The Brattstrand Paragneiss, a highly deformed Neoproterozoic granulite-facies metasedimentary sequence, is cut by three generations of ~500 Ma pegmatite. The earliest recognizable pegmatite generation, synchronous with D2-3, forms irregular pods and veins up to a meter thick, which are either roughly concordant or crosscut S2 and S3 fabrics and are locally folded. Pegmatites of the second generation, D4, form planar, discordant veins up to 20-30 cm thick, whereas the youngest generation, post-D4, form discordant veins and pods. The D2-3 and D4 pegmatites are abyssal class (BBe subclass) characterized by tourmaline + quartz intergrowths and boralsilite (Al16B6Si2O37); the borosilicates prismatine, grandidierite, werdingite and dumortierite are locally present. In contrast, post-D4 pegmatites host tourmaline (no symplectite), beryl and primary muscovite and are assigned to the beryl subclass of the rare-element class. Spatial correlations between B-bearing pegmatites and B-rich units in the host Brattstrand Paragneiss are strongest for the D2-3 pegmatites and weakest for the post-D4 pegmatites, suggesting that D2-3 pegmatites may be closer to their source. Initial 87Sr/86Sr (at 500 Ma) is high and variable (0.7479-0.7870), while -Nd500 tends to be least evolved in the D2-3 pegmatites (-8.1 to -10.7) and most evolved in the post-D4 pegmatites (-11.8 to -13.0). Initial 206Pb/204Pb and 207Pb/204Pb and 208Pb/204Pb ratios, measured in acid-leached alkali feldspar separates with low U/Pb and Th/Pb ratios, vary considerably (17.71-19.97, 15.67-15.91, 38.63-42.84), forming broadly linear arrays well above global Pb growth curves. The D2-3 pegmatites contain the most radiogenic Pb while the post-D4 pegmatites have the least radiogenic Pb; data for D4 pegmatites overlap with both groups. Broad positive correlations for Pb and Nd isotope ratios could reflect source rock compositions controlled two components. Component 1 (206Pb/204Pb-20, 208Pb/204-43, Nd -8) most likely represents old upper crust with high U/Pb and very high Th/Pb. Component 2 (206Pb/204Pb -18, 208Pb/204Pb~38.5, -Nd500 -12 to -14) has a distinctive high-207Pb/206Pb signature which evolved through dramatic lowering of U/Pb in crustal protoliths during the Neoproterozoic granulite-facies metamorphism. Component 1, represented in the locally-derived D2-3 pegmatites, could reside within the Brattstrand Paragneiss, which contains detrital zircons up to 2.1 Ga old and has a wide range of U/Pb and Th/Pb ratios. The Pb isotope signature of component 2, represented in the 'far-from-source' post-D4 pegmatites, resembles feldspar Pb isotope ratios in Cambrian granites intrusive into the Brattstrand Paragneiss. However, given their much higher 87Sr/86Sr, the post-D4 pegmatite melts are unlikely to be direct magmatic differentiates of the granites, although they may have broadly similar crustal sources. Correlation of structural timing with isotopic signatures, with a general sense of deeper sources in the younger pegmatite generations, may reflect cooling of the crust after Cambrian metamorphism.

Legacy product - no abstract available

The Browse Basin lies offshore from Western Australia's Kimberley region and hosts vast accumulations of natural gas, some of which are rich in condensate, making it Australia's next major liquefied natural gas (LNG) producing province on the North West Shelf. The Ichthys accumulation is estimated to host 12.8 trillion cubic feet (Tcf) of gas and 527 million barrels (mmbbl) of condensate (condensate:gas ratio (CGR) 60 bbl/MMscf) representing the largest hydrocarbon accumulation with recoverable liquids found in Australia since the discovery of the Gippsland Basin and Barrow Island oil fields in the 1960s. Similar amounts of gas, albeit drier (CGR 2030 bbl/MMscf) are hosted within the Brecknock, Calliance and Torosa accumulations (cumulative 15.9 Tcf gas, 436 mmbbl condensate). Despite the extensive ongoing exploration activity and prior research interest [1, 2 and 3], the basin's petroleum systems (PS) have not been publically updated for a decade. Collating the existing molecular and isotopic datasets for the wet gases and associated hydrocarbon liquids, along with the biomarker and 13C/12C and D/H ratios of the n-alkanes for the crude oils, has enabled the origin and extent of the petroleum systems to be redefined. In doing so, it is apparent that the filling of the gas accumulations within the Caswell Sub-basin and along the Scott Reef-Brecknock trend is complex, with the component gases originating from multiple organic and inorganic sources. Differing degrees of biodegradation are observed in the Cornea and Gwydion oil and gas accumulations. Four preliminary petroleum systems are defined for known accumulations by their 13C n-alkane isotopic profiles (Figure 1). The PloverPlover PS is a basin-wide gas-prone system where the gas is reservoired within the Middle Jurassic Plover Formation (e.g. Brecknock-Torosa, Ichthys) and sourced from mixed terrestrial and marine organic matter deposited in fluvio-deltaic sediments. The Plover/VulcanVulcan PS occurs within the central Caswell Sub-basin at Ichthys and Prelude/Concerto and is a wet gas-prone system reservoired within the Upper Jurassic Brewster Member, upper Vulcan Formation. This PS has a more marine source affinity with the additional hydrocarbons probably being sourced from the lower Vulcan Formation. The Plover/VulcanPlover/Vulcan/Nome PS is a gas-prone system within the Heywood Graben. The complex reservoir at Crux is sourced from mixed terrestrial and marine organic matter deposited that may be sourced from within Jurassic sediments. The Echuca ShoalsHeywood PS is an oil- and gas-prone system (e.g. Caswell, Cornea and Gwydion) sourced by marine algae and bacterial remains within Lower Cretaceous sediments [2]. The oils and gases on the Yampi Shelf vary in their degree of biodegradation. Further work is in progress to confirm these petroleum systems and redefine their extent by correlating the wet gases and oils with their source rocks.

