Jackson, CAL, Magee, C orcid.org/0000-0001-9836-2365 and Hunt-Stewart, ER (2019) Cenozoic Contourites in the Eastern Great Australian Bight, Offshore Southern Australia: Implications For the Onset of the Leeuwin Current. Journal of Sedimentary Research, 89 (3). pp. 199-206. ISSN 1527-1404
Abstract
Thermohaline oceanic currents influence global heat transfer, controlling local and global variations in climate, biodiversity, and the terrestrial biosphere. Paleoceanographic studies typically use biostratigraphic and geochemical proxies to reconstruct the dynamics of these currents in Earth's ancient oceans, although seismic reflection data have also been successfully employed, most commonly in the North Atlantic Ocean. Here we use 2D seismic reflection data from the Ceduna Sub-basin, Great Australian Bight, offshore southern Australia, to describe middle Eocene to Recent contourites deposited in an overall carbonate-dominated succession. These deposits comprise large (100 m wavelength by up to 50 m tall) bedforms and deep (10–90 m), wide (up to 3 km) erosional scours. The scours are particularly well developed at one specific stratigraphic level, defining moats that encircle middle Eocene shield volcanoes, which formed syndepositional bathymetric highs. We suggest that sediment erosion, transport, and deposition record middle Eocene initiation of the Leeuwin Current, one of the most important ocean currents in the southern hemisphere. Deepest seabed scouring occurs in the middle of the middle Eocene to Recent sequence, and may reflect middle Miocene waxing of the so-called “proto-Leeuwin Current,” possibly driven by changes in ocean circulation patterns caused by the Miocene Global Optimum. The results of this seismic reflection-based study are consistent with results derived from other paleoceanographic proxies, thereby highlighting the continued key role seismic reflection data have in understanding the occurrence, geographical distribution, and significance of ancient ocean currents.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This article is protected by copyright. This is an author produced version of a paper published in Journal of Sedimentary Research. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Australia; carbonate rocks; Eocene; Australasia; Indian Ocean; Cenozoic; contourite; geophysical methods; Great Australian Bight; middle Eocene; ocean circulation; South Australia; Tertiary; sedimentary rocks; Paleogene |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 19 Dec 2018 14:50 |
Last Modified: | 12 Mar 2020 01:38 |
Status: | Published |
Publisher: | SEPM Society for Sedimentary Geology |
Identification Number: | 10.2110/jsr.2019.16 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:140160 |