Abstract: The extent to which fluids may leak from sedimentary basins to the seabed is a critical issue for assessing the potential of a basin for carbon capture and storage. The Petrel Sub-basin, located beneath central and eastern Joseph Bonaparte Gulf in tropical northern Australia, is identified as potentially suitable for the geological storage of CO2 because of its geological characteristics and proximity to offshore gas and petroleum resources. In May 2012, a multidisciplinary marine survey was undertaken to collect data in two targeted areas of the Petrel Sub-basin to facilitate an assessment of CO2 storage potential. Multibeam bathymetry and backscatter mapping (650 km2 over 5,300 line km), combined with acoustic sub-bottom profiling (650 line km) and geomorphological and sediment characterisation of the seabed was undertaken above the CO2 supercritical seal boundary of the sub-basin. Features identified in the high resolution (2 m) bathymetry data include carbonate banks, ridges, pockmark fields and fields of low amplitude hummocks located directly adjacent to banks. Unit and composite pockmarks and clusters of pockmarks are present on plains and adjacent to, and on, carbonate ridges. It is postulated that there are three possible sources for fluids and fluidised gas involved in pockmark formation: deep fluids from the basin, post-Cretaceous intra-formational, layer-bound fluids, and shallow-sourced fluidised gas from the breakdown of organic matter following the Holocene marine transgression of Joseph Bonaparte Gulf.

This unique, interactive map shows how crowdsourced photographs can help to highlight some of Australia's great geological features. The interactive map, built using the ESRI Storymap functionality, combines geolocation information with superb imagery gathered by amateur and professional photographers. The map features the best 68 images selected from over 300 entries in the 2015 Top GeoShot photographic competition.

Here we present the surficial geology map for the Vestfold Hills, East Antarctica. On the coast of Prydz Bay, the region is one of the largest ice-free areas in Antarctica. Surficial geology mapping at 1:2000 was undertaken with field observations in the 2018/19 and 2019/20 summer seasons as well as aerial photography and satellite imagery interpretation. Units are based on the Geological Survey of Canada Surficial Data Model Version 2.4.0 (Deblonde et al 2019).

This flythrough highlights canyon environments within the Gascoyne Marine Park offshore northwestern Australia. The Cape Range Canyon is a relatively narrow, linear canyon that initiates on the continental slope, but is connected to the shelf via a narrow channel. The walls of the canyon are steep and reveal a history of slumping and retrogressive failure, that have broadened the canyon over time. The floor contains a series of deep plunge pools, indicative of the action of sediment-laden turbidity currents in further eroding this canyon. Epibenthos within the canyons was relatively sparse and likely regulated by disturbance associated with sedimentation in the canyons. Rock overhangs often supported the highest densities of benthic suspension feeders, including glass sponges, octocorals, and ascidians. Bathymetry data and seafloor imagery for this flythrough was collected by the Schmidt Ocean Institute during survey FK200308. Funding was provided by Schmidt Ocean Institute, Geoscience Australia, the Australian Government’s National Environmental Science Program (NESP) Marine Biodiversity Hub, the Director of National Parks, and the Foundation for the WA Museum through a Woodside Marine Biodiversity Grant.

Managed aquifer recharge (MAR) enhances recharge to aquifers. As part of the Exploring for the Future Southern Stuart Corridor project, remotely sensed data were used to map regolith materials and landforms, and to identify areas that represent potential MAR target areas for future investigation. Nine areas were identified, predominantly associated with alluvial landforms in low-gradient landscape settings. The surface materials are typically sandy, or sandy and silty, with the prospective areas overlying newly identified groundwater resources associated with Paleozoic sedimentary rocks of the Wiso and Georgina basins. The workflow used here can be rapidly rolled out across broader areas, and can be supplemented by higher-resolution, longer time-series remote-sensing data, coupled with data analytics, modelling and expert knowledge. Such an approach will help to identify areas of the arid interior that may be suitable for MAR schemes that could supplement water for remote communities, and agricultural and other natural resource developments. <b>Citation:</b> Smith, M.L., Hostetler, S. and Northey, J., 2020. Managed aquifer recharge prospectivity mapping in the Northern Territory arid zone using remotely sensed data. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

