Basement tectonics and flexural subsidence along western continental margin of India

作     者：D.K.Pandey Nisha Nair Anju Pandey G. Sriram 

作者机构：ESSO-National Centre for Antarctic and Ocean Research Goa India 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2017年第8卷第5期

页      面：1009-1024页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 

基　　金：The authors are thankful to the Director NCAOR for kindly allowing this manuscript to be published.We are also grateful to DGH India for providing us the MCS data for this study.Academic license of seismic interpretation software IHS-KingdomTM is gratefully acknowledged.Authors thank Dr.Alan Roberts and Prof.Nick Kusznir for their help with the FLEX-DECOMPTM package.Ms.Bincy P.K.is acknowledged for preparation of sediment thickness isopach maps.The manuscript benefitted significantly from constructive reviews from anonymous reviewers and the editor.This is NCAOR contribution No.30/2016 

主　　题：Continental rifting Subsidence Mumbai Offshore Basin Backstripping Arabian Sea Laxmi Basin 

摘      要：The Paleocene-recent post-rift subsidence history recorded in the Mumbai Offshore Basin off western continental margin of India is examined. Results obtained through 2-D flexural backstripping modelling of new seismic data reveal considerable thermo-tectonic subsidence over last ca. 56 Myr. Reverse postrift subsidence modelling with variable β stretching factor predicts residual topography of ca. 2000 m to the west of Shelf Margin Basin and fails to restore late Paleocene horizon and the underlying igneous basement to the sea level. This potentially implies that:(1) either the igneous basement formed during the late Cretaceous was emplaced under open marine environs; or(2) a laterally varying cumulative subsidence occurred within Mumbai Offshore Basin(MOB) during ca. 68 to ca. 56 Ma. Pre-depositional topographic variations at ca. 56 Ma across the basin could be attributed to the extensional processes such as varied lower crustal underplating along Western Continental Margin of India(WCMI). Investigations about basement tectonics after unroofing of sediments since late Paleocene from this region support a transitional and heavily stretched nature of crust with high to very high β factors. Computations of past sediment accumulation rates show that the basin sedimentation peaked during late Miocene concurrently with uplift of Himalayan-Tibetan Plateau and intensification of Indian monsoon system. Results from basin subsidence modelling presented here may have significant implications for further studies attempting to explore tectono-climatic interactions in Asia.