A three‐dimensional Moho depth model for the Tien Shan from EGM2008 gravity data
A three‐dimensional Moho depth model for the Tien Shan from EGM2008 gravity data
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DOI：
10.1029/2011tc002886
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发表时间：
2011-10
期刊：
影响因子：
4.2
通讯作者：
R. Steffen;H. Steffen;G. Jentzsch
中科院分区：
文献类型：
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作者：
R. Steffen;H. Steffen;G. Jentzsch
中亚的天山是世界上最大的陆内山脉，但距离印度板块和欧亚板块的碰撞带有1500公里。该地区一直是并且仍然是众多地球科学研究的焦点，主要是因为它的演化历史及其在欧亚岩石圈板块中的独特地位。到目前为止，主要利用地震数据来探索该地区地震活动的起源和持续发生的地震活动，但只有一项研究调查了地球重力数据。在这项研究中，新的重力数据集EGM2008用于通过重力数据反演来确定天山的壳幔边界（莫霍面，莫霍面）。此外，根据地形数据计算等静压莫霍面，通过与重力反演结果的比较，阐明等静压补偿的效果。重力反演结果与前期地震研究结果基本一致，表明天山有一个厚度约为75公里的山根。此外，莫霍面在盆地下方很浅，例如塔里木盆地和伊犁盆地。与等静压莫霍面的比较表明造山带的过度补偿和盆地的补偿不足。超补偿是塔里木盆地南部地体先前俯冲的结果。塔里木盆地补偿不足是由于北部天山和南部帕米尔高原、西藏和喜马拉雅山之间地体的支撑而产生的。
The Tien Shan in Central Asia is the largest intracontinental mountain range in the world, but it is 1500 km away from the collision zone between the Indian and Eurasian plates. This region has been and still is the focus of numerous geoscientific studies, mainly because of its evolutionary history and its unique position in the Eurasian lithosphere plate. So far, mainly seismological data have been used to explore the origin of and ongoing seismic activity in this region, but only one study has investigated terrestrial gravity data. In this study, a new gravity data set, EGM2008, is used to determine the crust‐mantle boundary (Mohorovičić discontinuity, Moho) of the Tien Shan using inversion of gravity data. In addition, an isostatic Moho is calculated from topographic data, which by comparison to the results of the gravity inversion illuminates the effects of isostatic compensation. The results of the gravity inversion generally agree with results of previous seismic studies and indicate that the Tien Shan has a mountain root with a thickness of about 75 km. Furthermore, the Moho is shallow under the basins, e.g., in the Tarim and Ili basins. The comparison with the isostatic Moho indicates an over‐compensation of the orogen and an under‐compensation of the basins. The over‐compensation results from the former subduction of the Tarim Basin terrane in the south. The under‐compensation of the Tarim Basin is generated by support of the terrane between the Tien Shan in the north and the Pamir mountains, Tibet and Himalayas in the south.