The deep waters within the Gascoyne Marine Park have been largely unexplored for their seafloor biodiversity. Survey FK200308 on the RV Falkor targeted two canyons within the Gascoyne Marine Park to understand and map the distribution and diversity of marine habitats and biota within the Cape Range and Cloates Canyons. These canyons were targeted to better understand their ecological significance as a conduit between shelf environments adjacent to the Ningaloo Reef and the abyssal plain. They occur within the habitat protection and multiple use zones of the Gascoyne Marine Park off north-western Australia. Survey FK200308 was led by researchers at the Western Australian Museum, and included scientists from Geoscience Australia, Curtin University, Macquarie University and Scripps Institute of Oceanography. Multibeam sonar was used to map parts of the marine park, while a Remotely Operated Vehicle (ROV) was deployed to undertake a comprehensive taxon inventory of the North-West canyon fauna based on underwater imagery and sampling. Additional biological samples were collected via plankton sampling, as well as fish and crustacean traps on a lander, and stand-alone fish trap deployments. Autonomous Reef Monitoring Structures (ARMS) were deployed at select sites to capture cryptic benthic organisms over several years. DNA samples from the water column (eDNA) were collected to enable a broader understanding of the biodiversity of the region, and to provide a methodological comparison to the organisms present at the time of sampling. The key drivers for this survey were to collect Information to enhance our understanding of the Gascoyne Marine Park and deep-sea environments throughout Western Australia, and to facilitate comparisons between the north-west and eastern and southern Australian deep-sea waters. This information can be applied to inform management plans, scientific research and industry activities for the North-West. Specifically, this survey provided: • A faunal inventory as a baseline information for monitoring deep water WA environments. A total of 2570 seafloor images were annotated from quantitative transects, more than 1000 specimens were collected and up to 30 new species discovered. • High resolution mapping of the seafloor across an area of 11,250 km2 revealed a detailed understanding of seabed habitats and environments in the Gascoyne Marine Park, and a regional context in which to interpret the faunal inventory. • Repeat multibeam mapping of the Cape Range and Cloates Canyons informed our understanding of seabed stability in the canyons of the Gascoyne Marine park, illustrating a rare case of true monitoring using multibeam in Australian waters. • The use of a state-of-the-art ROV across 20 deployments helped inform a new ROV field manual (Monk et al. 2020), adding to the existing suite of standard operating procedures supported by Parks Australia (https://marine-sampling-field-manual.github.io/). This survey confirmed that canyons within the Gascoyne Marine Park are important ecological systems, supporting numerous deep-sea species, many of which were discovered to be new to science. The advanced capabilities of the ROV SuBastian to navigate and image complex near vertical walls and overhangs within the canyons revealed patterns in the distribution of the seafloor taxa consistent with small-scale environmental variability. Repeat multibeam mapping revealed a dynamic canyon system that continues to be shaped by turbidity events. The occurrence of reworked seagrass blades within the canyons provided new understanding of these canyon systems as an active conduit between shallow shelf and abyssal environments. The distribution of the seabed biota revealed through quantitative ROV transects emphasised the importance of disturbance patterns in shaping the canyon ecosystems.

This flythrough video highlights deep and mesophotic seabed environments within the Coral Sea Marine Park, offshore northeastern Australia. The mesophotic zone, commonly referred to as the ‘twilight zone’ represents the depth range below the brightly lit shallow waters down to the maximum depth that sunlight can penetrate for photosynthesis to occur (~ 30 to 150 meters beneath the sea surface). The featured Malay and North Flinders Reefs represent mid-ocean platform reefs and Cairns Seamount hosts a thriving coral reef community atop what is likely an extinct volcanic cone. These locations represent a range of benthic communities, which vary with depth and substrate type. Soft-sediments (sands, muds and oozes) dominate the deep seafloor, with evidence of water currents that produce bedforms showing active sediment transport at these depths. The walls and flanks of the platform reefs are very steep, with evidence of slope failure where rocky head walls have collapsed and deposited large blocks and boulders on the seafloor, which provide important habitat for sessile and mobile invertebrates including soft corals and sponges as well as cryptic octopus. Typical mesophotic habitats included vast Halimeda algal meadows and rhodolith beds interspersed with soft corals and sponges on soft-sediment. Hard substrates were typically colonised by plate and encrusting hard Scleractinian corals (e.g. Leptoseris and Montipora species), sponges and ascidians. Many large black corals (Antipatharia) and gorgonians (Octocorallia) also featured, with several black coral and carnivorous sponge observations representing new species. The reef community atop Cairns Seamount was highly diverse and included many demersal and pelagic fish species. A high abundance and diversity of gelatinous zooplankton were observed in the deep waters between reefs in the Coral Sea, with several new range extensions recorded. Bathymetry data and seafloor imagery for this flythrough were collected on RV Falkor, owned and operated by the Schmidt Ocean Institute (SOI), during surveys FK200830 and FK200902 in August and October 2020. These surveys were led by Geoscience Australia and James Cook University. Collaborative research partners included the Japan Agency for Marine-Earth Science and Technology, The University of Tokyo, Queensland University of Technology, Queensland Museum, The University of Sydney, University of Tasmania and the University of Wollongong.

Remotely sensed data and updated DEM and radiometric datasets, combined with existing surface material and landform mapping were used to map regolith landform units for the Ti Tree, Western Davenport and Tennant Creek regions of the SSC project. This report describes the methods used and outlines the new mapping.

Remotely sensed data and updated DEM and radiometric datasets, combined with existing surface material and landform mapping were used to map regolith landform units for the Alice Springs study area of the SSC project. This report describes the methods used and outlines the new mapping.

The East Antarctic slope on the Sabrina margin has been shaped by diverse processes related to repeated glaciation. Differences in slope along this margin have driven variations in sedimentation that explain the gully morphology. Areas of lower slope angles have led to rapid sediment deposition during glacial expansion to the shelf edge, and subsequent sediment failure. Gullies in these areas are typically extremely U-shaped, initiate well below the shelf break, are relatively straight and long, and have low incision depths. Areas of higher slope angles enhance the flow of erosive turbidity currents during glaciations associated with the release of sediment-laden basal meltwaters. The meltwater flows create gullies that typically initiate at or near the shelf break, are V-shaped in profiles, have high sinuosity, deep incision depths and a relatively short down slope extent. The short down slope extent reflects a reduced sediment load associated with increased seawater entrainment as the slope becomes more concave in profile. These differences in gully morphology have important habitat implications, associated with differences in the structure and beta-diversity of the seafloor communities. This upper slope region also supports seafloor communities that are distinct from those on the adjacent shelf, highlighting the uniqueness of this environment for biodiversity. <b>Citation:</b> A.L. Post, P.E. O'Brien, S. Edwards, A.G. Carroll, K. Malakoff, L.K. Armand, Upper slope processes and seafloor ecosystems on the Sabrina continental slope, East Antarctica, <i>Marine Geology</i>, Volume 422, 2020, 106091, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2019.106091.