This map is part of a series which comprises 50 maps which covers the whole of Australia at a scale of 1:1 000 000 (1cm on a map represents 10km on the ground). Each standard map covers an area of 6 degrees longitude by 4 degrees latitude or about 590 kilometres east to west and about 440 kilometres from north to south. These maps depict natural and constructed features including transport infrastructure (roads, railway airports), hydrography, contours, hypsometric and bathymetric layers, localities and some administrative boundaries, making this a useful general reference map.

Vertical geochemical profiling of the marine Toolebuc Formation, Eromanga Basin - implications for shale gas/oil potential The regionally extensive, marine, mid-Cretaceous (Albian) Toolebuc Formation, Eromanga Basin hosts one of Australia's most prolific potential source rocks. However, its general low thermal maturity precludes pervasive petroleum generation, although regions of high heat flow and/or deeper burial may make it attractive for unconventional (shale gas and shale oil) hydrocarbon exploration. Previous studies have provided a good understanding of the geographic distribution of the marine organic matter in the Toolebuc Formation where total organic carbon (TOC) contents range to over 20% with approx. half being of labile carbon and convertible to gas and oil. This study focuses on the vertical profiling, at the decimetre to metre scale, of the organic and inorganic geochemical fingerprints within the Toolebuc Formation with a view to quantify fluctuations in the depositional environment and mode of preservation of the organic matter and how these factors influence hydrocarbon generation thresholds. The Toolebuc Formation from three wells, Julia Creek-2 and Wallimbulla-2 and -3, was sampled over an interval from 172 to 360m depth. The total core length was 27m from which 60 samples were selected. Cores from the underlying Wallumbilla Formation (11 samples over 13m) and the overlying Allaru Mudstone (3 samples) completed the sample set. Bulk geochemical analyses included %TOC, %carbonate, %total S, -15N kerogen, -13C kerogen, -13C carbonate, -18O carbonate, and major, minor and tracer elements and quantitative mineralogy. More detailed organic geochemical analyses involved molecular fossils (saturated and aromatic hydrocarbons, and metalloporphyrins), compound specific carbon isotopes of n-alkanes, pyrolysis-gas chromatography and compositional kinetics. etc.

TBC

The 'River Murray Corridor (RMC) Salinity Mapping Project', provides important new information in relation to salinity hazard and management along in a 20 km-wide swath along a 450 km reach of the River Murray. The project area contains iconic wetlands, national and state forest parks, irrigation and dryland farming assets and the Murray River, significant areas of which are at risk from increasing salinisation of the River, the floodplain, and underlying groundwater resources. The project utilised a hydrogeological systems approach to integrate and analyse data obtained from a large regional airborne electromagnetic (AEM) survey (24,000 line km @ 150m line-spacing in a 20 km-wide swath along the Murray River), field mapping, and lithological and hydrogeochemical data obtained from drilling. New holistic inversions of the AEM data have been used to map key elements of the hydrogeological system and salinity extent in the shallow sub-surface (top 20-50 m). The Murray River is known to display great complexity in surface-groundwater interactions along its course. Electrical geophysical methods (such as AEM) are able to map surface-groundwater interaction due to the contrast between (electrically resistive) fresh water in the river, and (electrically conductive) brackish to saline groundwater in adjacent sediments. The location of significant river flush zones is influenced both by underlying geology and the location of locks, weirs and irrigation districts. The study has also identified significant areas of high salinity hazard in the floodplain and river, and quantified the salt store and salt load across the floodplain. The study has also identified sub-surface factors (including saline groundwater, shrinking flush zones, declining water tables) linked to vegetation health declines.

