The Surface Hydrology Points (Regional) dataset provides a set of related features classes to be used as the basis of the production of consistent hydrological information. This dataset contains a geometric representation of major hydrographic point elements - both natural and artificial. This dataset is the best available data supplied by Jurisdictions and aggregated by Geoscience Australia it is intended for defining hydrological features.

This dataset is the most current national compilation of catchment scale land use data for Australia (CLUM), as at March 2015. It is a seamless raster dataset that combines land use data for all state and territory jurisdictions, compiled at a resolution of 50 metres by 50 metres. It has been compiled from vector land use datasets collected as part of state and territory mapping programs through the Australian Collaborative Land Use and Management Program (ACLUMP). Catchment scale land use data was produced by combining land tenure and other types of land use information, fine-scale satellite data and information collected in the field. The date of mapping (1997 to 2014) and scale of mapping (1:20 000 to 1:250 000) vary, reflecting the source data capture date and scale. This information is provided in a supporting polygon dataset.

Extensive historical (anecdotal) information covering the past 3 decades indicated that the remote and pristine Nadgee lake estuary in southern NSW had a benthic dominated ecology. All descriptions indicated that it had oligotrophic waters with dense cover of benthic macropyhtes and associated avifauna. When we arrived at Nadgee in late 2008 for the first scientific aquatic survey (ever) it looked nothing like this. The lake was dominated by an intense microalgal bloom and no macrophytes were present. Why? Entrance opening and closure are the major disturbances in an intermittent estuary like Nadgee, but there are no records of past entrance behaviour for such a remote site. This paper describes the use of Geoscience Australia's recent compilation and rectification of Landsat images (the Australian Geoscience Data Cube), along with the application of a consistent water detection tool for all pixels in that compilation, to determine opening and closing regimes. The output of the analyses provides an indication of whether a pixel was wet or dry (or not able to be determined) for all images over the entire 27 year's worth of data. Water level records measured by OEH since 2009 were used to ground-truth the remote sensed data. We can now determine when, over the past 27 years, the Lake opened and how long the water level remained low. This information, along with an understanding of the ecology of the primary macrophytes has been used to provide some possible models that explain when and why the fundamental shift from benthic to pelagic may have occurred.

The National Flood Risk Informaiton Project (NFRIp) has produced a flyer for the Floodplain Management Association Conference on 19-22 May 2015 where the Australian Flood Risk Information Portal (AFRIP) will be promoted at a Geoscience Australia booth. NFRIP funded the revision of the guidelines as part of a $12m funding initiative by the Australia Government. The flyer promotes the three core activities of NFRIP; the Australian Flood Risk Information Portal, revision of Australian Rainfall and Runoff guidelines and Water Observations from Space (WOfS).

How we use crystallography Although the discipline of Geology is more than just rocks, the study of rocks and minerals make up a large part of our work. We analyse rocks and minerals from across Australia from samples collected under the sea, at the surface or from deep drill holes. Recently for example, our Minerals programme has drilled 14 holes through young cover to gather samples of basement rocks believed to be prospective for copper mineralisation in western Victoria.

In probabilistic seismic hazard modelling the choice of whether faults behave with Characteristic or Gutenberg-Richter recurrence statistics has a high impact on the hazard level. Compared to a model that does not include fault sources, the addition of a high slip rate (by intraplate standards) Characteristic fault results in a modest increase in hazard for a 500 years return period event, and a modest increase at longer return periods (i.e. ~2500 years). A Gutenberg-Richter fault with the same slip rate will result in a comparatively higher hazard at 500 years, similar hazard at 2500 years and a lower hazard a very long return periods (i.e. ~5000 years). Results from interplate and active intraplate paleoseismological investigations since the mid-1980s have been used to suggest that earthquakes recurrent on a given fault often have the same characteristic rupture length and amount of slip (i.e. a Characteristic Rupture Model). Stable asperities and barriers, which survive many earthquakes, are proposed to explain these results. The scarcity of data precludes definitive validation of the model in Australian Stable Continental Region crust. However, preliminary indications are that the Characteristic Rupture Model has some merit in cratonic regions of the country while faults in non-cratonic regions may behave in a more complex fashion.

