远震P波接收函数揭示的张家口(怀来)-中蒙边境(巴音温多尔)剖面地壳厚度与泊松比  

Crustal thickness and Poisson ratio beneath the Huailai-Bayinonder profile derived from teleseismic receiver functions

作　　者：龚辰[1] 李秋生[1] 叶卓[1] 张洪双[1] 李文辉[1] 贺传松[2] 李英康[3] 

机构地区：[1]中国地质科学院地质研究所,国土资源部“深部探测与地球动力学”重点实验室,北京100037 [2]中国地震局地球物理研究所,北京100081 [3]国土资源实物地质资料中心,河北燕郊065201

出　　处：《地球物理学报》2016年第3期897-911,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41174081);“深部探测技术与实验研究”专项(Sinoprobe-02-03,公益科研专项项目编号201311156)联合资助

摘　　要：本文使用时间域迭代反褶积算法,从张家口(怀来)—巴音温多尔一线布设的41个宽频地震台站、1年期间记录的连续三分量数据中提取到高质量的P波接收函数1844个.用H-κ扫描方法获得了测线下方Moho深度与波速比值(VP/VS)进而计算出泊松比,用共转换点(CCP)叠加方法获得了沿测线Moho面起伏图像.结果显示:(1)测线下方Moho深度平均40km,仅各块体边界处出现Moho深度小尺度急剧变化.整体上,Moho面产状相对于索伦缝合带大致对称,在缝合带南侧的温都尔庙带和白乃庙带下方呈南倾趋势,在缝合带北侧的宝力道带、贺根山杂岩带下方呈北倾趋势.(2)华北克拉通北缘泊松比总体较高,兴蒙造山带整体较低;各次级块体内部泊松比分布相对稳定,块体分界带附近往往存在泊松比值的升降扰动.(3)整条测线地壳厚度和泊松比之间存在弱的负相关关系,表明存在构造作用的影响.(4)整条测线泊松比呈现以索伦缝合带南缘为对称轴的非线性分布.本文所获得的地壳上地幔结构以及泊松比分布特征,支持古亚洲(索伦)洋(南北)双向俯冲,最终沿林西断裂闭合的动力学模式.The Central Asian Orogenic Belt（CAOB）between the Siberia paleo-continent and the North China paleo-continent has a close relationship with the evolution of the Paleo-Asian Ocean.The Xing′an-Mongolia Orogenic Belt（XMOB）as eastern part of the CAOB is located in NorthChina.It is generally considered that the closure of the Paleo-Asian Ocean resulted in the formation of the XMOB,but there remain some disputes about the tectonic attribute of the northern margin of the North China Craton and where the Paleo-Asian Ocean finally closed and how it behaves due to complex evolution process,extensive coverage of Cenozoic sediments and the lack of high resolution deep exploration data.Structures and some major discontinuities beneath stations can be imaged by the receiver function method.In recent years,this method has become a mature and effective tool for studying the velocity structure of the crust and upper mantle.By the H-κstacking method,the P-to-S converted waves at the Moho discontinuity and their multiple reflections are used to calculate crust thickness and VP/VSratio,which provide a way to study the rock composition of the crust and stress condition under stations.Funded by National Natural Science Foundation of China,Institute of Geology,Chinese Academy of Geological Sciences deployed 41 portable broadband seismic stations from Huailai county in northern North China to Bayinondor town near the China-Mongolia border.The profile extends along the reflection and refraction profile funded by Sinoprobe project,crossing the Yinshan-Yanshan orogenic belt,the Inner Mongolia paleo-uplift,the Bainaimiao arc,the Ondor sum subduction accretion complex,the Solonker suture zone（the Solonder suture zone,located between the North China plate and Siberia plate,representing the closure of the Paleo-Asian Ocean）,the Baolidao arc accretion complex,the Hegenshan ophiolite arc accretion complex and the Uliastai active continental margin from south to north.Recorders were set to the continuous recording mode and the sampl

关 键 词：兴蒙造山带 古亚洲洋 接收函数 地壳上地幔结构 泊松比 

分 类 号：P315[天文地球—地震学]