To be included in the conference proceedings, expanding on abstract submitted for oral presentation (Geocat No. 73253)

Like many of the basins along Australia's eastern seaboard, there is currently only a limited understanding of the geothermal energy potential of the New South Wales extent of the Clarence-Moreton Basin. To date, no study has examined the existing geological information available to produce an estimate of subsurface temperatures throughout the region. Forward modelling of basin structure using its expected thermal properties is the process generally used in geothermal studies to estimate temperatures at depth in the Earth's crust. The process has seen increasing use in complex three-dimensional (3D) models, including in areas of sparse data. The overall uncertainties of 3D models, including the influence of the broad assumptions required to undertake them, are generally only poorly examined by their authors and sometimes completely ignored. New methods are presented in this study which will allow estimates and uncertainties to be addressed in a quantitative and justifiable way. Specifically, this study applies Monte Carlo Analysis to constrain uncertainties through random sampling of statistically congruent populations. Particular focus has been placed on the uncertainty in assigning thermal conductivity values to complex and spatially extensive geological formations using only limited data. As a case study these new methods are then applied to the New South Wales extent of the Clarence-Moreton Basin. The geological structure of the basin has been modelled using data from existing petroleum drill holes, surface mapping and information derived from previous studies. A range of possible lithological compositions was determined for each of the major geological layers through application of compositional data analysis. In turn, a range of possible thermal conductivity values was determined for the major lithology groups using rock samples held by the NSW Department of Primary Industries (DPI). These two populations of values were then randomly sampled to establish 120 different forward models, the results of which have been interpreted to present the best estimate of expected subsurface temperatures, and their uncertainties. These results suggest that the Clarence-Moreton Basin has a moderate geothermal energy potential within an economic drilling depth. This potential however, displays significant variability between different modelling runs, which is likely due to the limited data available for the region. While further work could improve these methods, it can be seen from this study that uncertainties can provide a means by which to add confidence to results, rather than undermine it.

Geoscience Australia has recently completed a survey searching for evidence of natural hydrocarbon seepage in the offshore northern Perth Basin, off Western Australia. The survey formed part of a regional assessment of the basin's petroleum prospectivity in support of ~17,000 sq km of frontier exploration acreage release in the region in 2011. Multibeam bathymetry, sub-bottom profiler, sidescan sonar and echosounder data were acquired to map seafloor and water column features and characterise the shallow sub-surface sediments. A remotely operated vehicle (ROV) was used to observe and record evidence of seepage on the seafloor. 71 sediment grabs and 28 gravity cores were collected and are currently being analysed for headspace gas, high molecular weight biomarkers and infaunal content. Survey data identified an area of high 'seepage' potential in the northernmost part of the study area. Recent fault reactivation and amplitude anomalies in the shallow strata correlate with raised, high-backscatter regions and pockmarks on the seafloor. A series of hydroacoustic flares identified with the sidescan sonar may represent gas bubbles rising through the water column. The ROV underwater video footage identified a dark-coloured fluid in 500 metres water depth proximal to the sidescan flares which may be oil that naturally seeped from the seafloor. The integration of the datasets acquired during the marine survey is indicative of natural oil seepage and provides additional support for the presence of an active petroleum system on this part of the continental margin.

Cliff Head is the only producing oil field in the offshore Perth Basin. The lack of other exploration success has lead to a perception that the primary source rock onshore (Triassic Kockatea Shale) is absent or has limited generative potential. However, recent offshore well studies show the unit is present and oil prone. Multiple palaeo-oil columns were identified within Permian reservoir below the Kockatea Shale regional seal. This prompted a trap integrity study into fault reactivation as a critical risk for hydrocarbon preservation. Breach of accumulations could be attributed to mid Jurassic extension, Valanginian breakup, margin tilt or Miocene structuring. The study focused on four prospects, covered by 3D seismic data, containing breached and preserved oil columns. 3D geomechanical modelling simulated the response of trap-bounding faults and fluid flow to mid Jurassic-Early Cretaceous NW-SE extension. Calibration of modelling results against fluid inclusion data, as well as current and palaeo-oil columns, demonstrates that along-fault fluid flow correlates with areas of high shear and volumetric strains. Localisation of deformation leads to both an increase in structural permeability promoting fluid flow, and the development of hard-linkages between reactivated Permian reservoir faults and Jurassic faults producing top seal bypass. The main structural factors controlling the distribution of permeable fault segments are: (i) failure for fault strikes 350??110?N; (ii) fault plane intersections generating high shear deformation and dilation; and (iii) preferential reactivation of larger faults shielding neighbouring structures. These results point to a regional predictive approach for assessing trap integrity in the offshore Perth Basin.

