华北东部复杂的660km相变界面

发布时间：2018-01-18 03:22

本文关键词：华北东部复杂的660km相变界面　出处：《地球物理学报》2016年06期 　论文类型：期刊论文

【摘要】：利用华北固定台网的宽频带地震远震记录波形资料,提取P波接收函数,通过偏移成像和共转换点叠加,得到华北地区东部地幔过渡带深度及厚度的图像.研究结果显示,地幔过渡带上界面(410km间断面)深度起伏变化不大;在华北地区东部,存在较厚的地幔过渡带,地幔过渡带下界面(660km间断面)在660km深度附近出现两个不同的界面.造成地幔过渡带增厚并出现两个深度不同的界面的原因可能是存在橄榄岩以外的地幔物质相变,该物质相变拥有与橄榄岩向钙钛矿转变不同的克拉伯龙斜率,太平洋俯冲板块的低温造成两种不同的相变界面发生不同程度的改变.双重660km间断面的范围存在向北西方向延伸的趋势并且向南至少延伸到30°N.本文的结果可为古西太平洋板块向华北俯冲前缘位置的研究提供约束.
[Abstract]:Using the waveform data of broadband seismic remote seismicity recorded in North China fixed network, the P-wave receiving function is extracted, and then the migration imaging and common-conversion point stack are used. The depth and thickness of the mantle transition zone in the eastern part of North China are obtained. The results show that the depth fluctuation of the mantle transition zone is not changed much. In the eastern part of North China, there is a thick mantle transition zone. The interfacial section between 660km and 660km below the mantle transition zone). There are two different interfaces near the 660km depth. The reason for the thickening of the mantle transition zone and the formation of two interfaces with different depths may be the existence of mantle material phase transition other than peridotite. The material phase transition has a different clabron slope from peridotite to perovskite. The low temperature of the Pacific subduction plate results in the change of two different phase transition interfaces in different degrees. The range of the double 660km discontinuities tends to extend northwestward and south to at least 30 掳N. The results of this paper can provide constraints for the study of the position of the paleo-western Pacific plate subducting to North China.
【作者单位】：中国科学院地质与地球物理研究所;中国科学院大学;
【基金】：中科院先导性专项(B)(XDB03010700) 国家自然科学基金项目(41274066) 地震局行业科研专项(201408023)联合资助
【分类号】：P315.2
【正文快照】： 1引言华北地区位于菲律宾板块和太平洋板块向欧亚板块俯冲的俯冲带附近,板块的俯冲作用一直被认为是导致华北克拉通破坏的重要因素(Wu et al.,2005;朱日祥等,2011,2012).臧绍先和宁杰远(1996)认为菲律宾板块向欧亚板块俯冲的最大深度不超过250km;Huang等(2013)利用3-D层析成像

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