Department of Geology, University of Illinois at Urbana-Champaign, Champaign, IL 61820.
Department of Geology, University of Illinois at Urbana-Champaign, Champaign, IL 61820;
Proc Natl Acad Sci U S A. 2018 Aug 14;115(33):8296-8300. doi: 10.1073/pnas.1717258115. Epub 2018 Jul 30.
What happened to the Indian mantle lithosphere (IML) during the Indian-Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least four pieces with different angles and northern limits, shallower and extending further in the west and east sides while steeper in the middle. Intermediate-depth earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for Late Miocene and Quaternary rifting, current crustal deformation, and intermediate-depth earthquakes in the southern and central Tibetan Plateau and suggests that the deformations of the crust and the mantle lithosphere are strongly coupled.
在印度-欧亚大陆碰撞过程中,印度地幔岩石圈(IML)发生了什么变化,以及它在高原生长中扮演了什么角色,这些都是尚未得到解答的基本问题。在这里,我们从高分辨率 P 和 S 层析成像中显示了 IML 的清晰图像,这表明俯冲的 IML 被撕裂成至少四个不同角度和北界的部分,在西侧和东侧更浅且延伸更远,而在中间则更陡峭。中下地壳和地幔中的中深地震几乎完全位于印度岩石圈的高速(可能较强)部分。IML 的撕裂为中新世晚期和第四纪裂谷作用、当前地壳变形以及青藏高原南部和中部的中深地震提供了一个统一的机制,并表明地壳和地幔岩石圈的变形是强烈耦合的。