S-type granites crop out extensively (>2500 km2) in the central and eastern parts of the Hodgkinson Province, north Queensland, Australia, forming two NW to NNW trending belts, outboard of an extensive belt of (mainly late Carboniferous) I-type granites. The S-type granites, which comprise muscovite-biotite syenogranite and monzogranite, and rare granodiorite, have been subdivided in two major supersuites: the Whypalla and Cooktown Supersuites; and a number of minor suites - including the highly differentiated Wangetti and Mount Alto Suites. The S-type granites intrude a very extensive, siliciclastic flysch sequence (late Silurian? to earliest Carboniferous) that is isotopically evolved (e.g., Nd mostly -12.0 to -15.0 at 270 Ma), and generally too mature (too CaO poor) to produce S-type granites. Isotopic and chemical modeling show that although magma-mixing is permissible, the levels permissible (<ca 20-25% basaltic input), are not large enough to explain the signature of the S-type granite. Either more complex mixing models, e.g., crustal melts with a history of mixing, or the presence of more suitable metasedimentary source rocks at depth, is required. The latter is consistent with the (uncommon) presence within the eastern parts of the Hodgkinson Province of metasediments with isotopic signatures similar to the S-type granites. These provide strong support for more extensive such rocks at depth, consistent with other local geology and accretionary tectonic models for the region.

This report is a summary of information collected between November, 1948 and July, 1949 in the course of visits to the United Kingdom and the United States. The main subjects investigated were the complete gasification of coal, particularly in respect of its application to Victorian brown coal, the production of oil by synthesis and the production and refining of shale oil. Information was sought on a considerable number of other interests in the field of fuel technology as the opportunity offered. The authorities consulted were invariably experts in their respective fields, and great care was taken to record their information accurately. The report is a summary of recent developments and not an exhaustive study of the subjects mentioned. A considerable mass of detail has been excluded but is available on record for further reference.

The present report provides a compilation of thermodynamic data for geologically relevant uranium species suitable for geochemical equilibrium calculations from low to moderate temperatures (up to 300°C). It also reports a set of diagrams displaying the solubility of key uranium ore minerals (uraninite, coffinite and carnotite) and the stability of uranium and vanadium complexes at temperatures between 25° and 300°C. Further, it discusses mass-balance calculations of fluid-rock reactions at temperatures up to 200°C relevant to understanding the behaviour of uranium in unconformity-related uranium and sediment-hosted stratiform copper-uranium deposits.

The first large scale projects for geological storage of carbon dioxide on the Australian mainland are likely to occur within sedimentary sequences that underlie or are within the Triassic Cretaceous Great Artesian Basin aquifer sequence. Recent national and state assessments have concluded that certain deep formations within the Great Artesian Basin show considerable geological suitability for the storage of greenhouse gases. These same formations contain trapped methane and naturally generated carbon dioxide stored for millions of years. In July 2010, the Queensland Government released exploration permits for Greenhouse Gas Storage in the Surat and Galilee basins. An important consideration in assessing the potential economic, environmental, health and safety risks of such projects is the potential impact carbon dioxide migrating out of storage reservoirs could have on overlying groundwater resources. The risk and impact of carbon dioxide migrating from a greenhouse gas storage reservoir into groundwater cannot be objectively assessed without an adequate knowledge of the natural baseline characteristics of the groundwater within these systems. Due to the phase behaviour of carbon dioxide, geological storage of carbon dioxide in the supercritical state requires depths greater than 800m, but there are few hydrogeochemical studies of these deeper aquifers in the prospective storage areas. Historical hydrogeochemical data were compiled from various State and Federal Government agencies. In addition, hydrogeochemical information has been compiled from thousands of petroleum well completion reports in order to obtain more information on the deeper aquifers, not typically used for agriculture or human consumption. The data were passed through a quality checking procedure to check for mud contamination and ascertain whether a representative sample had been collected. The large majority of the samples proved to be contaminated but a small selection passed the quality checking criteria.

Globally supracrustal sedimentary rocks are known to preferentially precipitate gold between 2400 Ma and 1800 Ma (Goldfarb et al. 2001). The Palaeoproterozoic Tanami and Pine Creek regions of Northern Australia host one world-class gold deposit and many other gold deposits in anomalously iron-rich marine mudstones (Figure 1). New fluid-rock modelling at temperatures between 275 - 350C suggest a strong correlation between gold grade and these Palaeoproterozoic iron-rich, fine-grained sedimentary rocks.