Geoscience Australia conducted a marine survey in the Caswell Sub-basin of the Browse Basin, offshore Western Australia, in late 2014 to investigate containment questions relating to the potential long-term geological storage of CO2. The survey aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may suggest the presence of deep plumbing systems which could compromise seal integrity. Prior to the survey, 2D and 3D seismic data were used to map fault networks connecting the Aptian regional seal to the sea floor and any associated amplitude anomalies. This mapping informed survey site selection aimed at testing seal integrity over Maastrichtian, Campanian, Valanginian and Barremian submarine fans in the Caswell Sub-basin, and up-dip migration and leakage of hydrocarbons, via channels and basin margin faults, such as the Heywood Fault, into shallow marine sands on the eastern shelf margin. Vessel and Autonomous Underwater Vehicle (AUV) multibeam bathymetry and sub-bottom profiler systems confirmed the presence of recently active faults in the area, some with significant seafloor surface expression (up to 40m offset). A subset of these faults was visually inspected with a Remotely Operated Vehicle (ROV) which also confirmed the presence of diverse biological communities. Indications of shallow gas were observed on sub-bottom profiles, including amplitude anomalies, cross-cutting reflectors and zones of signal starvation. Water column observations including sidescan sonar, single-beam and multibeam echosounders, underwater video and photography did not conclusively identify hydrocarbon or other fluid seepage. Strong currents encountered during parts of the survey may have interfered with the direct detection of seeps in the water column. However, headspace gas and high-molecular weight hydrocarbon analysis from shallow cores also provided no evidence for migrated thermogenic gas or oil. While no active signs of seepage were observed, the geochemical and biological sampling undertaken will aid in baseline environmental investigations for this region.

We propose a surface cover change detection system based on the Australian Geoscience Data Cube (AGDC). The AGDC is a common analytical framework for large volumes of regularly gridded geoscientific data initially developed by Geoscience Australia (GA). AGDC effectively links geoscience data sets from various sources by spatial and temporal stamps associated with the data. Therefore, AGDC enables analysis of generations of consistent remote sensing time series data across Australia. The Australian Reflectance Grid 25m is one of the remote sensing data sets in the AGDC. The data is currently hosted at the high performance computational cloud at the National Computational Infrastructure. The proposed change detection system takes advantage of temporally rich data in the AGDC, applying time series analysis to identify changes in surface cover. The proposed system consists of various modules, which are independent of each other. The modules include: - a pixel quality mask and time series noise detection mask, which detects and filters out noise in data; - spectral classification modules based on random forests algorithm, which classifies pixels into specific objects using spectral information; - training modules which create classification modules using known surface cover data; - time series analysis modules, which models and transforms time series data into coefficients relevant to change detection targets; - temporal and spatial classification modules, which classify pixels into predefined land cover classes. A typical work flow for a change detection system includes sequential integration of the above mentioned modules. The system has been tested for applications in shallow water coastal zones and reforestation / deforestation detection, and displays a good potential for further development. This paper summarises development of the work flow and the initial results from example applications, such as reforestation / deforestation detection.

