Tectonic, Oceanographic, and Climatic Controls on the Cretaceous-Cenozoic Sedimentary Record of the Australian-Antarctic Basin

• Other Authors: Sauermilch, Isabel (hasPrincipalInvestigator), Sauermilch, Isabel (pointOfContact), Whittaker, Joanne, Assoc/Prof (hasPrincipalInvestigator), Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) (hasAssociationWith)
• Format: Dataset
• Language: unknown
• Published: University of Tasmania, Australia
• Subjects: geoscientificInformation; Australian Antarctic margins; IODP drilling; Cretaceous-Cenozoic; STRATIGRAPHIC SEQUENCE; EARTH SCIENCE; LAND SURFACE; GEOMORPHIC LANDFORMS/PROCESSES; AEOLIAN PROCESSES; SEDIMENTATION; SEDIMENT TRANSPORT; MARINE GEOPHYSICS; OCEANS; PLATE TECTONICS; BOREHOLES; PALEOCLIMATE; LAND RECORDS; SEDIMENT THICKNESS; CLIMATE INDICATORS; PALEOCLIMATE INDICATORS; SEDIMENTS; Marine Geoscience; EARTH SCIENCES; GEOLOGY; Tectonics; Geodynamics; GEOPHYSICS; Sedimentology; Antarctic; The Antarctic; Australian Antarctic Basin; Australian-Antarctic Basin; Antarc*; Antarctica
• Online Access: https://researchdata.edu.au/tectonic-oceanographic-climatic-antarctic-basin/1343718; http://metadata.imas.utas.edu.au:/geonetwork/srv/en/metadata.show?uuid=d0d3b7a0-9ab4-4246-894e-3eb0993b6751

Understanding the patterns and characteristics of sedimentary deposits on the conjugate Australian-Antarctic margins is critical to reveal the Cretaceous-Cenozoic tectonic, oceanographic and climatic conditions in the basin. However, unravelling its evolution has remained difficult due to the different seismic stratigraphic interpretations on each margin and sparse drill sites. Here, for the first time, we collate all available seismic reflection profiles on both margins and use newly available offshore drilling data, to develop a consistent seismic stratigraphic framework across the Australian-Antarctic basins. We find sedimentation patterns similar in structure and thickness, prior to the onset of Antarctic glaciation, enabling the basin-wide correlation of four major sedimentary units and their depositional history. We interpret that during the warm and humid Late Cretaceous (~83-65 Ma), large onshore river systems on both Australia and Antarctica resulted in deltaic sediment deposition offshore. We interpret that the onset of clockwise bottom currents during the Early Paleogene (~58-48 Ma) formed prominent sediment drift deposits along both continental rises. We suggest that these currents strengthened and progressed farther east through the Eocene. Coevally, global cooling (<48 Ma) and progressive aridification led to a large-scale decrease in sediment input from both continents. Two major Eocene hiatuses recovered by the IODP site U1356A at the Antarctic continental slope likely formed during this pre-glacial phase of low sedimentation and strong bottom currents. Our results can be used to constrain future paleo-oceanographic modelling of this region and aid understanding of the oceanographic changes accompanying the transition from a greenhouse to icehouse world. Seismo-stratigraphic boundary layers of key sedimentary supersequences are interpreted, based on multichannel seismic data offshore Australia and Antarctica. The interpreted horizons are exported and used to compute interpolated 0.5° grids in TWT (s). For each key horizon, velocity grids are computed using the interval velocities from in total 1143 sonobuoy and ocean bottom seismometer (OBS) stations (after Whittaker et al., 2013b; Fig. 1a) as a function of TWT. Horizon grids in depth (km), sediment thickness (“isopach”) grids and volumes for each supersequence are calculated and reconstructed back in geological time (Fig. 8 – 67 Ma, Fig. 9 – 43.8 Ma) using GPlates 2.0 and the plate model of Matthews et al. (2016).