利用接收函数方法研究华北克拉通中西部及其邻区地幔转换带结构  

Structure of the mantle transition zone beneath the central and western North China Craton and its adjacent areas revealed by P wave receiver functions

作　　者：徐小明[1] 吕苗苗[1] 丁志峰[1] Xu Xiaoming;Lü Miaomiao;Ding Zhifeng(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地震学报》2020年第6期645-656,I0001,共13页Acta Seismologica Sinica

基　　金：国家自然科学基金面上项目(41974100);国家自然科学基金金青年基金(41904093,41604074)共同资助;中国地震局地球物理研究所基本科研业务费专项(DQJB19B18,DQJB16A03,DQJB17A01)。

摘　　要：通过处理Chin Array计划二期和三期台阵中823个台站的远震波形数据,共获得174 562个高质量的P波接收函数,采用接收函数共转换点(CCP)叠加方法开展华北克拉通中西部及其邻区的地幔转换带结构研究,获得了研究区地幔转换带的厚度分布。结果表明:研究区内地幔转换带厚度变化幅值在235—280 km范围内,具有分区特征;阿尔金断裂带东部和汉诺坝火山以北厚的转换带异常可能与冷的岩石圈拆沉有关;河套盆地和阴山造山带附近分布着相对薄的地幔转换带,这可能暗示了该地区存在热的地幔物质上涌或岩浆活动;渤海湾盆地下方厚的地幔转换带异常可能是冷的太平洋板片西向俯冲并滞留于地幔转换带所致。We obtained a total of 174 562 high quality P wave receiver functions by processing the teleseismic waveform data recorded by 823 temporary seismic stations of Chin Array phaseⅡ and Ⅲ deployments,and then used the receiver function common conversion point(CCP)stacking method to study the structure of the mantle transition zone beneath the central and western North China Craton and its adjacent areas. The estimated thickness of the mantle transition zone in this studied area varies from 235 km to 280 km and shows partitioned characteristics.The thick mantle transition zones beneath the eastern Altyn Tagh fault belt and the northern Hannuoba volcano may be related to the detachment of the cold lithosphere. The mantle transition zones beneath the Hetao basin and the Yinshan orogenic belt are thinner than the average of the global mantle transition zone,which maybe imply the upwelling of the hot mantle materials or magma activities. The anomaly of the thicker mantle transition zone beneath the Bohai Bay basin may be caused by the westward subduction of the cold Pacific plate and its remaining in the mantle transition zone.

关 键 词：华北克拉通 接收函数 间断面 地幔转换带厚度 

分 类 号：P315.63[天文地球—地震学]