Variation in Mantle Transition Zone beneath Central-Tibet

Sharma, Krishn Kant (2019) Variation in Mantle Transition Zone beneath Central-Tibet. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Krishn Kant Sharma (14MS151)) 14MS151.pdf - Submitted Version Restricted to Repository staff only Download (16MB)

Abstract

Topography of the 410 and 660 discontinuities bordering the Mantle Transition Zone provides information on the thickness of the Mantle Transition Zone. This information can help address several geological properties like water content and thermal status of the Mantle Transition Zone and geodynamic questions like genesis of mantle plumes and fate of subducting slabs. To address questions regarding the northern limit of the northward advancement of the Indian slab and as to whether the slab extends to the Bangong–Nujiang Suture (BNS) present in central Tibet, this work has been carried out. In this work, we image the Mantle Transition Zone (MTZ) structure beneath the central Tibet region by applying three-dimensional Common Depth Point (CDP) stacking technique of receiver function for 120 broadband stations of two profiles located in my study area. From this data set, 1614 high-quality receiver functions are generated which are of teleseismic events that have an epicentral distance of 30⁰ to 90⁰ and magnitude greater than 4.5 Mb. Common Depth Point (CDP) stacking of all receiver functions resolves Mantle Transition Zone (MTZ), which appears thicker in the southern Tibet region from 28.5⁰ to 31⁰, mainly due to subduction of the Indian Plate beneath the Tibetan plate. A slight thickening of the Mantle Transition Zone is also observed in central Tibet from 32.5oN to 33.5⁰N mainly due to depression of 660 discontinuity which in turn may be attributed to the presence of mantle lithosphere of the Eurasian Plate.

Actions (login required)

View Item