中国东部地区的壳-幔过渡带结构  

The crust-mantle transition structures beneath eastern China

作　　者：孙伟家[1,2] 符力耘 魏伟[2,4] 林羿 唐清雅[1,2] SUN WeiJia1,2 , FU LiYun1,3 , WEI Wei4,2 , LIN Yi1,2 , TANG QingYa1,2 1 Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics Chinese Academy of Sciences, Beijing 100029, China 2 Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China 3 School of Geosciences, China University of Petroleum(East China）, Shandong Qingdao 266580, China 4 Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, Chin)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院地球与行星物理重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [4]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029

出　　处：《地球物理学报》2018年第3期845-855,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41720104006,41630210)和中国科学院青年创新促进会(2017094)联合资助.

摘　　要：莫霍面是地壳和上地幔的边界,但莫霍面并不是一个简单的"面",而是一个反映地壳和地幔物质交换、相互作用等动力学意义的"过渡带".本文综合深地震反射、宽角地震折射和高温高压岩石物理实验结果,确定壳-幔过渡带的地震P波速度变化范围为6.8~7.5km·s-1.在克拉通等构造活动稳定地区壳-幔过渡带内的速度梯度强且壳-幔过渡带厚度薄,而在造山带等构造活动区域壳-幔过渡带内的速度梯度弱且壳-幔过渡带厚.中国东部地区的壳-幔过渡带的平均厚度约为5~10km,在四川盆地下方最薄(<5km),而在华北克拉通中部造山带下方的壳-幔过渡带最厚(~30km).综合地球化学结果,华北中部巨厚壳-幔过渡带主要是幔源岩浆的底侵作用和堆晶作用而形成.The Moho is a discontinuity separating the crust from the mantle. However, the Moho cannot be simply represented by a sharp discontinuity but a transition with thickness ranging from several kilometers to tens of kilometers. The transition could reveal the interactions between the crust and the mantle. Combining the results of deep seismic sounding, wide-angle seismic refractions and high-temperature high-pressure experiments, the paper determines the range of P wave speed of the crust-mantle transition to be 6.8-7.5 km · s-1. The mean thickness of the crust-mantle transition is 5-10 km beneath eastern China. The thinnest crust-mantle transition occurs beneath Sichuan Basin, the core of Yangtze Craton. The crust-mantle transition beneath Trans-North China Orogen （TNCO） is as thick as -30 km. With geochemical evidences, the thick crust-mantle transition might be attributed to underplating and accumulation of mantle magma.

关 键 词：壳-幔过渡带 地震波传播 层析反演 地震光照成像 底侵作用 

分 类 号：P315[天文地球—地震学]