The Archean Yilgarn Craton of Western Australia, is not only one of the largest extant fragments of Archean crust in the world, but is also one of the most richly-mineralised regions in the world. Understanding the evolution of the craton is important, therefore, for constraining Archean geodynamics, and the influence of such on Archean mineral systems. The Yilgarn Craton is dominated by felsic intrusive rocks - over 70% of the rock types. As such these rocks hold a significant part of the key to understanding the four-dimensional evolution of the craton, providing constraints on the nature and timing of crustal growth, the role of the mantle, and also the timing of important switches in crustal growth geodynamics. The granites also provide constraints on the nature and age of the crustal domains within the craton. Importantly, this crustal pre-history appears to have exerted a significant, but poorly understood, spatial control on the distribution of mineral systems, such as gold, komatiite-associated nickel sulphide and volcanic-hosted massive sulphide (VHMS) base metal systems

The development of a regional stratigraphy in Palaeoproterozoic basins within the Tanami region, Northern Australia has been hindered by the difficulty of discriminating sedimentary units and facies across isolated and poorly exposed basins. A regional stratigraphy is important as it provides constraints on sedimentary basin evolution and assists in gold exploration, as mineralisation is more abundant in certain rock formations. Based on geochemistry, five main sedimentary basin events have been identified in the Tanami region, ranging from poorly mixed local sedimentary sources to well mixed distal sources. Within the basins, major gold bearing lithologies are characterised by mafic source indicators: (1) high Cr/Th ratios; (2) low Th/Sc ratios; (3) low (La/Yb)N ratios relative to Post-Archaean Average Shale; (4) Eu anomaly equal to ~1 and, (5) distinctive ranges in initial Nd values, which together define vertical stratigraphic position. Potential future exploration target areas have been identified in the Tanami region at the Cashel and Sunline prospects using these geochemical parameters.

The New England Orogen (NEO) forms the easternmost part of continental Australia, being one of a number of identified orogenic belts within the Tasman Orogenic Zone of eastern Australia. The NEO borders parts of the Lachlan, Thomson and North Queensland Orogens (see Fig. 1), though actual contacts are largely obscured by the Sydney-Gunnedah-Bowen basin system and other cover rocks. The NEO consists of a collage of terranes and has a complex history that stretches from the Neoproterozoic to the Late Mesozoic, although most of the exposed geology is Devonian and younger. A major characteristic of the NEO in this convergent margin setting is the voluminous Carboniferous to Triassic magmatism, which forms a major component of the orogen. Importantly, this magmatism is not confined to the NEO. Carboniferous to mid Triassic felsic magmatism (ca. 350-220 Ma) (Post-Kanimblan Orogeny to Hunter-Bowen Orogeny) forms a major part of the Tasman Orogenic Zone, extending in a wide belt from central New South Wales (the Bathurst region) to islands within the Torres Straits, straddling the Lachlan, Thomson, New England and North Queensland Orogens (Fig. 1), as well as extending into the Proterozoic basement west of the Tasman Orogenic Zone in northern Queensland (Fig. 1). As such, the geochemical and isotopic characteristics of these magmatic rocks, and their regional variations, have the potential to provide significant information regarding the nature and age of the crust in these orogens, as well as to provide constraints on the relationship of the development of the NEO to the neighbouring orogens.

The carbon and hydrogen isotopic data of natural gases provide a crucial tool to interpret the origin, occurrence and inter-relationships of natural gases. The CF-GC-IRMS is a convenient system to separate gas mixture and obtain continuous, on-line isotopic data of individual compounds. With CF-GC-IRMS system, the abundance of target components is crucial. For an accurate result, there should be enough target compound going through the furnace to be measured as CO2 using isotopic ratio mass spectrometry. For carbon isotopes, a m/z 44 response below 0.3 V (or over 7V) is regarded as unreliable. For high abundant compounds, there is no difficulty in attaining a voltage over 0.3V with a normal injection of under 100ul with adjusted split flow. However, the acquisition for the low concentration component is problematic since "normal" injection would not produce a strong enough signal. In this presentation, we demonstrated the techniques used to obtain low concentration components occurring in the Australian natural gases and how we apply the results in gas comparison studies. Cryogenics (liquid nitrogen trap) is applied to trap and concentrate low amount of compounds other than methane (C1), including CO2, C2 and above. With this method, extreme low concentration of C2 from very dry gases was obtained with large volume injection of 10ml. Back-flash is used together with cryogenics. For analyses for only C4 and C5 compounds, cryogenics was not needed, since they focus at the front of the column at 40oC and elute from the column under oven temperature programming as single peaks. Neo-pentane (neo-C5) is generally the least abundant wet gas component. Its concentration is enhanced in the gases which are biodegraded, wherein the other gas components have been selectively removed by microbial activity. Neo-pentane is extremely resistant to biodegradation and shows no isotopic alteration even in severely biodegraded gas. In such cases, neo-C5 is the only gas component that can be confidently used in gas-gas correlation. Neo-pentane is an example where we employ injection of a large volume (e.g. to 40ml for hydrogen isotopes), combining a back-flashing technique for compounds eluting before C4 (inclusive) and C5 compounds. The neo-C5 elutes between nC4 and i-C5. Under the current GC conditions, there is a time "window" of less than 40 seconds to capture neo-C5. A manual operation to set back-flash to straight flow to allow capture neo-C5 just after n-C4 elutes and then back to back-flush to eliminate interference of C5's compounds. Mass balance estimation indicates that there is no loss of neo-C5 during the large volume injection and repeatability is excellent.

