The breakup of East Gondwana: Assimilating constraints from Cretaceous ocean basins around India into a best-fit tectonic model

Published models for the Cretaceous sea!oor-spreading history of East Gondwanaresult in unlikely tectonic scenarios for at least one of the plate boundaries involved and/orviolate particular constraints from at least one of the associated ocean basins. We link EastGondwana spreading corridors by int...

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Bibliographic Details
Published in:Journal of Geophysical Research: Solid Earth
Main Authors: Gibbons, AD, Whittaker, JM, Muller, RD
Format: Article in Journal/Newspaper
Language:English
Published: Wiley-Blackwell Publishing Inc. 2013
Subjects:
Earth Sciences
Geology
Marine Geoscience
Conrad Rise
East Antarctica
East Ridge
Elan Bank
Kerguelen
Wharton
Antarc*
Antarctica
Online Access:https://doi.org/10.1002/jgrb.50079
http://ecite.utas.edu.au/84430
Description
Summary:Published models for the Cretaceous sea!oor-spreading history of East Gondwanaresult in unlikely tectonic scenarios for at least one of the plate boundaries involved and/orviolate particular constraints from at least one of the associated ocean basins. We link EastGondwana spreading corridors by integrating magnetic and gravity anomaly data from theEnderby Basin off East Antarctica within a regional plate kinematic framework to identify aconjugate series of east-west-trending magnetic anomalies, M4 to M0 (~126.7120.4 Ma).The mid-ocean ridge that separated Greater India from Australia-Antarctica propagatedfrom north to south, starting at ~136Ma northwest of Australia, and reached the southern tipof India at ~126 Ma. Sea!oor spreading in the Enderby Basin was abandoned at ~115 Ma,when a ridge jump transferred the Elan Bank and South Kerguelen Plateau to the Antarcticplate. Our revised plate kinematic model helps resolve the problem of successive two-waystrike-slip motion between Madagascar and India seen in many previously publishedreconstructions and also suggests that sea!oor spreading between them progressed fromsouth to north from 94 to 84 Ma. This timing is essential for tectonic !ow lines to match thecurved fracture zones of the Wharton and Enderby basins, as Greater India gradually beganto unzip from Madagascar from ~100 Ma. In our model, the 85-East Ridge and KerguelenFracture Zone formed as conjugate !anks of a leaky transform fault following the~100Ma spreading reorganization. Our model also identi"es the Afanasy NikitinSeamounts as products of the Conrad Rise hotspot.

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