Seafloor Bathymetry of Perth Canyon Marine Park

Bathymetry flythrough of Perth Canyon using data acquired by Schmidt Ocean Institute in 2015 on RV Falkor (University of Western Australia et al.). The flythrough highlights geomorphic features mapped by Geoscience Australia, including landslides, escarpments and bedform fields and biodiversity associated with the canyon (benthic and pelagic). Produced as a science communication product for the Marine Biodiversity Hub (National Environmental Science Program). This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.

Elizabeth and Middleton Reef bathymetry survey (GA4848)

This resource includes bathymetry data for Elizabeth and Middleton Reef within Lord Howe Marine Park collected by Geoscience Australia during the period 31 January to 6 February 2020 on the Australian Maritime College vessel, TV Bluefin. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with the Institute for Marine & Antarctic Studies (University of Tasmania), NSW Department of Primary Industries, University of Sydney (Centre for Field Robotics) and Parks Australia. The purpose of the survey was to collect baseline information for benthic habitats within the National Park Zone (Middleton Reef) and Recreational Use Zone (Elizabeth Reef) of the marine park. These data will support ongoing environmental monitoring within the Temperate East Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included seabed mapping using multibeam sonar (Kongsberg EM 2040C HD, 300 kHz), seabed imagery acquisition by Autonomous Underwater Vehicle (AUV Sirius), sediment samples (grab) and imagery of demersal fish communities by baited remote underwater video (BRUV). This dataset comprises two bathymetry grids derived from multibeam sonar data gridded at 5 m spatial resolution, covering a combined area of 312 km2 including the transit. A detailed report on the survey is provided in: Carroll, A et al. 2020. Australian Marine Park Baseline and Monitoring Survey: Post Survey Report, Middleton and Elizabeth Reefs, Lord Howe Marine Park. Report to the National Environmental Science Program, Marine Biodiversity Hub. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia

SA DEWNR - South Australian Marine Bathymetry and Side Scan Sonar [for NESP D3]

Bathymetry and Side Scan Sonar transects taken in various project locations within South Australian state waters. For analysis of seabed topography and interpretation of benthic substrate and flora.

Beagle Marine Park backscatter data 2018

This resource includes multibeam sonar backscatter data for Beagle Marine Park (Bass Strait) collected by Geoscience Australia (GA) and the Institute for Marine & Antarctic Studies (University of Tasmania; UTAS) during the period 17 – 26 June 2018 on the RV Bluefin. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with co-investment by GA and UTAS. The purpose of the project was to build baseline information for benthic habitats in the Beagle Marine Park that will support ongoing environmental monitoring within the South-east Marine Park Network as part of the 10-year management plan (2013-2023). Data acquisition for the project was completed during three separate voyages: Phase 1 - Seabed mapping by multibeam sonar; Phase 2 – Seabed imagery acquisition by Autonomous Underwater Vehicle, and sediment sampling; Phase 3 – Survey of demersal fish communities using Baited Remote Underwater Video (BRUVs). This dataset from Phase 1 comprises 11 backscatter grids derived from multibeam sonar data gridded at 1 m spatial resolution, covering a combined area of 364 km2. A detailed report on the survey is provided in: Falster, G., Monk, J., Carroll, A., Siwabessy, J., Deane, A., Picard, K., Dando, N., Hulls, J., Nichol, S., Barrett, N. 2019. Australian Marine Park Baseline and Monitoring Survey: Post Survey Report, Beagle Marine Park, South-east Marine Park Network. Report to the National Environmental Science Program, Marine Biodiversity Hub.

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

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.

High-resolution global bathymetry grids for key Cretaceous and early Cenozoic climate stages

Ocean currents are strongly controlled by seafloor topography. Recent studies have shown that small-scale features with slopes steeper than 0.05° significantly affect subsurface eddy velocities and the vertical structure of ocean circulation patterns. Such slope gradients represent the majority of the present-day oceanic basins. Modeling past oceanographic conditions for key climate stages requires similarly detailed paleo seafloor topography grids, in order to capture ocean currents accurately, especially for ocean models with sufficient resolution (<0.1°) to resolve eddies. However, existing paleobathymetry reconstructions use either a forward modeling approach, resulting in global grids lacking detailed seafloor roughness, or a backward modeling technique based on sediment backstripping, capturing realistic slope gradients, but for a spatially restricted area. Both approaches produce insufficient boundary conditions for high-resolution global paleo models. Here, we compute high-resolution global paleobathymetry grids, with detailed focus on the Southern Ocean, for key Cretaceous and early Cenozoic climate stages. We backstrip sediments from the modern global bathymetry, allowing the preservation of present-day seafloor slope gradients. Sediment isopach data are compiled from existing seismo-stratigraphic interpretations along the Southern Ocean margins, and expanded globally using total sediment thickness information and constant sedimentation rates. We also consider the effect of mantle flow on long-wavelength topography. The resulting grids contain realistic seafloor slope gradients and continental slopes across the continent-ocean transition zones that are similar to present-day observations. Using these detailed paleobathymetry grids for high-resolution global paleo models will help to accurately reconstruct oceanographic conditions of key climate stages and their interaction with the evolving seafloor.

