摘要
采用接收函数方法,研究南、北松潘-甘孜块体及扬子板块的壳幔过渡带结构,得到3个不同构造块体的壳幔过渡带厚度和速度结构。结果显示,南松潘-甘孜块体壳幔过渡带厚度为1.79~3.4km,速度结构为高低速相间结构,该块体壳幔过渡带不断变厚,改变了原有的壳幔过渡带温压条件,且东南东北向都有剧烈的构造活动,产生高、低速相间的速度结构;巴颜喀拉松潘-甘孜块体壳幔过渡带厚度为2.22~3.72km,该块体受到持续挤压,壳幔过渡带逐渐变厚,逐渐改变壳幔过渡带温压条件,形成速度渐变结构;扬子块体壳幔过渡带厚度为0.86~1.58km,扬子块体四川盆地有坚硬的岩石圈,壳幔过渡带没有遭受破坏,为完好的一级间断面,过渡带厚度较薄,结构为速度突变结构。
In this paper,we study the crust-mantle transition zone structure of the south and north Songpan-Ganzi and the Yangtze plate(SSGT,BY-SG,YZB).The thickness and velocity structure of the crust-mantle transition zone of three different tectonic blocks are obtained by the receiver function method.It shows that the thickness of the transition zone of the SSGT block is 1.79-3.4 km,with an alternating velocity structure.The transition zone of the crust-mantle is getting thicker,breaking the original crust-mantle transition zone temperature and pressure conditions.Besides,it has a strong tectonic activity in the southeastern northeast,resulting in an alternating velocity structure.The thickness of the transition zone of the BY-SG block is 2.22-3.72 km,and the velocity structure is a gradual velocity structure.This block has been suffering the effects of continuous compression,gradually changing the temperature and pressure conditions of the transitional zone of the crust and mantle,forming the velocity gradient structure.The YZB block crust-mantle transition zone is 0.86-1.58 km,and the velocity structure is the velocity instantaneous structure.The crust-mantle transition zone in Sichuan basin(YZB)is a good first-order discontinuity,and the transition zone is thinner and the structure is a velocity instantaneous structure.
作者
戴强
王夫运
赵延娜
DAI Qiang;WANG Fuyun;ZHAO Yanna(Institute of Geophysics, CEA, 5 South-Minzudaxue Road, Beijing 100081, China;Geophysics Exploration Center, CEA, 75 Wenhua Road, Zhengzhou 450002, China)
出处
《大地测量与地球动力学》
CSCD
北大核心
2018年第7期723-728,共6页
Journal of Geodesy and Geodynamics
基金
川滇国家地震监测预报试验场项目(2016CESE0103)~~