This record contains the substantive results of Geoscience Australia marine survey SS08/2005 to the SW margin of Australia. The survey was completed between 28 September and 20 October 2005 using Australia’s national facility research vessel Southern Surveyor. The survey included scientists from Geoscience Australia, CSIRO – Marine and Atmospheric Research, and Victoria Museum. The survey was co‐funded by Geoscience Australia and the Department of the Environment and Heritage (now the Department of the Environment, Water, Heritage and the Arts). The principal aims of the survey were to explore deep‐sea habitats and processes in submarine canyons on the SW margin, and examine the geology of the underlying Mentelle Basin as an assessment for its petroleum potential.

The deposits of heavy-mineral sands which are at present being exploited along the East Coast occur on or within a few hundred feet of the ocean beaches. The occurrence of this deposit at a distance of nearly 1.5 miles from the beach suggests the possibility that other deposits may be found at some distance from the coast line. Of incidental interest is the possibility that the deposit, which presumably was formed by wave or surf action, may be at slightly higher level than the deposits adjacent to present day beaches. The locality, examination process, origin, and nature of the deposits are discussed in this report. The results, including estimates of the quantities of heavy mineral concentrates and the grades of the mineral bearing sands, are tabulated here.

These preliminary notes deal with the sequence as it is found in the Giralia Structure. The analysis of the Cretaceous-Tertiary megafauna is described. The findings of the investigation with respect to the sedimentary sequence are discussed.

The writer spent four days in 1949 in the Adaminaby-Kiandra Area with J. Glover mapping the country north-north-east of the present Tunnel Line. In 1951 a fortnight more was spent on the Tunnel Lines themselves by the writer under the guidance of senior geologist D.C. Moye and geologists K. Sharp and C. Wood, who provided a large amount of information not yet available in written form. All sediments in the Tunnel Area are Ordovician, and in the case of the Tumut Pond beds an even older age is possible.

A high resolution sequence stratigraphic study has been undertaken on the three wells in the Houtman Sub-basin, offshore North Perth Basin: Gun Island 1 (1968), Houtman 1 (1978) and Charon 1 (2008). The study focussed on the late Jurassic Yarragadee Formation, mid Jurassic Cadda Formation and early Jurassic Cattamarra Coal Measures. Log character (particularly gamma ray and sonic), cuttings, sidewall core and conventional core lithologies (including sedimentary structures) and palynological data were used to identify paleoenvironments. Stacking patterns of the interpreted environments were used to define systems tracts and then sequences. New palynological data have been collected by Geoscience Australia for Gun Island 1 and the palynology for all wells has been reviewed from Well Completion Reports and slides from intervals in each well. A number of transgressive systems tracts within the dominantly continental Yarragadee Formation and Cattamarra Coal Measures record small marine incursions into the Houtman Sub-basin. Within these units, the shallow marine intervals switch rapidly with non-marine intervals suggesting a more dynamic environment existed in the Houtman Sub-basin during the Jurassic than previously thought. These marine incursions are not evident in the Yarragadee Formation in Charon 1, indicating a lack of accommodation space or proximal sediment input into the north during the mid-late Jurassic. This has significant implications for reservoir and seal facies of potential Mesozoic petroleum systems in the Houtman Sub-basin.

This resource contains surface sediment data for Bynoe Harbour collected by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and Department of Land Resource Management (Northern Territory Government) during the period from 2-29 May 2016 on the RV Solander (survey SOL6432/GA4452). This project was made possible through offset funds provided by INPEX-led Ichthys LNG Project to Northern Territory Government Department of Land Resource Management, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The intent of this four year (2014-2018) program is to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline data that enable the creation of thematic habitat maps that underpin marine resource management decisions. The specific objectives of the survey were to: 1. Obtain high resolution geophysical (bathymetry) data for outer Darwin Harbour, including Shoal Bay; 2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for outer Darwin Harbour, including Shoal Bay; and 3. Collect tidal data for the survey area. Data acquired during the survey included: multibeam sonar bathymetry and acoustic backscatter; physical samples of seabed sediments, underwater photography and video of grab sample locations and oceanographic information including tidal data and sound velocity profiles. This dataset comprises grain size data measured on seabed sediments. A detailed account of the survey is provided in Siwabessy, P.J.W., Smit, N., Atkinson, I., Dando, N., Harries, S., Howard, F.J.F., Li, J., Nicholas W.A., Picard, K., Radke, L.C., Tran, M., Williams, D. and Whiteway, T., 2016. Bynoe Harbour Marine Survey 2017: GA4452/SOL6432 - Post-survey report. Record 2017/04. Geoscience Australia, Canberra. Thanks to the crew of the RV Solander for help with sample collection, Matt Carey, Craig Wintle and Andrew Hislop from the Observatories and Science Support at Geoscience Australia for technical support and Jodie Smith for reviewing the data. This dataset is published with the permission of the CEO, Geoscience Australia

