Using large dynamite shots to image the structure of the Moho from deep seismic reflection experiment between the Sichuan basin and Qinling orogen

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• 作者：Hongqiang Li ; Rui Gao ; Haiyan Wang ; Wenhui Li ; Xiaosong Xiong
• 关键词：Moho ; Deep seismic reflection profiles ; Large dynamite shots ; Qinling Orogen ; China
• 刊名：Earthquake Science
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：29
• 期：6
• 页码：321-326
• 全文大小：1751KB
• 刊物主题：Geophysics/Geodesy;
• 出版者：Seismological Society of China
• ISSN：1867-8777
• 卷排序：29

文摘

The Qinling orogen was formed as a result of the collision between the North and South China blocks. The Qinling orogen represents the location at which the southern and northern parts of the Chinese mainland collided, and it’s also the intersection of the Central China orogen and the north-south tectonic belt. There is evidence of strong deformation in this orogen, and it has had a long and complex geological history. We investigated the structure of the Moho in the southern Qinling orogen using large dynamite shot imaging techniques. By integrating the analysis of the single-shot and the move-out corrections profile, we determined the structure of the Moho beneath the northern Dabashan thrust belt and the southern Qinling orogen, including the mantle suture beneath Fenghuang mountain. The Moho is divided into two parts by the mantle suture zone beneath Fenghuang mountain: (1) from Ziyang to Hanyin, the north-dipping Moho is at about 45–55 km depth and the depth increases rapidly; and (2) from Hanyin to Ningshan, the south-dipping Moho is at about 40–45 km depth and shallows slowly. The mantle suture is located beneath Fenghuang mountain, and the Moho overlaps at this location: the shallower Moho is connected to the northern part of China, and the deeper Moho is connected to the southern part. This may indicate that the lithosphere in the Sichuan basin subducts to the Qinling block and that the subduction frontier reaches at least as far as Fenghuang mountain.