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.

Inshore benthic habitat mapping of the Adelaide Mount Lofty Ranges (AMLR), Yorke Peninsula, Eyre Peninsula, Upper Spencer Gulf, Upper Gulf St Vincent, South East and Kangaroo Island as part of a wider DEWNR project to map specific areas of the South Australian inshore environments Habitat boundaries were interpreted from underwater features discernable on ortho-rectified aerial photographs. The data for the Upper Gulf St Vincent and Upper Spencer Gulf were captured between 2005 and 2007. AMLR data was captured between 2008 and 2009. South East data was captured between 2009 and 2010. Field observations and underwater video footage was used to capture the Upper Spencer Gulf and Upper Gulf St Vincent data. The AMLR data was captured from field observations, underwater video footage, acoustic mapping and sidescan sonar. The data sets were combined as part of a DENR Statewide project. Additional data was captured on Kangaroo Island during 2013 which included field observations and Underwater video footage. This data was added by regional staff using an adapted data schema that now includes species specific information.

A comprehensive and detailed multibeam sonar-based map of the shelf-break region of the Central Flinders Commonwealth Marine Reserve (CMR). It illustrates the extent that several canyon-head incisions are present in this region, and that inset from the shelf-break is a relatively extensive area of cross-shelf reef. Some of the canyon-head incisions are characterised by exposed reef areas, and these are indicated by localised regions of rapid change in depth. The cross-shelf reef is generally very low profile, but characterised by distinct reef ledges where bedding planes in the sedimentary rock types have eroded. These ledges, often between 1-2 m in height, can run for several kilometres as distinct features. The method of data extraction is based on Lucieer (2013). Three are three classes of seafloor map- one from GEOBIA, one from digitisation and one from Probability of Hardness based on Angular Profile Correction. Lucieer, V (2013) NERP broad-scale analysis of multibeam acoustic data from the Flinders Commonwealth Marine Reserve, Prepared for the National Environmental Research Program. Internal report. IMAS, Hobart, TAS [Contract Report]

This data presents the results of seabed mapping and habitat classification surveys completed in Darwin Harbour during 2011 and 2013 as part of the Northern Territory Government's marine habitat mapping program. This research is a collaboration between Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS), the Department of Land Resource Management (DLRM) and the Darwin Port Corporation. Key objectives are to: - Produce detailed maps of the bathymetry and derived parameters such as slope and rugosity, - Classify the seabed into areas of hard and soft substrate, and, - Produce seabed habitat maps (or seascapes). Key outcomes from the surveys include: 1. Improved understanding of the seabed of Darwin Harbour. The main seabed geomorphic features identified in Darwin Harbour include banks, ridges, plains and scarps, and a deep central channel that divides into smaller and shallower channels. Acoustically hard substrates are found mostly on banks and are associated with rocky reef and sponge gardens, and are often overlain by a thin veneer of sandy sediment. In contrast, plains and channels are characterised by acoustically soft substrates and are associated with fine sediments (mud and sand). 2. Classification of physical seabed properties to produce a Seascape Map for Darwin Harbour. Six seascape classes (potential habitats) were derived using an Iterative Self Organising (ISO) unsupervised classification scheme. These six classes are related to statistically unique combinations of seabed substrate, relief, bedform and presence of sediment veneer (quite often inferred from presence of epibenthic biota).