CONTINENTAL MARGINS
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This record includes datasets pertaining to the appendix of Jeremy Asimus' thesis. This includes: Appendix A: Unpublished major, trace element and Sr-Nd-Pb-Hf isotope analyses from volcanic and continental rocks dredged at Gulden Draak Rise, Batavia Rise, Dirk Hartog Ridge and the Naturaliste Plateau within the Perth Abyssal Plain. These rocks were collected by the Southern Surveyor (SS2011_V06 voyage and SS2005_V09). Appendix B: Unpublished monazite U-Pb geochronology results from a metapelite (D03_002) at Rig Seismic Seamount. This metapelite was collected by the RV Investigator.
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The final lithospheric breakup of the Australian-Antarctic rift system remains controversial due to sparse geological constraints on the nature of the basement along the ocean-continent transition zones. We present new interpretations of multichannel seismic reflection transects, as well as new petrological data of dredged mantle rocks along the East Antarctic margin (Seamount B, offshore Terre Adélie). By combining both datasets, we show that a 50–100 km wide domain of cold (900°C), fertile subcontinental mantle was exhumed along the non-volcanic Antarctic margin. The dredged peridotites preserve characteristics similar to mantle xenoliths found in syn- to post-rift volcanism at the eastern end of the Australian margin (Victoria and Tasmania), indicating the sampling of a common fertile subcontinental mantle during rifting between Australia and Antarctica. Seamount B represents the initial stages of exhumation of cold subcontinental lithosphere along an ocean-continent transition during rifting. This thick mantle domain was likely affected by syn-rift melt impregnation at high-pressure (8 kbar), leading to the formation of plagioclase-pyroxenites. Overall, the combination of continental rifted blocks, a 50-100 km wide domain of volcanic-poor subcontinental mantle and (ultra)-slow spreading implies that ocean-continent transition zones along the Australian-Antarctic margins represent a recent analogue to ocean continent transition zones from the Jurassic Western Tethys. Additionally, evidence of syn-rift melt stagnation at high pressure suggests that magmatism along the Australian-Antarctic rifted margins was sufficient to form magnetic anomalies that can be used as isochrons despite their formation in lithosphere other than mature, steady-state ocean crust.
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This dataset is a mosaicked product of all publicly available bathymetry data within the Australian Exclusive Economic Zone (EEZ). The data package consists of 8x bathymetry mosaics (and associated bathymetry derivatives: hillshade, slope, aspect) for each of the 8x Parks Australia Management Effectiveness Ecosystem Component depth zones ("Ecosystem Zones"). The grid resolution of the mosaics has been guided by the depth gridding recommendations of the AusSeabed Australian Multibeam Guidelines (2020) to produce the following mosaics: • shallow zone (0-30m): 10m resolution • mesophotic zone (30-70m): 10m resolution • rariphotic zone (70-200m): 10m resolution • upper-slope zone (200-700m): 32m resolution • mid-slope zone (700-2,000m): 64m resolution • lower-slope zone (2,000-4,000m): 128m resolution • abyss zone (4,000-6,000m): 210m resolution • hadal zone (>6,000m): 210m resolution A systematic prioritisation approach was used to preferentially use newer, high-resolution, and cleaner bathymetry inputs from remote sensing (multibeam, singlebeam, satellite, seismic etc), with Digital Elevation Models (DEM) used as foundational data in regions where survey data was not available. This approach optimised spatial resolution by preserving higher resolutions in shallower waters as supported by the data, while also ensuring the output datasets remain manageable for downstream applications. The result is suite of depth-stratified bathymetry mosaics and associated derivatives that provide full coverage of Australia's marine estate (clipped to the boundaries of the Australian Exclusive Economic Zone (EEZ)). All publicly available bathymetry data as at July 2024 for was included. Data can be visualised and used in GIS packages as maps of hillshaded bathymetry and hillshaded slope at the following WMS endpoints: • bathymetry: https://geoserver.imas.utas.edu.au/geoserver/bathy_composites/AusEEZ_bathy_composite_multires/wms?request=GetCapabilities&service=WMS • hillshade: https://geoserver.imas.utas.edu.au/geoserver/bathy_composites/AusEEZ_bathy_hillshade_composite_multires/wms?request=GetCapabilities&service=WMS • slope: https://geoserver.imas.utas.edu.au/geoserver/bathy_composites/AusEEZ_bathy_slope_composite_multires/wms?request=GetCapabilities&service=WMS • aspect: https://geoserver.imas.utas.edu.au/geoserver/bathy_composites/AusEEZ_bathy_aspect_composite_multires/wms?request=GetCapabilities&service=WMS • aspect-slope (for mapping applications only): https://geoserver.imas.utas.edu.au/geoserver/bathy_composites/AusEEZ_bathy_aspectSlope_composite_multires/wms?request=GetCapabilities&service=WMS Data is available for download in the following packages (each structured as 8x mosaics for each Ecosystem Zone at the gridding resolution specified above): (1) bathymetry composites; (2) hillshade composites; (3) slope composites; (4) aspect composites. An ancillary Shapefile footprint index file is also available showing the source data used in generating each region of the mosaics. Note that minimal cleaning of input data was conducted, and no attempt was made to smooth or blend the transitions between swath edges, or between swaths and the underlying DEMs. Consequently, noise and edge effects between adjacent input data may be visible. This should be considered when interpreting the data, and the data should not be used for navigational purposes. See the Lineage section of this record for full methodology.
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The Tasman Fracture CMR AUV survey was a pilot study undertaken in 2014/15 as part of the National Marine Biodiversity Hub's National monitoring, evaluation and reporting theme. The aim of this theme is to develop a bluepint for the sustained monitoring of the South-east Commonwealth Marine Reserve Network. The particular aim of the survey was to contribute to an inventory of the distribution and abundance of demersal fishes in the reserve and adjacent reference sites using BRUVs. Data contained here represents footage collected using these drops and the associated scored data (abundance and lengths).
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This dataset has been superseded by https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/0145df96-3847-474b-8b63-a66f0e03ff54 (Victorian Statewide Marine Habitat Map 2023). The Victorian Benthic Habitats - Port Phillip Bay (CBICS) is a synthesis of all existing benthic habitat characterisations of the embayment which have been reclassified to conform to the Combined Biotope Classification Scheme (CBiCS). Base information for the synthesised dataset were sourced from data provided by: Marine and Freshwater Resources Institute, Queenscliff, Victoria Institute for Sustainability and Innovation, Victoria University, Melbourne. Parks Victoria, Victorian Government Deakin University, Victoria Department of Environment, Land, Water and Planning, Victorian Government
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This dataset has been superseded by https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/0145df96-3847-474b-8b63-a66f0e03ff54 (Victorian Statewide Marine Habitat Map 2023). The Victorian Benthic Habitats - Western Port Bay (CBICS) is a synthesis of all existing benthic habitat characterisations of the embayment which have been reclassified to conform to the Combined Biotope Classification Scheme (CBiCS). Base layers for the synthesised dataset were sourced from data provided by: Marine and Freshwater Resources Institute, Queenscliff, Victoria Institute for Sustainability and Innovation, Victoria University, Melbourne. Parks Victoria, Victorian Government Deakin University, Victoria Department of Environment, Land, Water and Planning, Victorian Government
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This dataset has been superseded by https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/0145df96-3847-474b-8b63-a66f0e03ff54 (Victorian Statewide Marine Habitat Map 2023). The Victorian Benthic Habitats - Gippsland Lakes (CBICS) is a synthesis of all existing benthic habitat characterisations of the Gippsland Lakes Region which have been reclassified to conform to the Combined Biotope Classification Scheme (CBiCS). The study area for this layer is defined as Jack Smith Lake in the west to Mallacoota in the east.
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