Geoscience Australia and CO2CRC have constructed a greenhouse gas controlled release reference facility to simulate surface emissions of CO2 (and other GHG gases) from an underground slotted horizontal well into the atmosphere under controlled conditions. The facility is located in a paddock maintained by CSIRO Plant and Industry at Ginninderra, ACT. The design of the facility is modelled on the ZERT controlled release facility in Montana, which conducts experiments to develop capabilities and test techniques for detecting and monitoring CO2 leakage. The first phase of the installation is complete and has supported an above ground, point source, release experiment, utilising a liquid CO2 storage vessel (2.5 tonnes) with a vaporiser, mass flow controller unit with a capacity for 6 individual metered gas outlet streams, equipment shed and a gas cylinder cage. Phase 2 involved the installation of a shallow (2m depth) underground 120m horizontally drilled slotted well, in June 2011, intended to model a line source of CO2 leakage from a storage site. This presentation will detail the various activities involved in designing and installing the horizontal well, and designing a packer system to partition the well into six CO2 injection chambers. A trenchless drilling technique used for installing the slotted HDPE pipe into the bore hole will be described. The choice of well orientation based upon the effects of various factors such as topography, wind direction and ground water depth, will be discussed. It is envisaged that the facility will be ready for conducting sub-surface controlled release experiments during spring 2011.

Legacy product - no abstract available

The Habanero Engineered Geothermal System (EGS) in central Australia has been under development since 2002, with several deep (more than 4000 m) wells drilled into the high-heat-producing granites of the Big Lake Suite to date. Multiple hydraulic stimulations have been performed to improve the existing fracture permeability in the granite. The stimulation of the newly-drilled Habanero-4 well (H-4) was completed in late 2012, and micro-seismic data indicated an increase in total stimulated reservoir area to approximately 4 km². Two well doublets have been tested, initially between Habanero-1 (H-1) and Habanero-3 (H-3), and more recently, between H-1 and H-4. Both doublets effectively operated as closed systems and excluding short-term flow tests, all production fluids were re-injected into the reservoir at depth. Two inter-well tracer tests have been conducted since 2008, to evaluate the fluid residence time in the reservoir alongside other hydraulic properties, and to provide comparative information to assess the effectiveness of the hydraulic stimulations. The closed-system and discrete nature of this engineered geothermal reservoir provides a unique opportunity to explore the relationships between the micro-seismic, rock property, production and tracer data. The most recent inter-well tracer test occurred in June 2013, which involved injecting 100 kg of 2,6 naphthalene-disulfonate (NDS) into H-1 to evaluate the hydraulic characteristics of the newly-created H-1/H-4 doublet. Sampling of the production fluids from H-4 occurred throughout the duration of the 3-month closed-circulation test. After correcting for flow hiatuses (i.e. interruptions in injection and production) and non-steady-state flow conditions, tracer breakthrough in H-4 was observed after 6 days (compared to ~4 days for the previous H-1/H-3 doublet), with peak breakthrough occurring after 17 days. Applying moment analysis to the data indicated that approximately 56% of the tracer was returned during the circulation test (vs. approximately 70% from the 2008 H-1/H-3 tracer test). This suggests that a considerable proportion of the tracer may lie trapped in the opposite end of the reservoir from H-4 and/or may have been lost to the far field. Flow capacity:storage capacity plots derived from the H-1/H-4 tracer test indicate that the Habanero reservoir is moderately heterogeneous, with approximately half of the flow travelling via around 25% of the pore volume. The calculated inter-well swept pore volume was approximately 31,000 m³, which is larger than that calculated for the H-1/H-3 doublet (~20,000 m³). This is consistent with the inferred increase in reservoir volume following hydraulic stimulation of H-4.

