Poster Presentation Australian Marine Sciences Association 2026 Conference

Investigations of the South-Western Tasmanian and the Eastern Australian Continental Margins: their similarities and differences provide insights into the processes controlling their evolution and modification. (138796)

Thomas C Hubble 1 , Hannah E Power 2 , Micheal Kinsela 2 , Elise Buller 2 , Kendall Mollison 2 , Bronwyn Davies 3 , Robert De Lastic 3 , David Airey 4 , Shipboard Parties 5
  1. School of Geosciences, The University of Sydney, Sydney, NSW, Australia
  2. School of Life and Environmental Sciences , The University of Newcastle, Newcastle, New South Wales, Australia
  3. Seismic Processing and Interpretation, The Rawson Institute, Sydney, NSW, Australia
  4. School of Civil Engineering, The University of Sydney, Sydney, NSW, Australia
  5. Shipboard Parties, RV Investigator (IN2022-V05, IN2023-V02), Hobart , Tasmania, Australia

Research voyages aboard the Australian Marine National Facility vessel RV Investigator in June 2022 and April 2023 (IN2022-V05 and IN2023-V02) investigated geomorphic features associated with large submarine landslides located on the South-Eastern Australian and South-West Tasmanian continental margins. The subtly different geologic histories and oceanographic settings of these two areas have produced similar upper and middle slope morphologies but distinctly different lower-slope and abyssal plain geomorphologies and sediment deposits. Large, Plio-Pleistocene landslide scars and sediment slump features are well-developed on both the South-West Tasmanian and Eastern Australian continental slopes but well-developed landslide debris fields and turbidite deposits obviously associated with these landslide scars are only evident on the lower slope and abyssal plain offshore South-Western Tasmania. In contrast to the numerous geomorphic features and sediment accumulations indicative of mass transport deposits offshore south-western Tasmania, the lower slope and abyssal plain offshore eastern Australia presents features typical of vertical accretion of pelagic sediments and erosional processes. The absence of depositional features but widespread occurrence of pronounced erosion suggests strong bottom current activity has been a major driver controlling the formation of sea-floor morphologic features formation offshore South-Eastern Australia during much of the Quaternary (ie. the last two million years).