塔里木盆地巴楚地区上泥盆统-下石炭统沉积-物源记录及其构造演化

发布时间：2018-04-16 05:33

本文选题：巴楚地区 + 上泥盆统-下石炭统　；参考：《地球科学》2017年03期

【摘要】：泥盆纪-石炭纪是南天山洋-塔里木盆地北部陆缘构造演化的关键时期.选取塔里木盆地巴楚地区上泥盆统-下石炭统露头剖面,在沉积体系、碎屑组分、重矿物组合分析基础上,重点通过LA-ICP-MS分析砂岩样品.结果表明,上泥盆统-下石炭统砂岩碎屑颗粒以单晶石英为主,(变质)结晶岩岩屑极少,物源构造属性主要指示陆块物源区;重矿物组合以锆石、电气石和TiO_2矿物等稳定重矿物为主,反映相对远距离的源汇体系和稳定的构造背景;2个年代学样品具有类似的碎屑锆石U-Pb年龄组成和Hf同位素特征,主要反映了383~479Ma、710~932Ma、1 752~1 936Ma、2 419~2 597Ma共4期构造热事件,并以前两期为主.对比研究显示,上述碎屑物源以塔里木盆地内古隆起为主,同时还可能有来自阿尔金造山带、西昆仑造山带的再旋回沉积.但并没有记录到来自盆地北侧造山带和岛弧的物源信息,说明该时期南天山洋盆并没有闭合,塔里木盆地北缘西部可能不存在洋盆的向南俯冲,晚泥盆世-早石炭世其可能为被动大陆边缘.
[Abstract]:Devonian-Carboniferous is the key period of tectonic evolution in the northern continental margin of South Tianshan Ocean-Tarim Basin.The outcrop section of Upper Devonian and Lower Carboniferous in Bachu area of Tarim Basin is selected. Based on the analysis of sedimentary system, clastic composition and heavy mineral assemblage, sandstone samples are analyzed by LA-ICP-MS.The results show that the detrital grains of the Upper Devonian and Lower Carboniferous sandstone are mainly composed of single crystal quartz and metamorphic rocks. The source structure attributes mainly indicate the source area of the continental block, and the heavy mineral assemblage is composed of zircon and zircon.The stable heavy minerals, such as tourmaline and TiO_2 minerals, mainly reflect a relatively long distance source and sink system and stable tectonic setting. The two chronological samples have similar U-Pb age composition and HF isotopic characteristics of clastic zircon.It mainly reflects the 4 tectonic thermal events in the first two periods of 383Y479 Ma 710 ~ 932 Ma ~ 1 752 ~ 1 936 Ma ~ (2 419) ~ 2 597Ma.Comparative study shows that the above clastic material sources are mainly paleouplift in the Tarim basin, and there may also be recyclic deposits from the Altun orogenic belt and the West Kunlun orogenic belt.However, no provenance information was recorded from the northern orogenic belt and island arc of the basin, indicating that the southern Tianshan ocean basin was not closed during this period, and that there may be no southward subduction of the ocean basin in the western part of the northern margin of the Tarim basin.The late Devonian to early Carboniferous may be passive continental margin.
【作者单位】：山西大同大学煤炭工程学院;中国科学院地质与地球物理研究所;中国石油天然气股份公司大庆油田博士后科研工作站;北京市地热研究院;
【基金】：国家自然科学基金项目(Nos.40972085,41372120) 国家重大专项(No.2011ZX05008-003)
【分类号】：P534.4

【相似文献】