华南中部地幔转换带厚度异常:海南地幔柱?  

Mantle transition zone thickness anomaly at middle Southern China by receiver function:evidence for Hainan Plume

作　　者：王冠之 陈永顺 张晨 盖增喜[1] 郭震 杨挺 葛天雨 WANG GuanZhi;CHEN YongShun;ZHANG Chen;GE ZengXi;GUO Zhen;YANG Ting;GE TianYu(Department of Geophysics,Peking University,Beijing 100871,China;Department of Ocean Science and Engineering,Southern University of Science and Technology,Guangdong Shenzhen 518055,China;ShanghaiSheshan National Geophysical Observatory,Shanghai 201602,China)

机构地区：[1]北京大学理论与应用地球物理研究所,北京100871 [2]南方科技大学海洋科学与工程系,广东深圳518055 [3]上海佘山地球物理国家野外科学观测研究站,上海201602

出　　处：《地球物理学报》2022年第10期3871-3880,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41890814,U1901602);大洋“十三五”项目(DY35-G2-1-01);广东省自然科学基金(2018A030310121);深圳市海外高层次人才创新创业专项资金团队资助项目(KQTD20170810111725321);中国地质科学院地质调查项目(DD20160082)资助。

摘　　要：本文利用84个布设于华南中部地区的流动地震台站记录的239个远震地震事件的波形资料,通过接收函数方法得到了华南大陆中部地区的地幔410 km和660 km间断面起伏与地幔转换带厚度变化.结果表明在华夏块体下方转换带厚度明显减薄10~25 km,尤其是在南部靠近海岸线附近(23.7°N,114.5°E)存在一个直径约200 km的转换带厚度异常区域(减薄约25 km),可能揭示海南地幔柱在该处上涌穿透660 km间断面进入地幔,在地幔转换带向周围扩散,热的地幔物质穿过410 km间断面继续上涌,造成了华夏块体下方上地幔大范围的低速异常,以及在雷州半岛和沿岸造成大范围的新生代玄武岩活动.We have presented the 410 km and 660 km mantle discontinuity structure and mantle transition zone(MTZ) thickness beneath the middle Southern China Block using seismic data recorded by 84 portable seismic stations in the region by receiver function method. We found that transition zone thickness beneath Cathaysia Block is thinned 10~25 km obviously, the MTZ thinned anomalously within an area approximately 200 km in diameter centered(23.7°N,114.5°E),where the Hainan mantle plume may upwell into upper mantle, the continuous upwelling of hot mantle materials resulted in a wide range of low velocity anomalies in the upper mantle beneath the Cathaysia Block(above 410 km), also a large range of Cenozoic basalts in Leizhou Peninsula and coastal areas.

关 键 词：接收函数 410km间断面 660km间断面 转换带厚度 华夏块体 扬子克拉通 

分 类 号：P315[天文地球—地震学] P541[天文地球—固体地球物理学]