Regional differences in crustal structure of the North China Craton from receiver functions

作     者：WEI ZiGen CHU RiSheng CHEN Ling Wei Z G;Chu R S;Chen L

作者机构：State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2015年第58卷第10期

页      面：2200-2210页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 

基　　金：supported by the National Basic Research Program of China(Grant No.2013CB733203) the National Natural Science Foundation of China(Grant Nos.41225016 41125015) the National Science and Technology Major of China(Grant No.2011ZX05008-001) 

主　　题：North China Craton Moho depth Poisson's ratio gravitational equilibrium receiver function amplitude regional difference in crust 

摘      要：Moho depth and crustal average Poisson＇s ratio for 823 stations are obtained by H-n： stacking of receiver functions. These, to- gether with topography and receiver function amplitude information, were used to study the crustal structure beneath the North China Craton （NCC）. The results suggest that modified and preserved crust coexist beneath the craton with generally Airy-type isostatic equilibrium. The equilibrium is relatively low in the eastern NCC and some local areas in the central and western NCC, which correlates well with regional geology and tectonic features. Major differences in the crust were observed beneath the eastern, central, and western NCC, with average Moho depths of 33, 37, and 42 km and average Poisson＇s ratios of 0.268, 0.267 and 0.264, respectively. Abnormal Moho depths and Poisson＇s ratios are mainly present in the rift zones, the northern and southern edges of the central NCC, and tectonic boundaries. The crust beneath Ordos retains the characteristics of typical craton. Poisson＇s ratio increases roughly linearly as Moho depth decreases in all three parts of the NCC with different slopes. Receiver function amplitudes are relatively large in the northern edge of the eastern and central NCC, and small in and near the rifts. The Yanshan Mountains and southern part of the Shanxi rift show small-scale variations in the receiver-function ampli- tudes. These observations suggest that overall modification and thinning in the crust occurred in the eastern NCC, and local crustal modification occurred in the central and westem NCC. Different crustal structures in the eastern, central, and western NCC suggest different modification processes and mechanisms. The overall destruction of the crustal structure in the eastern NCC is probably due to the westward subduction of the Pacific Plate during the Meso-Cenozoic time; the local modifications of the crust in the central and western NCC may be due to repeated reactivations at zones with a heterogeneous s