Nature of the cuvier abyssal plain crust, offshore NW Australia
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Magnetic stripes have long been assumed to be indicative of oceanic crust. However, continental crust heavily intruded by magma can also record magnetic stripes. We re-evaluate the nature of the Cuvier Abyssal Plain (CAP), offshore NW Australia, which hosts magnetic stripes and has previously been defined as oceanic crust. We show that chemical data from a basalt within the CAP, previously described as an enriched mid-ocean ridge basalt, could equally be interpreted to contain evidence of contamination by continental material. We also recognize seaward-dipping reflector sequences in seismic reflection data across the CAP. Borehole data from overlying sedimentary rocks suggests that these seaward-dipping reflectors were emplaced in a shallow water (<200 m depth) or subaerial environment. Our results indicate that the CAP may not be unambiguous oceanic crust, but may instead consist of a spectrum of heavily intruded continental crust through to fully oceanic crust. If the CAP represents such a continent–ocean transition zone, then the adjacent unambiguous oceanic crust would be located >500 km further offshore NW Australia than currently thought. This would impact plate tectonic reconstructions, as well as heat flow and basin modelling studies. Our work also supports the growing consensus that magnetic stripes cannot, by themselves, be used to determine crustal affinity.
Date Issued
2021-04-07
Date Acceptance
2021-03-08
Citation
Journal of the Geological Society, 2021, 178, pp.1-17
ISSN
0016-7649
Publisher
Geological Society of London
Start Page
1
End Page
17
Journal / Book Title
Journal of the Geological Society
Volume
178
Copyright Statement
© 2021 The Author(s). Published by The Geological Society of London. All rights reserved.
Identifier
https://jgs.lyellcollection.org/content/early/2021/04/01/jgs2020-172
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
0403 Geology
0404 Geophysics
0406 Physical Geography and Environmental Geoscience
Geology
Publication Status
Published
Date Publish Online
2021-04-07