Seismic images of the continental Moho of the Indian shield
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- 作者：P.R. Reddy ; V. Vijaya Rao
- 关键词：Continental Moho ; Seismic reflection profiling ; Orogeny ; Delamination ; Extension ; Crustal thickness
- 刊名：Tectonophysics
- 出版年：8 December, 2013
- 年：2013
- 卷：609
- 期：Complete
- 页码：217-233
- 全文大小：6793 K
文摘
Deep seismic reflection profiling has imaged different patterns of the Moho across the Indian shield with a variety of tectonic environments from Archean to Recent. The character of the Moho varies from a discrete strong event, the base of strong coherent lower crustal sub-horizontal reflections, the base of dipping lower crustal reflections into mantle, to no clear reflection boundary. The seismic reflection data suggest a laminated lower crust in several places and offsets in the Moho at others. Kinematic and dynamic modeling of wide-angle reflection data across the Mesoproterozoic South Delhi Fold Belt and the Central Indian Tectonic zone suggests a laminated lower crust for these regions. In general, the lower crust of the Indian shield is heterogeneous. A clear Moho is identified in some of the Precambrian orogenic belts and sedimentary basins along with reflective lower-crust, whereas the cratonic areas exhibit a diffused Moho. Post-collisional extensional process, such as orogenic collapse, delamination, magmatic intrusions, low-viscosity ordering and underplating might have played a role in the generation of lower crustal laminated zone and formation of a younger Moho. The termination of lower-crustal reflectivity at the Moho with a transparent upper mantle need not necessarily indicate homogeneous upper mantle.