Increased loads of land-based pollutants associated with land use change are a major threat to coastal-marine ecosystems globally. Identifying the affected areas and the scale of influence on marine ecosystems is critical to assess the ecological impacts of degraded water quality and to inform planning for catchment management and marine conservation. Studies using remotely-sensed data have contributed to our understanding of the occurrence and extent of influence of river plumes, as well as to assess exposure of ecosystems to river-borne pollutants. However, refinement of plume modelling techniques is required to improve risk assessments. We developed a novel approach to model exposure of coastal-marine ecosystems to river-borne pollutants. The model is based on supervised classification of true-colour satellite imagery to map the extent of plumes and to qualitatively assess the dispersal of pollutants in plumes. We use the Great Barrier Reef (GBR) to test our approach. We combined frequency of plume occurrence with spatially-distributed loads (based on a cost-distance function) to create maps of exposure to suspended sediment and dissolved inorganic nitrogen. We then compared annual exposure maps (2007-2011) to assess inter-annual variability in the exposure of coral reefs and seagrass beds. Our findings indicate that classification of true colour satellite images is useful to map plumes and to qualitatively assess exposure to river-borne pollutants. This approach should be considered complementary to remote sensing methods based on ocean colour products used to characterise surface water in plumes. The proposed exposure model is useful to study the spatial and temporal variation in exposure of coastal-marine ecosystems to riverine plumes. Observed inter-annual variation in exposure of habitats to pollutants stresses the need to incorporate the temporal component in exposure and risk models.

The sediments deposited beneath the floating ice shelves around the Antarctic margin provide important clues regarding the nature of sub-ice shelf circulation and the imprint of ice sheet dynamics and marine incursions on the sedimentary record. Understanding the nature of sedimentary deposits beneath ice shelves is important for reconstructing the icesheet history from shelf sediments. In addition, down core records from beneath ice shelves can be used to understand the past dynamics of the ice sheet. Six sediment cores have been collected from beneath the Amery Ice Shelf in East Antarctica, at distances from the ice edge of between 100 and 300 km. The sediment cores collected beneath this ice shelf provide a record of deglaciation on the Prydz Bay shelf following the last glaciation. Diatoms and other microfossils preserved in the cores reveal the occurrence and strength of marine incursions beneath the ice shelf, and indicate the varying marine influence between regions of the sub-ice shelf environment. Variations in diatom species also reveal changes in sea ice conditions in Prydz Bay during the deglaciation. Grain size analysis indicates the varying proximity to the grounding line through the deglaciation, and the timing of ice sheet retreat across the shelf based on 14C dating of the cores. Two of the cores contain evidence of cross-bedding towards the base of the core. These cross-beds most likely reflect tidal pumping at the base of the ice shelf at a time when these sites were close to the grounding line of the Lambert Glacier.

No abstract available

Seasonal variations in major ions, nutrients and chlorophyll a were examined at two sites in the upper reaches of the Swan River estuary, Western Australia. Intra-annual variations between the variables were strongly influenced by seasonal riverine discharge, though major ions behaved highly conservatively across a wide range of salinity. Reduced discharge following winter produced strong density stratification that coincided with upstream salt wedge propagation and produced distinct physico-chemical identities of surface and bottom waters. Anoxia of bottom waters associated with the salt wedge region induced increased concentrations of ammonium and phosphate, especially at the deeper of the two sites. Locally variable groundwater flow may have also been important in transporting sediment porewater nutrients into the water column. The seasonality of riverine discharge produced large intra-annual variations in temperature (13-29°C) and salinity (3-30). Transient increases in turbidity occurred when the salt wedge coincided with the position of sampling locations. The subsequent flocculation process likely contributed to further oxygen consumption and nutrient regeneration from the bottom sediments, while simultaneously depositing nutrient-rich flocs with low molar N:P ratios (3-8) to the sediment surface. Nutrient ratios and absolute nutrient concentrations suggest that nitrogen is the nutrient most likely to limit phytoplankton growth over most of the year.