Tectonic and oceanographic process interactions archived in the Late Cretaceous to Present deep-marine stratigraphy on the Exmouth Plateau, offshore NW Australia
File(s)
Accepted version
Author(s)
Nugraha, Harya
Jackson, Christopher
Johnson, Howard
Hodgson, David
Reeve, Matthew
Type
Journal Article
Abstract
Deep-marine deposits provide a valuable archive of process interactions between sediment gravity flows, pelagic sedimentation, and thermo-haline bottom-currents. Stratigraphic successions can also record plate-scale tectonic processes (e.g. continental breakup and shortening) that impact long-term ocean circulation patterns, including changes in climate and biodiversity. One such setting is the Exmouth Plateau, offshore NW Australia, which has been a relatively stable, fine-grained carbonate-dominated continental margin from the Late Cretaceous to Present. We combine extensive 2D (~40,000 km) and 3D (3,627 km2) seismic reflection data with lithologic and biostratigraphic information from wells to reconstruct the tectonic and oceanographic evolution of this margin. We identified three large-scale seismic units (SUs): (1) SU-1 (Late Cretaceous) – 500 m-thick, and characterised by NE-SW-trending, slope-normal elongate depocentres (c. 200 km long and 70 km wide), with erosional surfaces at their bases and tops, which are interpreted as the result of contour-parallel bottom-currents, coeval with the onset of opening of the Southern Ocean; (2) SU-2 (Palaeocene – Late Miocene) – 800 m-thick and characterised by: (i) very large (amplitude, c. 40 m and wavelength, c. 3 km), SW-migrating, NW-SE-trending sediment waves, (ii) large (4 km-wide, 100 m-deep), NE-trending scours that flank the sediment waves, and (iii) NW-trending, 4 km wide and 80 m deep turbidite channel, infilled by NE-dipping reflectors, which together may reflect an intensification of NE-flowing bottom currents during a relative sea-level fall following the establishment of circumpolar-ocean current around Antarctica; and (3) SU-3 (Late Miocene – Present) – 1000 m-thick and is dominated by large (up to 100 km3) mass-transport complexes (MTCs) derived from the continental margin (to the east) and the Exmouth Plateau Arch (to the west), and accumulated mainly in the adjacent Kangaroo Syncline. This change in depositional style may be linked to tectonically-induced seabed tilting and folding caused by collision and subduction along the northern margin of the Australian plate. Hence, the stratigraphic record of the Exmouth Plateau provides a rich archive of plate-scale regional geological events occurring along the distant southern (2000 km away) and northern (1500 km away) margins of the Australian plate.
Date Issued
2019-06
Date Acceptance
2018-11-06
Citation
Basin Research, 2019, 31 (3), pp.405-430
ISSN
0950-091X
Publisher
Wiley
Start Page
405
End Page
430
Journal / Book Title
Basin Research
Volume
31
Issue
3
Copyright Statement
© 2018 The Authors. Basin Research © 2018 International Association of Sedimentologists and European Association of Geoscientists and Engineers and John Wiley & Sons Ltd. This is the pre-peer reviewed version of the following article, which has been published in final form at https://onlinelibrary.wiley.com/doi/full/10.1111/bre.12328
Identifier
https://onlinelibrary.wiley.com/doi/10.1111/bre.12328
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
bottom current
contourites
deep marine
Exmouth Plateau
MTCs
NW Australia
palaeo-oceanography
seismic reflection
tectonics and sedimentation
MASS-TRANSPORT COMPLEXES
CURRENT-CONTROLLED SEDIMENTATION
CONTOURITE DEPOSITIONAL SYSTEM
GIANT SUBMARINE LANDSLIDE
SANTA-MONICA BASIN
NORTH-WEST SHELF
ANTARCTIC PENINSULA
CONTINENTAL-MARGIN
BOTTOM CURRENTS
LEEUWIN CURRENT
04 Earth Sciences
Geology
Publication Status
Published
Date Publish Online
2018-11-12