摘要
把柯坪断隆"还原"为塔里木板块的一部分,重塑了它与北邻的乌什地区和南邻的巴楚地区古生代 "分分""合合"的演化史,得到以下重要认识。(1)奥陶纪在乌什、柯坪和巴楚一间房地区发育以东西向的古吐木休克断层为南界的台盆; 该断层的西段后期被柯坪塔格断裂(东西走向段)迁就利用,中—东段后期因被肢解而"消失"。(2)柯坪地区最西部中泥盆世已有海相沉积,晚泥盆世—石炭纪海侵不断向东扩展;因南天山洋的消减在柯坪—阿克苏—库车一线形成横贯塔里木北缘的石炭纪隆起带,使得塔里木中—北部上泥盆统—石炭系的沉积相有清楚的空间展布规律。(3)据同位素年龄值将柯坪地区东段玄武岩的时代更正为早二叠世,强烈火成活动造成的热隆升使该地区早二叠世即出现陆相沉积;塔西北的其他地区石炭纪末—早二叠世普遍发生海侵。(4)从与南天山洋和西昆仑洋耦合演化的角度简要探讨了塔里木西北地区古生代的成盆动力学背景,认为古生代有东西向、北西向及北东向的控盆和控相断裂发育并总结了其后期演化的特点。
The paper restored the Kalpin Fault-Rise to be a part of the Tarim plate,which experienced similar development with the Bachu Fault-Rise during geohistory.The main knowledge on the Paleozoic sedimento-tectonic evolution of northwest Tarim are as follows.(1)The Ordovician northwest Tarim Basin,filled with calcareous turbidites,covered an area of Wushi,Kalpin and Yijianfang of Bachu,with the southern boundary being the paleo-Tumxuk fault. Later on,the western segment of the fault was accommodated and utilized by the Kalpintag fracture,while its middle-eastern segment was dismembered by a group of NW-striking fractures and disappeared.(2)There developed marine sediments of the Middle Devonian in the westmost part of Kalpin area,and the transgression expanded eastwards successively during the Late Devonian-Carboniferous.Caused by subduction of the South Tianshan Ocean,a Carboniferous rise occurred along Kalpin-Akesu-Kuqa,which traversed the northern margin of the Tarim plate.So the sedimentary facies changes of the Late Devonian-Carboniferous in the central-northern plate had a clear spatial regularity.(3)Based on systematic isotopic datings,the eruptive age of the basalt in eastern segment of Kalpin area(the Kupukuziman and Kaipaizileike Formations)is corrected to be the Early Permian,instead of the Middle Permian.The heat uplifting related to the violent igneous activity resulted in that the continental facies clastic rocks deposited there in the Early Permian,while transgression occurred and marine limestone deposited in other regions of northwest Tarim during the latest Carbonifeous-Early Permian.(4)The basin dynamic settings were explored briefly in the light of that the Paleozoic developing of northwest Tarim should be coupled with evolution of the South Tianshan and West Kunlun oceans to the north and to the south of the area respectively.The features of three Paleozoic groups of basin-controlling or facies-controlling fractures,namely,latitudinal,NW-striking as well as NE-striking ones,and their Meso-Cenozoic developing were summarized.
出处
《古地理学报》
CAS
CSCD
北大核心
2013年第2期203-218,共16页
Journal of Palaeogeography:Chinese Edition
关键词
沉积—构造演化
奥陶纪台盆
海侵
隆起
火成活动
成盆动力学
古生代
塔里木西北部
sedimento-tectonic evolution,Ordovician basin,transgression,uplift,igneous activity,basin dynamics,Paleozoic,northwest Tarim