This data package was preduced in response to a request by Rodney King from Teck Australia for a compilation of GA borehole datasets from the Isa Superbasin, in particular for gamma-ray data. The data set includes drill hole/section location information, and lithological, geochemical and gamma ray data. All data were extracted from GA databases.

Australian Proterozoic orogenic belts are typically characterised by high-temperature, low-pressure, long-lived metamorphism and near-isobaric cooling. However, this is not the case for the Nimbuwah Domain, the easternmost part of the Pine Creek Orogen and part of the oldest core of the North Australian Craton. Here we present new field relationships, geochemical, metamorphic, SHRIMP zircon and monazite U-Pb age, and zircon Lu-Hf and whole-rock Sm-Nd isotopic data for the Nimbuwah Complex and metasedimentary rocks of the Cahill Formation that they intruded in the Nimbuwah Domain. On the basis of these data we propose a new tectonic model for the Paleoproterozoic evolution of the Pine Creek Orogen. SHRIMP zircon U-Pb age data show that granitic to dioritic plutons of the Nimbuwah Complex were emplaced from 1871-1857 Ma at - 9.2 kbar and 650-C into thickened crust during D2-D3 west-directed thrusting and folding. This is termed the Nimbuwah Event. The Nimbuwah Complex was formed by partial melting of Neoarchean granites in the mid to lower crust and mixing with a juvenile magma component. The overthickened crust underwent extensional uplift to <5 kbar by 1855 Ma, constrained by monazite growth during garnet breakdown associated with syn- to late-D2 decompression. We propose that crustal thickening and magmatism occurred in response to collision of Neoarchean to Paleoproterozoic basement of the Pine Creek Orogen (the over-riding plate) with an unknown collider, now concealed beneath younger cover to the east. Exhumation of at least a 15 km crustal thickness within only a few million years indicates a short period of collisional orogenesis, consistent with the observed metamorphic evidence for a low thermal gradient during crustal thickening. Tectonic uplift and erosion of the Nimbuwah Complex fed the retro-arc Cosmo Supergroup and possibly other Paleoproterozoic successions of the North Australian Craton that are dominated by c. 1870 Ma detritus. The low thermal gradient in overthickened crust, which is unusual for Proterozoic Australia, might be a consequence of collision between relatively cool, rigid Archean blocks.

Nolans Bore is a REE-U-P deposit (47 Mt grading 2.6% REO, 186 ppm U3O8 and 11% P2O5) hosted by apatite veins and breccias within the ~1805 Ma Boothby Orthogneiss of the Aileron Province, Northern Territory. Allanite SHRIMP U-Pb analyses indicate a vein crystallisation age of 1525±40 Ma, but mineral system processes necessary to the development of the deposit commenced before 1800 Ma and continue today. Processes leading to the formation of Nolans Bore began with north-dipping subduction along the south margin of the Aileron Province at 1820-1750 Ma, producing a metasomatised, volatile-rich lithospheric mantle wedge. About 200 Ma later, towards the end of the Chewings Orogeny, this reservoir became a source of alkaline low-degree partial melts which passed into the mid- and upper-crust. Among these alkaline products was a phosphate-rich magmatic-hydrothermal fluid which deposited the Nolans Bore apatite veins by local fluid-rock interaction and/or fluid mixing at ~400 degrees C. The deposit then became a radiogenic heat source, owing to its size and high concentration of Th, raising the local ambient temperature to ~300 degrees C, above the closure temperature of some mineral isotopic systems. For example, vein apatite U-Pb ages are in the range ~1240 to ~960 Ma, significantly younger than initial emplacement. The system finally cooled below 300 degrees C (the 40Ar-39Ar closure temperature of biotite) at ~370 Ma, possibly in response to unroofing during the Alice Springs Orogeny. Subsequent to surface exposure, weathering of fluorapatite produced acidic fluids and intense, near-surface kaolinitised zones that form high-grade, supergene-enriched cheralite-rich ores. This groundwater-mediated process continues today. The local heat production of Th- and/or U-rich deposits is an important feature that may be partly responsible for the arrays of post-emplacement isotopic ages which characterise such mineral systems. Other physical and chemical processes continue to be generated by the high abundances of reactive and heat-producing elements at Nolans Bore, with significant effects on the economic, isotopic and geochemical characteristics of the deposit and its host, an observation that may apply to other such deposits.

