Movement History of the Microcontinents from the Tibetan Plateau Based on Paleomagnetic Results with Sufficient Sampling Units  

作　　者：Yiming Ma Weimin Ruan Chao Niu Tianshui Yang 

机构地区：[1]School of Earth Sciences,China University of Geosciences,Wuhan 430074,China [2]College of Earth Sciences,Guilin University of Technology,Guilin 541004,China [3]State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Beijing 100083,China

出　　处：《Journal of Earth Science》2022年第5期1072-1080,共9页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.41802242 and 42174089)。

摘　　要：Paleomagnetic results cannot be applied in global and regional tectonic reconstructions unless the paleosecular variation has been adequately averaged.However,how many sampling sites and samples are enough to calculate a reliable paleopole remains debated.Based on the relation among the sampling sites N,the precision parameter k,the virtual geomagnetic pole scatter s,and the confidence limit A_(95) of the paleopole,we find that 20 sites(samples)or more are required to yield a paleopole with an A_(95)≈5°based on a review of available paleomagnetic results from the Lhasa,Qiangtang and Tethyan Himalaya.Random samplings of Jurassic virtual geomagnetic poles from the Sangri area show that the Fisher mean pole with neglectable angle deviation can be obtained when sampling sites increase to 20.High-quality paleomagnetic results,with sites/samples number N/n≥~20–30,show that the Qiangtang,Lhasa,and Tethyan Himalaya moved northward in the Late Permian–Middle Triassic,Jurassic,and Cretaceous,respectively,and then accreted to Asia in the Late Triassic,Late Jurassic–Early Cretaceous and Paleocene–Early Eocene,respectively.

关 键 词：paleolatitude evolution Fisher mean random sampling sampling sites and samples continental collision TECTONICS 

分 类 号：P318.44[天文地球—固体地球物理学] P542[天文地球—地球物理学]