Crustal thickness (H) and Vp/Vs ratio (kappa) images beneath the central Tien Shan revealed by the H-kappa-c method
Crustal thickness (H) and Vp/Vs ratio (kappa) images beneath the central Tien Shan revealed by the H-kappa-c method
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H-kappa-c 方法揭示的天山中部下方地壳厚度 (H) 和 Vp/Vs 比 (kappa) 图像
DOI：
10.1016/j.tecto.2021.229157
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发表时间：
2022
期刊：
影响因子：
2.9
通讯作者：
Ran Cui
中科院分区：
文献类型：
--
作者：
Qinghui Cui;Yuanze Zhou;Jiangtao Li;Xiaodong Song;Yuan Gao;Ran Cui
天山作为印度-欧亚大陆碰撞远场影响下的活动陆内造山带，是研究大规模造山机制的天然实验室。本文利用H-κ-c方法，对P波接收函数中的P波及其地壳多次波（PpPs，Ppss+PsPs）进行谐波校正，得到了天山中段地壳地震结构的图像。RF是根据位于天山中部及周边地区的43个宽带台站记录的三分量地震图计算的。最终获得了高分辨率的地壳厚度（H）和平均Vp/Vs比（κ）图像。天山中部地壳厚度（50 ~ 65 km）大于哈萨克地盾（~45 km）和塔里木盆地（~42 km）。κ图像表明，天山中部大部分地区、哈萨克地盾边缘和塔里木盆地的κ值大于1.73，只有个别地区低于1.73。我们的地震结果表明，造山过程中存在复杂的陆内碰撞和地壳不均匀加厚。此外，κ图像暗示了天山中部地壳内部的部分熔融。结合前人的地震研究，我们推测热上涌地幔物质的岩浆侵入导致了地壳内部的部分熔融，也有助于天山造山带的再生。
As an active intracontinental orogenic belt within the far field influence of the India-Eurasia collision, the Tien Shan is a natural laboratory to study the mechanisms of the large-scale mountain building. In this study, we image crustal seismic structures beneath the central Tien Shan using theH-κ-cmethod with the harmonic corrections onPsand its crustal multiples (PpPs,PpSs+PsPs) inP-wave receiver functions (RFs). The RFs are calculated from three-component seismograms recorded by 43 broadband stations located in central Tien Shan and surrounding areas. The robust and high-resolution images of the crustal thickness (H) and averageVp/Vsratio (κ) are finally obtained. From our observations, the crustal thickness beneath the central Tien Shan is larger (50– 65 km) than those beneath the Kazakh Shield (~45 km) and Tarim Basin (~42 km). Theκimage denotes a general distribution ofκwhich is higher than 1.73 in most parts of the central Tien Shan, as well as the margins of the Kazakh Shield and Tarim Basin, while lower than 1.73 only in some sporadic areas of this orogenic belt. Our seismic results suggest the complex intracontinental collision with the inhomogeneous crustal thickening in the mountain building. Moreover, theκimage implies the partial melting within the crust beneath the central Tien Shan. Combining with previous seismic studies, we infer that the magmatic intrusion of the hot upwelling mantle materials induces the partial melts within the crust, and also contributes to the rejuvenation of the Tien Shan orogenic belt.