Tholeiitic intrusion-hosted nickel sulphide deposits are highly sort exploration targets due to their potential size and co-products platinum-group elements and copper. The Norilsk-Talnakh (Russia), Voisey's Bay (Canada) and Jinchuan (China) deposits are world class examples. Although Australia holds the largest economic resources of nickel in the world, its nickel resources are mainly sourced from komatiitic-hosted and lateritic deposits. Known resources of tholeiitic intrusion-hosted nickel sulphides are relatively small, with Nebo-Babel and Nova-Bollinger in Western Australia the most significant examples. Given the abundance of tholeiitic igneous rocks in Australia, this important deposit type seems to be under-represented when compared to other continents with similar geology. To support the discovery of world class nickel sulphide deposits in Australia, Geoscience Australia has recently undertaken a continental-scale GIS-based prospectivity analysis for tholeiitic intrusion-hosted deposits across Australia. This analysis exploits a suite of new relevant digital datasets recently released by Geoscience Australia. For example, the analysis utilises the Australian Mafic-Ultramafic Magmatic Events GIS Dataset which places mafic and ultramafic rocks across Australia into 74 coeval magmatic events based on geochronological data. Whole rock geochemistry of mafic and ultramafic rocks has been used to differentiate between magma series and discriminate between different magmatic events and units within those events. Other new datasets include crustal domain boundaries derived from both deep crustal seismic data and neodymium depleted mantle model age data as well as a coverage of the minimum thickness of mafic rocks in the crust derived from the Australian Seismogenic Reference Earth Model. This continental-scale GIS-based nickel sulphide prospectivity analysis uses a mineral systems approach to map the four essential components of ore-forming mineral systems; (1) sources of ore constituents, (2) crustal and mantle lithospheric architecture, (3) energy sources or drivers of the ore-forming system, and (4) gradients in ore depositional physico-chemical parameters. These four components are combined into a prospectivity map using weights-of-evidence GIS-based techniques, with the most prospective areas across the continent occurring where all components are present. The mineral systems approach allows for the identification of a much larger footprint than the deposit itself, and can be applied to greenfield and/or undercover areas. The results highlight areas that contain known tholeiitic intrusion-hosted nickel sulphide deposits, such as the Musgrave and Pilbara Provinces, as well as regions that do not contain any known deposits, such as the southern margin of the Arunta Province in the Northern Territory, the Mount Isa Province in Queensland and the Paterson Province in Western Australia.

The Early Cretaceous Gage Sandstone and South Perth Shale are a prospective reservoir-seal pair in the Warnbro Group of offshore Vlaming Sub-basin, Western Australia. Gage Sandstone reservoir plays include post-breakup pinch-outs against the Valanginian Unconformity, and 4-way dip closures with the South Perth Shale forming the top seal. Deposited as a lowstand component of the deltaic South Perth Supersequence, the Gage Lowstand Fan (previously referred to as the Gage Sandstone) infilled palaeotopographic lows of the Valanginian breakup unconformity. Sequence stratigraphic analysis was used to characterise the reservoir-seal pair by integrating 2D seismic interpretation, well log analysis and new biostratigraphic data. Palaeogeographic mapping of the South Perth Supersequence reveal a series of regressions and transgressions that lead to the infilling of the central palaeodepression. The Gage reservoir is a sand-rich submarine fan system and ranges from canyon-confined inner fan deposits to middle fan deposits on a basin plain. Major sediment contributions were from north-south trending canyons adjacent to the Mandurah Terrace. More detailed seismic facies mapping and well log analysis of the Gage Lowstand Fan determined that the sand sheets in the distal middle fan and stacked channelized sands in the inner fan may provide an extensive reservoir of good to excellent quality. Seal quality varies greatly and may explain the lack of exploration success at some structural closures. A re-evaluation of the regional seal determined the extent of the pro-delta shale facies within the South Perth Supersequence that provides an effective seal for the underlying Gage reservoir. 3D geological modelling confirms that the Gage reservoir exhibits properties suitable for hydrocarbon entrapment and CO2 storage. Migration path analysis identified the presence of multiple structural and stratigraphic closures at the top of the Gage reservoir, with the most favourable located in the Rottnest Trough. Previous petroleum systems modelling concluded that the maturity of some source rocks in the sub-basin likely occurred after the deposition of the effective seal. Deep-seated faults, penetrating the syn-rift section, are in direct contact with the Gage reservoir and it could be actively receiving hydrocarbon charge.