India-Elan Bank-East Antarctica Breakup, Crustal Architecture, and Margin Evolution: Results From Constrained Potential Field and Process-Oriented Gravity Modeling of Conjugate Margin Segments

Abstract

We present here the results of a seismically well-constrained potential field modeling along with process-oriented gravity modeling across the eastern continental margin of india (ecmi) and its conjugate east antarctica continental margin (eacm). The study revealed both along-strike variations in crustal architecture and effective elastic thickness (te), showing a locally asymmetric pattern. Crustal stretching factors (β) estimated at these margins range between 1.5 and 4.0 with slightly lower values varying over the narrow zone in the cauvery basin-western enderby basin and relatively higher values in other margin segments. The models reveal typical magma-poor margin characteristics in the krishna-godavari (k-g) and cauvery basin segments of ecmi. The ocean-continent transition (oct) in the k-g basin and its conjugate (central enderby basin) indicates asymmetric rifting marked by the development of a detachment fault separating the combined india-elan bank margin and the eacm. The higher β values and magmatic underplating at oct in the mahanadi basin segment of ecmi may be related to the post-breakup magmatic emplacement associated with the proximal activity of the kerguelen plume after the separation of elan bank from india by a ridge jump during m2/m0 (124–120 ma). The pre-rift reconstruction model through the palinspastic restoration of margins suggests that the central part of ecmi (16–20°) is the ideal pre-rift location for the elan bank. © 2021. American geophysical union. All rights reserved.