A Nationally Consistent Geomorphic Classification of the Australian Coastal Zone

Geoscience Australia has completed the first phase of an areal map of Australia's coastal geomorphological units. Utilising pre-existing GIS datasets procured from local, state and federal government agencies, this national scale map conforms to a coastal geomorphology classification scheme developed at Geoscience Australia. Phase one consists of a geodatabase containing a series of state wide feature datasets that have been reclassified into the national coastal geomorphology classification scheme.

Elizabeth and Middleton Reef multibeam sonar backscatter survey (GA4848)

This resource includes multibeam sonar backscatter data for Middleton Reef and Elizabeth Reef within Lord Howe Marine Park collected by Geoscience Australia during the period 31 January to 6 February 2020 on the Australian Maritime College vessel, TV Bluefin. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with the Institute for Marine & Antarctic Studies (University of Tasmania), NSW Department of Primary Industries, University of Sydney (Australian Centre for Field Robotics) and Parks Australia (Marine Park managers, Commonwealth Government). The purpose of the survey was to collect baseline information for benthic habitats within the National Park Zone (Middleton Reef) and Recreational Use Zone (Elizabeth Reef) of the marine park. These data will support ongoing environmental monitoring within the Temperate East Marine Park Network as part of its 10-year management plan (2018-2028). Data acquisition for the project included seabed mapping using multibeam sonar (Kongsberg EM 2040C HD, 300 kHz), seabed imagery acquisition by Autonomous Underwater Vehicles (AUV Sirius and AUV Nimbus), sediment samples (grab) and imagery of demersal fish communities by baited remote underwater videos (BRUVs). This dataset comprises two bathymetry grids derived from multibeam sonar data gridded at 4 mspatial resolution. A detailed report on the survey is available on the Marine Biodiversity Hub’s website (https://www.nespmarine.edu.au/reports; Carroll, A et al., 2020,. Australian Marine Park Baseline and Monitoring Survey: Post Survey Report, Middleton and Elizabeth Reefs, Lord Howe Marine Park. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia

Marine Futures Project - Abrolhos Islands - reef habitat

The Marine Futures Project was designed to benchmark the current status of key Western Australian marine ecosystems, based on an improved understanding of the relationship between marine habitats, biodiversity and our use of these values. Approximately 1,500 km2 of seafloor were mapped using hydroacoustics (Reson 8101 Multibeam), and expected benthic habitats "ground-truthed" using towed video transects and baited remote underwater video systems. Both sources of information were then combined in a spatial predictive modelling framework to produce fine-scale habitat maps showing the extent of substrate types, biotic formations, etc. Surveys took place across 9 study areas, including the Abrolhos Islands, a group of 122 limestone outcrops surrounded by fringing reed ca. 60km west from the city of Geraldton. The Abrolhos research location is the most northerly of the Marine Futures sampling sites, selected due to the unique mixture of tropical coral reef habitats, and temperate reef and seagrass communities.The hydroacoustics data were processed to construct full coverage maps of bathymetry and textural information.

Predicted seabed gravel, mud and sand content in the Timor Sea region in the Australian continental EEZ 2018

This dataset provides the spatially continuous data of seabed gravel (sediment fraction >2000 µm), mud (sediment fraction < 63 µm) and sand content (sediment fraction 63-2000 µm) expressed as a weight percentage ranging from 0 to 100%, presented in 10 m resolution raster grids format and ascii text file.</p> The dataset covers the eight areas in the Timor Sea region in the Australian continental EEZ.</p> This dataset supersedes previous predictions of sediment gravel, mud and sand content for the basin with demonstrated improvements in accuracy. Accuracy of predictions varies with sediment types, with a VEcv = 71% for mud, VEcv = 72% sand and VEcv = 42% for gravel. Artefacts occur in this dataset as a result of noises associated predictive variables (e.g., horizontal and vertical lines resulted from predictive variables derived from backscatter data are the most apparent ones). To obtain the most accurate interpretation of sediment distribution in these areas, it is recommended that noises with backscatter data should be reduced and predictions updated.</p> This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.

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