Baseline information on biodiversity and habitats is required to manage Australia's northern tropical marine estate. This study aims to develop an improved understanding of seafloor environments of the Timor Sea. Clustering methods were applied to a large dataset comprising physical and geochemical variables which describe organic matter (OM) reactivity/quantity/source and geochemical processes. Infauna data were used to assess different groupings. Clusters based on physical/geochemical data discriminated infauna better than geomorphic features. Major variations amongst clusters included grainsize and a cross-shelf transition in from authigenic-Mn /As enrichments (inner shelf) to authigenic-P enrichment (outer shelf). Groups comprising raised features had the highest reactive OM concentrations (e.g. low chlorin indices and C:N-ratios, and high k) and benthic algal '13C signatures. Surface area normalised OM concentrations higher than continental shelf norms were observed in association with: (i) low -15N, inferring Trichodesmium input; and (ii) pockmarks, which impart bottom-up controls on seabed chemistry and cause inconsistencies between bulk and pigment OM pools. Low Shannon-Wiener diversity occurred in association with low redox and porewater pH and evidence for high energy. Highest beta-diversity was observed at euphotic depths. Geochemical data and clustering methods used here provide insight into ecosystem processes influencing biodiversity patterns in the region.

The Australian Government, through the Department of Resources, Energy and Tourism, has supported Geoscience Australia in undertaking a series of regional-scale, geological studies to assess the CO2 storage potential of sedimentary basins, including the Petrel Sub-basin. The studies form part of the National Low Emissions Coal Initiative designed to accelerate the development of CO2 transport and storage infrastructure near the sources of major energy and industrial emissions. The Petrel Sub-basin was identified as a high-priority region for a future pre-competitive work program by the national Carbon Storage Taskforce. The Carbon Storage Taskforce also recommended the release of greenhouse gas assessment permits, which were released within the Petrel Sub-basin in 2009. As a component of the studies at Geoscience Australia, the numerical simulation was hypothetically designed to dynamically model the reservoir behavior and CO2 migration during the injection and post-injection stages using an in-house built 3D geological model of a represented injection site. 14 million tonnes per annum (MTPA) of CO2 was injected into the lower Frigate/Elang/Plover reservoir over 30 years and CO2 plume migration was simulated up to 2,000 years from the initial injection. The injection rate of 14 MTPA of CO2 used in this study was based on the predicted 2020 CO2 emissions of the Darwin Hub, a figure defined by the Carbon Storage Taskforce (2009). The poster highlights the simulation results including CO2 plume migration distance, CO2 trapping mechanisms and reservoir pressure behavior.

The ca. 1.4 Ga Roper Group of northern Australia comprises the sedimentary fill of one of the most extensive Precambrian hydrocarbon-bearing basins preserved in the geological record. It is interpreted to have been deposited in a large epeiric sea known as the Roper Seaway. This study presents hydrocarbon biomarkers, high-resolution trace element redox geochemistry and neodymium isotopes of immature to mature black shales to understand the microbial diversity and palaeo-environment of the Roper Seaway.

The ecosystems of northern Australia have very high global rankings in terms of the estimated dollar values of the ecosystem services they provide. Estuaries, which are abundant along the northern Australia coast, are some of the most productive ecosystems on earth, and provide vital nursery habitat for economically important species of fish and crustaceans. Most of the world's population lives in close proximity to estuaries therefore they also tend to be amongst the most degraded marine ecosystems on the planet. However, due to the small population sizes, most of Northern Australia's estuaries are unique in the respect that they are in near-pristine condition. One of the key triggers in estuarine productivity is the fresh water inflow received during the wet season and the flow recession periods afterward. To date there have been no studies of the environmental flow requirements for estuaries in the Northern Territory. As northern Australia develops there will be greater reliance on these important ecosystems for food production and recreation, while at the same time there will be competing demands for freshwater. The designation of environmental flows to river-estuary systems should be based on estuary requirements. If adequate estuarine environmental flows are maintained then it is likely that flows in upper river reaches will also be sufficient for riverine species. Studies of the roles of environmental flows on productivity in estuaries in catchments slated for development will be key in providing the foundation for economically and ecologically sustainable development of these important ecosystems. These studies will also provide additional information on how other uses of estuaries may be developed. For example wetland systems may be used for aquaculture or as watering points. Good information on estuarine processes will not only provide previously unexplored opportunities but help to ensure that our estuaries remain in excellent condition.