The Capricorn Orogen in Western Australia records the punctuated Proterozoic assembly of the Pilbara and Yilgarn Cratons to form the West Australian Craton, and over one billion years of subsequent intracratonic reworking and basin formation. The orogen is over 1000 km long, and includes the passive margin deposits of both the Pilbara and Yilgarn Cratons, variably deformed and metamorphosed granitic and metasedimentary rocks of the Gascoyne Province, and very low- to low-grade metasedimentary rocks that overly these three tectonic units. Several mineral systems have been recognized in the orogen, including the world-class hematite iron-ore deposits of the Hamersley Basin. Other deposits include volcanic-hosted metal sulphide (VHMS) copper-gold deposits, orogenic lode-gold mineralization, various intrusion- and shear zone related base metal, tungsten, rare earth element, uranium and rare-metal deposits, and sediment hosted lead-copper-zinc mineralization. A recent 581 km long vibroseis-source, deep crustal seismic survey across the Capricon Orogen, has provided critical information on the architecture and geological evolution of the orogen. The transect has identified several distinct crustal terranes, each separated by moderately south-dipping suture zones, as well as other major structures that cut through the crust to the mantle. This improved understanding of the Capricorn Orogen has shown that many of the mineral occurrences within the orogen are spatially associated with these crustal-scale structures, which appear to have concentrated fluids, energy, and metals into specific sites in the Capricorn Orogen crust.

Modern geodetic techniques, especially the Global Positioning System (GPS) have allowed the accurate determination of the Earth's surface deformation of Glacial Isostatic Adjustment (GIA) associated with the ongoing stress release of the viscoelastic mantle after removal of the Late Pleistocene ice-sheets. We present an inversion analysis of the GPS derived deformation in North America to determine the effective lithosphere thickness and mantle viscosity, and examine whether the GPS observations can be fit with the ice-sheets and earth models, which were constructed and inferred mainly from geomorphologic/geological and relative sea level (RSL) data. The inversion computation is conducted for horizontal and vertical deformation, separately and jointly with two ice-sheet models (ANU-ICE and ICE-5G) developed independently by the Australian National University (ANU) and University of Toronto. The results from a simple three-layer earth model give a lithosphere thickness of 100~130km, an upper-mantle viscosity of 7~10 × 1020 Pa s, and a lower-mantle viscosity of 1.5~2.8 × 1021 Pa s. More sophisticated models such as introducing a transition zone of 400-670km failed to improve model fit, and the related parameters are mostly consistent with those of three-layer models. Further tests show that models of a thin-layer (30~40km) of large viscosity (~1022 Pa s) did not provide a better fit to the data. Ice scaling tests show that vertical deformation is more sensitive to local ice configuration. An increase of ice thickness by ~40% in Alberta and a reduction by ~50% between Saskatchewan and West Ontario are required to fit both horizontal and vertical deformation observed in Southwest Canada, whereas a reduction of ice thickness by ~25% for ANU-ICE produced an improved fit to both horizontal and vertical deformation in Quebec. Results from inversion analysis of two sub-datasets in Southwest and Southeast Canada revealed a 40% difference in the lower-mantle viscosity, which indicates that the lower-mantle in Southeast Canada could be relatively stronger. There is a discrepancy in the upper-mantle viscosity estimate between horizontal and vertical deformation: a low value (3~5 × 1020 Pa s) required by vertical deformation, and a high value (~9 × 1020 Pa s) favoured by horizontal deformation, which is due possibly to under-represented vertical deformation in the region as well as uncertainties in local ice topography. Overall, the earth model estimated from inversion analysis of GPS data in North America is consistent with the early inference from forward analyses of RSL data (e.g. Tushingham & Peltier, 1992): the lower-mantle viscosity is a factor of 1.5~2.0 larger than upper-mantle viscosity of ~1021 Pa s, reflecting that the main features of the earlier constructed North American ice-sheets (e.g. ICE-3G) are unchanged after two decade refinements.