This keynote address was presented at the Australian Nickel Conference held in Perth, 13-14 October 2004. Nickel-sulphide deposits in Australia are mainly associated with Archaean komatiites and Archaean Proterozoic mafic intrusions, but some unusual Phanerozoic deposits occur in eastern Australia. The majority of Australia's nickel production (~80%) is derived from komatiite deposits in the Yilgarn Craton of Western Australia. The Eastern Goldfields Province of this craton hosts one of the greatest concentrations of Archaean komatiite-hosted nickel deposits in the world, several of which are world class (>1 Mt Ni). Exploration activities in Australia are currently focussed on mafic-ultramafic rocks in Late Archaean and Proterozoic provinces. Exploration has been stimulated by the discovery of new deposits (Flying Fox, Daybreak, Armstrong, Daltons, McEwen, Nebo-Babel), recognition of different styles of mineralisation (Avebury), and the protracted period of elevated nickel metal prices. There is considerable potential for finding new deposits associated with komatiites and mafic intrusions, particularly under shallow cover. Geoscience Australia has undertaken new research initiatives that define favourable mineralising elements, exploration strategies, and new nickel metallogenic provinces.

February 2001 Bonaparte Basin - Gas Data The gas database contains molecular compositional and isotopic data for gases from the Bonaparte Basin as exported from AGSO's Orgchem database on 6th February 2001. The output represents those gases for which the data is considered not to be "commercial-in-confidence". Also included is a document which gives a description of the data fields. Copyright (C) Commonwealth of Australia, 2000.

Archaean TTGs, as originally defined comprise intermediate to felsic rocks characterised by high Na2O/K2O, low to moderate LILE contents and no potassium-enrichment with increasing differentiation. The majority of such rocks also carry a high-pressure signature, identified by elevated Sr (i.e., are Sr-undepleted) and Eu, fractionated REEs, with low HREE (Y- and HREE-depleted), and high Sr/Y. These latter characteristics are also often used to define TTGs and are commonly thought to reflect an origin via slab melting (with or without mantle-wedge interaction), largely as a necessary corollary of a warmer Archaean mantle. Our work, however, shows that within many Archaean terranes there exists a subclass of granites (which we call transitional TTGs), that when compared to `true? TTGs have higher LILE contents, show strong enrichment in LILEs (e.g., K2O) with increasing differentiation, and tend towards more siliceous compositions (68-77% SiO2), but still possess a similar high-pressure signature. Such transitional TTGs are contemporaneous with, or postdate true TTGs but where present also grade to more mafic compositions that overlap with true TTGs. These Transitional TTGs dominate some cratons, the best example being the Yilgarn Craton where true TTGs form only a small percentage of total granites. Sm-Nd isotopic and inherited zircon data indicate that the petrogenesis of most transitional TTGs requires the involvement of pre-existing crust. What is not clear, given the difficulty in reconstructing tectonic environments in the Archaean, is whether this crustal component represents input via the subduction process (e.g., subducted sediments), represents a response to thicker pre-existing crust (AFC processes), or whether these rocks form from pure crustal melts in thickened Archaean crust. Comparison of both TTG-types with ?apparent? modern-day TTG analogues ? adakites ? shows somewhat similar groupings. The major adakite group (group 1, mostly 58-68% SiO2), is characterised by a narrow range in La/Sm (5.5-3.0), and Sm/Yb (1.5-3.5), moderate Sr (400-700 ppm) and low to moderate LILE. This group overlaps significantly with true TTGs although the latter tend to have higher La/Sm (up to 9) and Sm/Yb (up to 10+). The second adakite group has higher Sm/Yb (6-10), La/Sm (6-9) and Sr (<500 to 1500 ppm), and typically higher LILE contents, and appears to be confined to continental arc regimes and is most similar to transitional TTGs. Notably both TTG-types extend to significantly more silica and LILE-rich compositions than seen in the majority of adakites. A distinctive, significantly more mafic (50-60+% SiO2) adakite group with high to very high Sr (up to 1500-2500 ppm), and high Sm/Yb (to 10-12), appears distinct from all Archaean TTGs. Group 1 adakites are most consistent with melting of a MORB source leaving an amphibole-bearing (i.e., non-eclogitic) residue, while group 2 adakites are interpreted to represent either melting at higher pressure or greater degrees of slab melting (leaving an eclogitic residue), with their higher LILE contents reflecting either subducted sediment input or processes related to the presence of continental crust (e.g., AFC). In contrast, the range in La/Sm and Sm/Yb in true TTGs suggests greater involvement of garnet during melting in Archaean times (garnet amphibolite to eclogite residue) relative to modern day (group 1) adakites, perhaps reflecting a greater depth of generation or drier melting. Importantly, although pure crustal melting can not be ruled out, analogies with group 2 adakites shows that transitional TTGs can be produced as slab melts particularly in continental arc environments ? both models maybe applicable and may have varied in relative importance through time. Further, the presence of transitional TTGs in Archaean cratons can be used to infer significant pre-existing continental crust. (THIS ABSTRACT MODIFIED FROM ORIGINAL).

Data gathered in the field during the sample collection phase of the National Geochemical Survey of Australia (NGSA) has been used to compile the Preliminary Soil pH map of Australia. The map, which was completed in late 2009, offers a first-order estimate of where acid or alkaline soil conditions are likely to be expected. It provides fundamental datasets that can be used for mineral exploration and resource potential evaluation, environmental monitoring, landuse policy development, and geomedical studies into the health of humans, animals and plants.