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Early India-Australia spreading history revealed by newly detected Mesozoic magnetic anomalies in the Perth Abyssal Plain

Citation

Williams, SE and Whittaker, J and Granot, R and Muller, DR, Early India-Australia spreading history revealed by newly detected Mesozoic magnetic anomalies in the Perth Abyssal Plain, Journal of Geophysical Research - Solid Earth, 118, (7) pp. 3275-3284. ISSN 2169-9313 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 American Geophysical Union

DOI: doi:10.1002/jgrb.50239

Abstract

The seafloor within the Perth Abyssal Plain (PAP), offshoreWestern Australia, is the only section of crust that directly records the early spreading history between India and Australia during the Mesozoic breakup of Gondwana. However, this early spreading has been poorly constrained due to an absence of data, including marine magnetic anomalies and data constraining the crustal nature of key tectonic features. Here, we present new magnetic anomaly data from the PAP that shows that the crust in the western part of the basin was part of the Indian Plate—the conjugate flank to the oceanic crust immediately offshore the Perth margin, Australia. We identify a sequence of M2 and older anomalies in the west PAP within crust that initially moved with the Indian Plate, formed at intermediate half-spreading rates (35 mm/yr) consistent with the conjugate sequence on the Australian Plate. More speculatively, we reinterpret the youngest anomalies in the east PAP, finding that the M0-age crust initially formed on the Indian Plate was transferred to the Australian Plate by a westward jump or propagation of the spreading ridge shortly afterM0 time. Samples dredged from the Gulden Draak and Batavia Knolls (at the western edge of the PAP) reveal that these bathymetric features are continental fragments rather than igneous plateaus related to Broken Ridge. These microcontinents rifted away from Australia with Greater India during initial breakup at ~130Ma, then rifted from India following the cessation of spreading in the PAP (~101–103Ma).

Item Details

Item Type:Refereed Article
Keywords:marine magnetics, tectonics, reconstruction
Research Division:Earth Sciences
Research Group:Geology
Research Field:Tectonics
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Whittaker, J (Dr Jo Whittaker)
ID Code:88443
Year Published:2013
Web of Science® Times Cited:13
Deposited By:IMAS Research and Education Centre
Deposited On:2014-02-03
Last Modified:2014-06-03
Downloads:0

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