A geochemical orientation study in the Davenport Province, Northern Territory, indicates that stream-sediment sampling is an effective geochemical technique for mineral assessment, despite overall poor drainage development. Bismuth, Mo , Sn and W from vein-type deposits appear to be dispersed by mechanical weathering, giving rise to well-defined anomalies in both sieved samples and heavy mineral concentrates. Dispersion trains exceed 10 km downstream from mineralisation, and for regional surveys the analysis of a coarse sieved fraction at a sample spacing of 1 to 2 km is recommended. Dispersion of U and Cu appears to be chemically controlled, and anomalies near known mineralisation in both sieved and heavy mineral samples are either less well defined or absent. Dispersion trains rarely extend more than 1 km from mineralisation , and sample spacing of 0.5 to 1 km, or less, would be necessary.

Approximately 25,000 water bores are registered under the Northern Territory Water Act. Entry of bore data (including water quality data) into a computer data set has been proceeding for several years. Sufficient entered data for meaningful statistical output is only available for the arid (southern) zone. Preliminary examination of the status of arid zone bores indicates that, while failure to obtain adequate yield is the major reason for unsuccessful drilling, unsuitable water quality has resulted in the rejection of 26% of bores obtaining an otherwise sufficient supply for community water supply purposes.

Gosses Bluff consists of a prominent circular ridge, 4.5 km in diameter, surrounded by a less well-exposed deformed outer ring, 24 km in diameter, which incorporates annular breccia troughs. The circular ridge, which forms part of an eroded central uplift, is composed of fractured and brecciated Ordovician to Devonian sandstone and shale, capped in places by overturned megabreccia. The structure was formed by the impact of an asteroid or comet. Evidence for an extraterrestrial impact origin includes: (1) the circular symmetry of the disturbed zone, which comprises outcrops of vertical to overturned strata whose original stratigraphic position would be at depths of <3-4 km; (2) the presence of shatter cones and rhomboidal fracture patterns diagnostic of intense shock; (3) shatter-cone axes that define a structurally central focus at shallow depth beneath the palaeosurface when reconstructed to their pre-impact orientation; (4) outward ejection of large blocks; (5) melting of sandstone and siltstone to form melt breccia; (6) a gradation with increasing depth from shock-melted breccia into recrystallised and unheated breccia, suggesting a high central heat source; (7) a depth limit of the structural disturbance defined by continuous seismic reflectors below about 3500 m; (8) the absence of gravity anomalies which would provide evidence for deep-seated mass excess or deficiency. Mineralogical and microstructural features diagnostic of instantaneously applied shock pressures abound. Quartz in both breccia and bed-rock shows shock-induced fractures and planar deformation features. The melt breccia at Mount Pyroclast records higher shock levels: quartz has been transformed to glass, partly recrystallised into tridymite, and subsequently converted to solid-state diaplectic quartz. The fusion of shale resulted in potassium-enriched hot solutions circulating below the crater floor, and recrystallisation into pumiceous aggregates of sanidine accompanied by zeolites and hematite. Ar-Ar plateau ages of this sanidine-rich material suggest recrystallisation at 142.5 ± 0.8 Ma, which - along with the orientation and reverse nature of the geomagnetic field at the time of the event - points to a latest Jurassic age. Calculations indicate that a crater the diameter of the Gosses Bluff structure reflects the release of energy in the order of 105_106 Mt, which could have been generated by an asteroid or comet estimated to have been about 2 km in diameter.