The Kingoonya Palaeovalley is one of the largest arid zone palaeovalley systems in South Australia. Situated in the remote central-western Gawler Craton this relict drainage network, now buried and obscured by surficial Quaternary sediments, is characterised by multiple headwater tributaries which flowed predominantly westwards towards the Eucla Basin. Fluvial and lacustrine sediments infilling the incised palaeovalley, in places forming stacked sequences >100 metres thick, were sporadically deposited from the Mid Eocene to the Early Pliocene. Previous drilling transects indicated a variety of channel shapes and heterogeneous sediment packages, with favourable aquifer sequences (sand-rich) common in deeper parts. In 2010 detailed groundwater sampling from existing bores was conducted in the Kingoonya Palaeovalley for the National Water Commission-funded Palaeovalley Groundwater Project. Analysis of these samples indicates that most Kingoonya groundwaters are moderately to highly saline and dominated by Na and Cl ions. Trace element enrichments are uncommon, although locally elevated levels of some metals (e.g., Fe and Mn) likely reflect groundwater interactions with the heterogenous sediments. The Kingoonya groundwaters also have near-neutral to slightly acidic pH, low alkalinity and are mostly oxidising. Stable water isotopes define a distinct trend away from the LMWL, interpreted as multiple stages of evaporative recycling and relative enrichment from the original isotopic signatures (precipitation derived from nearby Southern Ocean). Radiocarbon ages indicate a spectrum of groundwater residence times, ranging from modern recharge to groundwater signatures >20,000 years in deeper parts of the basal palaeovalley aquifer.

The natural gases are composed of a limited number of individual compounds, mainly of C1-C5 hydrocarbons and non-hydrocarbon compounds (CO2, N2, noble gases etc.). Their compositions and isotopes of single compounds provide critical information to decipher the origin and evolution of natural gases. Efficient analysis of these compounds is paramount for timely application of this important dataset.

Devonian-Carboniferous granites are widespread in Tasmania. In the east they intrude the Ordovician-Early Devonian quartzwacke turbidites of the Mathinna Supergroup, whereas the western Tasmanian granites intrude a more diverse terrane of predominantly shelf sequences, with depositional ages extending probably back to the Late Mesoproterozoic. The earliest (~400 Ma) I-type granodiorites in the east may be arc-related and pre-date the Tabberabberan Orogeny (~388 Ma), which appears to represent the juxtaposition of the two terranes. Subsequently more felsic and finally strongly fractionated I- and S-type granites were emplaced until ~373 Ma. In western Tasmania, mostly felsic and fractionated I- and S-types granites were emplaced from ~374-351 Ma, possibly in response to back-arc or post-collisional crustal extension

Aspects of the tectonic history of Paleo- to Mesoproterozoic Australia are recorded by metasedimentary basins in the Mt Isa, Etheridge Provinces, and Coen Inlier in northern Australia and in the Curnamona Province of southern Australia. These deformed and metamorphosed basins are interpreted to have been deposited in a tectonically-linked system based on similarities in depositional ages and stratigraphy (Giles at al 2002). Neodymium isotope compositions of sediments and felsic volcanics, when combined with U-Pb geochronology, are independent data that are important tools for inferring tectonic setting, palaeogeography and sediment provenance in deformed and metamorphosed terrains.

Single-copounds carbon isotops of Precambrian eviporates.

Metallogenic, geologic and isotopic data indicate secular changes in the character of VHMS deposits relate to changes in tectonic processes, tectonic cycles, and changes in the hydrosphere and atmosphere. The distribution of these deposits is episodic, with peaks at 2740-2680 Ma, 1910-1840 Ma, 510-460 Ma and 370-355 Ma that correspond to the assembly of Kenorland, Nuna, Gondwana and Pangea. Quiescent periods of VHMS formation correspond to periods of supercontinent stability. Large ranges in source 238U/204Pb that characterize VHMS deposits in the Archean and Proterozoic indicate early (Hadean to Paleoarchean) differentiation. A progressive decrease in - variability suggests homogenisation with time of these differentiated sources. Secular increases in the amount of lead and decreases in 100Zn/(Zn+Pb) relate to an increase in felsic-dominated sequences as hosts to deposits and an absolute increase in the abundance of lead in the crust with time. The increase in sulfate minerals in VHMS deposits from virtually absent in the Meso- to Neoarchean to relatively common in the Phanerozoic relates to oxidation of the hydrosphere. Total sulfur in the oceans increased, resulting in an increasingly important contribution of seawater sulfur to VHMS ore fluids with time. Most sulfur in Archean to Paleoproterozoic deposits was derived by leaching rocks below deposits, with little contribution from seawater, resulting in uniform, near-zero-permil values of 34Ssulfide. In contrast the more variable values of younger deposits reflect the increasing importance of seawater sulfur. Unlike Meso- to Neoarchean deposits, Paleoarchean deposits contain abundant barite, which is inferred to have been derived from photolytic decomposition of atmospheric SO2 and does not reflect overall oxidised oceans. Archean and Proterozoic seawater was more salty than Phanerozoic, particularly upper Phanerozoic, seawater. VHMS fluids ore fluids reflect this, also being saltier in Precambrian deposits.