An abstract outlining capabilities of GA's FreeGs system for geochemical modelling for 1st Russian-Swiss Seminar on "Methods for modelling of geochemical processes: algorithms, data prediction, experimental validation, and relevant applications"

Fluid inclusion studies have been carried out on quartz veining from Jackson's Pit and Eva uranium mines and the Dianne and St Barb copper prospects in the Westmoreland region. Four types of inclusions have been observed. Type A, vapour-rich inclusions, contain 30 - 100 vol.% vapour with varying amounts of CO2 ± N2 ± CH4. Type B, liquid-rich inclusions, contain up to 30 vol.% vapour. Type C inclusions are liquid-only. Type D, three-phase (vapour + liquid + solid) liquid-rich inclusions, contain a small daughter crystal. Type A, vapour-rich inclusions and some Type B, liquid-rich inclusions homogenised over the range 171 to 385°C. Other Type B and Type D inclusions typically homogenised between 100 and 240°C with a mode around 120°C, while the presence of liquid-only inclusions suggests trapping at temperatures below 50°C. This may indicate three phases of fluid flow in the region with progressively cooling fluids. Eutectic melting temperatures as low as -79.8ºC in Type B and C inclusions suggest the presence of CaCl2 and other salts in the fluids. Final ice meeting temperatures for Type B and C inclusions fall into two groups. The first group has final melting temperatures below -10ºC while the second group shows final meeting above -10ºC and more typically close to 0ºC indicating the presence of low salinity fluids. This suggests mixing between saline basinal fluids and low salinity meteoric fluids that continued down to temperatures below 50°C.

Geophysical responses, such as gravity anomalies, arise from variations in physical properties, such as density, in the subsurface. These physical properties are predominantly controlled by mineralogy. Chemical alteration varies the mineralogy of a rock, potentially producing a geophysical response due to the alteration. Physical property models can be calculated for numerical simulations of chemical alteration, such as reactive transport simulations; these physical properties allow the geophysical signatures of alteration to be calculated.

High-CO2 gas fields serve as important analogues for understanding various processes related to CO2 injection and storage. The chemical signatures, both within the fluids and the solid phases, are especially useful for elucidating preferred gas migration pathways and also for assessing the relative importance of mineral dissolution and/or solution trapping efficiency. In this paper, we present a high resolution study focused on the Gorgon gas field and associated Rankin trend gases on Australia's Northwest Shelf of Australia. The gas data we present here display correlate-able trends for mole %-CO2 and %C CO2 both areally and vertically. Generally, CO2 % decreases and becomes depleted in %C (lighter) upsection and towards the north; a trend which also holds true for the greater Rankin trend gases in general. The strong spatial variation of CO2 content and %C and the interrelationship between the two suggests that processes were active to alter the two in tandem. We propose that these variations were driven by the precipitation of a carbonate phase, namely siderite, which is observed as a common late stage mineral. This conclusion is based on Rayleigh distillation modeling together with bulk rock isotopic analyses of core, which confirms that CO2 in gases are genetically related to the late stage carbonate cements. The results from this study have important implications for carbon storage operations and suggest that significant CO2 may be reacted out a gas plume over short migration distances.

Several scenarios of an original 3D model based on the petroleum systems model of Fuji et al. (APPEA 2004) were simulated using the PetroMod 3D V.10 modeling software. In general the results of the modelling study presented here confirms the modelling results of Fuji et al. (2004) with respect to the timing of generation in the different sub-basins as well as present day maturity. The main differences between the work of Fuji et al. (2004) and the work presented here are based on the use of PhaseKinetic models for the individual source rock formations and the ensuing compositional predictions of the fluids in different fields. Source rock transformation ratios as well as the bulk generation rates indicate that the source rocks are presently still generating. The Central Swan Graben area is presently more mature than the other kitchen area of the Vulcan Sub-basin, the Cartier Trough. The locations of predicted accumulations coincide with the locations of most of the proven fields. In many cases accumulation sizes and predicted column heights are large, mainly due to the fact that the resolution of the numerical model is low which leaves rather large volumes of the cells to be filled. Modelling results predict a series of accumulations at locations which have, as yet, not been tested. However, most of them depend on fault closure, thus increasing exploration risk. The main risks as observed from this modelling exercise are: 1) source rock presence and definition, 2) definition of the traps, 3) resolution of the input model, 4) cap rock properties, which are still largely unconstrained. The different scenarios modelled show distinct variations with respect to predicted petroleum distribution as well as the physical properties of the accumulated fluids.