青藏高原北羌塘块体中—晚三叠世古地磁研究  

Paleomagnetic data from the Middle-Late Triassic rocks of Qiangtang Block,Qinghai-Tibet plateau,China

作　　者：周亚楠[1] 程鑫[1] 邵瑞琦 张伟杰 卫弼天 刘雨纯 吴汉宁[1] ZHOU Yanan;CHENG Xin;SHAO Ruiqi;ZHANG Weijie;WEI Bitian;LIU Yuchun;WU Hanning(Department of Geology/State Key Laboratory of Continental Dynamics,Northwest University,Xi′an 710069,China)

机构地区：[1]西北大学地质学系/大陆动力学国家重点实验室

出　　处：《西北大学学报（自然科学版）》2019年第5期736-744,共9页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(91855211,41702233,41674070);陕西省教育厅科研计划项目(17JK0784)

摘　　要：对采自羌塘块体腹地中—晚三叠世图地层的87块样品(9个采点)进行了系统的岩石磁学与退磁实验,以探究羌塘地块的运动学过程与古—新特提斯洋转换等重大地质事件的相关性。结果表明,湖组火山岩样品中,主要载磁矿物为磁铁矿,而菊花山组灰岩样品中含有一定量的赤铁矿。大部分样品的退磁曲线具有双分量特征,除低温(场)分量之外,还获得了一中—高温(场)分量,通过与北羌塘块体已有的古地磁数据对比,推测该分量可能为早白垩世时期的重磁化结果。The Qiangtang Block is a main block which consists of the Tibet Plateau.Kinematic characteristics of this block closely related to the geological events such as the transformation between the Paleo-Tethys and Neo-Tethys.Thus,a combined paleomagnetic and rock magnetic study was conducted on the 87 samples(9 sites)which drilled form the Middle-Late Triassic strata of this block.The rock magnetic results indicated that the dominant magnetic carrier in Tuzhonghu volcanic samples are magnetite,and Juhuashan limestone samples contain hematite.Orthogonal vector diagrams of the Middle-Late Triassic specimens exhibited two components of magnetic remanence.Except for the low-temperature component,we obtained the middle-high temperature component which might be the remagnetization form the Late Cretaceous Period based on the comparison with previously published paleomagnetic data.

关 键 词：青藏高原 北羌塘地块 中—晚三叠世 古地磁 重磁化 

分 类 号：P318[天文地球—固体地球物理学]