How do tectonics influence the initiation and evolution of submarine canyons? A case study from the Otway Basin, SE Australia

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Authors

Nan Wu , Harya Dwi Nugraha , Michael Steventon, Fa Guang Zhong

Abstract

The architecture of canyon-fills can provide a valuable record of the link between tectonics, sedimentation, and depositional processes in submarine settings. We integrate 3D and 2D seismic reflection data to investigate the dominant tectonics and sedimentary processes involved in the formation of two deeply buried (c. 500 m below seafloor), and large (c. 3-6 km wide, >35 km long) Late Miocene submarine canyons. We found the plate tectonic-scale events (i.e. continental breakup and shortening) have a first-order influence on the submarine canyon initiation and evolution. Initially, the Late Cretaceous (c. 65 Ma) separation of Australia and Antarctica resulted in extensional fault systems, which then formed stair-shaped paleo-seabed. This inherited seabed topography allowed gravity-driven processes (i.e. turbidity currents and mass-transport complexes) to occur. Subsequently, the Late Miocene (c. 5 Ma) collision of Australia and Eurasia, and the resulting uplift and exhumation, have resulted in a prominent unconformity surface that coincides with the base of the canyons. We suggest that the Late Miocene intensive tectonics and associated seismicity have resulted in instability in the upper slope that consequently gave rise to emplacement of MTCs, initiating the canyons formation. Therefore, we indicate that regional tectonics play a key role in the initiation and development of submarine canyons.

DOI

https://doi.org/10.31223/X57043

Subjects

Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Sedimentology

Keywords

submarine canyon, mass-transport complexes, Canyon-fill, Tectonic activity

Dates

Published: 2021-12-18 14:47

Last Updated: 2021-12-19 19:26

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License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

Data Availability (Reason not available):
The data used in this study can be requested from the Geoscience Australia Repository https://www.ga.gov.au/data-pubs. In this study we used OS02 3D survey and OS02 2D survey. The GEBCO_2014 bathymetry map is downloaded from https://www.ngdc.noaa.gov/maps/autogrid/.

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