上构成向东张开的大型压陷盆地。这一时期,盆地多以湖泊和湖相三角洲、冲洪积平原相沉积为主。盆地在循化、尖扎、化隆等地发育大面积咸水湖相沉积。盆地四周发育冲洪积扇和冲洪积平原相沉积,在同仁往北、民和往南发育河流相、三角洲相沉积。(3)上新世3.6 Ma左右,为临夏组之上的积石组砾岩发育期。由于周缘山系强烈逆冲与盆地整体隆升,导致积石组与下伏临夏组何王家段之间发育沉积间断与不整面,区域上同仁盆地、甘加盆地、桑科盆地和定西-兰州盆地全部结束沉积。3.6 Ma以后盆地内分布的上新世积石组巨砾岩是该时期周缘山系进一步隆升的沉积响应。循化-化隆盆地与临夏盆地被积石山隆起带分割,盆地主要物源为拉脊山隆起带和西秦岭隆起带。盆地在循化县尕楞乡宗务一带发育的积石组冲洪积扇砾岩堆积最厚。With detailed analyses and comparison of the Cenozoic sedimentary sequence of Xunhua-Hualong and their neighboring areas,the Cenozoic sedimentary paleogeography evolution of the studied areas is divided into three stages.（1） Oligocene,in which West Qinling thrust belt,Lajishan thrust belt and Maxianshan thrust belt were uplifted in accompany with the pressing and subsidence of Xunhua-Hualong Basin,receiving mainly alluvial fan of conglomerate with sandstone,called Tala Formation.The paleoflow direction of Tala Formation mainly is NE and NNW,vertical to the northern uplift belt of the West Qinling at the southern of the basin,or SEE parallel to the paleoflow of the northwest.（2） Miocene-early Pliocene,when,with the alluvial of Oligocene,the Xunhua-Hualong Basin received the filling of river delta sediments followed by the quick filling of the river delta,receiving sediments of lacustrine environment in the early Miocene.Miocene is the stage of the greatest extension area in the Xunhua-Hulong,Linxia and Dingxi-Lanzhou basins.Xunhua-Hualong Basin connects Linxia Basin westward,constituting a giant open pressed subsidence basin wholly.At this time,the basin mainly was involved with deposition of lacustrine delta and alluvial plain facies.The saline lacustrine sediments developed in a large area of Xunhua,Jianzha,Hualong etc.Surrounding the basin,alluvial fan and plain facies sediments were developed,west of Tongren,while in the south of Minhe,there developed river,delta sedimentary facies.（3） At about 3.6 Ma of Pliocene,conglomerate of Jishi Formation developed over the Linxia Formation.The intensive overthrust of the surrounding mountain and whole uplift of the basin resulted in the development of hiatus and unconformity plain of Jishi Formation and the underlying Wangjia Group of Linxia Formation.Regionally,Tongren,Ganjia,Sangke and Dingxi-Lanzhou basins all finished their deposition.After 3.6 Ma,giant conglomerate of Pliocene Jishi Formation should be the sedimentary response to the further uplift of t

关 键 词：古地理 物源 沉积 循化-化隆盆地 新生代 

分 类 号：P534.6[天文地球—古生物学与地层学]