Lord Howe Island is a small, mid-ocean volcanic and carbonate island in the southwestern Pacific Ocean. Skeletal carbonate eolianite and beach calcarenite on the island are divisible into two formations based on lithostratigraphy. The Searles Point Formation comprises eolianite units bounded by clay-rich paleosols. Pore-filling sparite and microsparite are the dominant cements in these eolianite units, and recrystallised grains are common. Outcrops exhibit karst features such as dolines, caves and subaerially exposed relict speleothems. The Neds Beach Formation overlies the Searles Point Formation and consists of dune and beach units bounded by weakly developed fossil soil horizons. These younger deposits are characterised by grain-contact and meniscus cements, with patchy pore-filling micrite and mirosparite. The calcarenite comprises several disparate successions that contain a record of up to 7 discrete phases of deposition. A chronology is constructed based on U/Th ages of speleothems and corals, TL ages of dune and paleosols, AMS 14C and amino acid racemization (AAR) dating of land snails and AAR whole-rock dating of eolianite. These data indicate dune units and paleosols of the Searles Point Formation were emplaced during oxygen isotope stage (OIS) 7 and earlier in the Middle Pleistocene. Beach units of the Neds Beach Formation were deposited during OIS 5e while dune units were deposited during two major phases, the first coeval with or shortly after the beach units, the second later during OIS 5 (e.g. OIS 5a) when the older dune and beach units were buried. Large-scale exposures and morphostratigraphical features indicate much of the carbonate was emplaced as transverse and climbing dunes, with the sediment source located seaward of and several metres below the present shoreline. The lateral extent and thickness of the eolianite deposits contrast markedly with the relatively small modern dunes.

As recognised by the Academy of Science's UNCOVER group in their `Searching the Deep Earth' document, a goal for geoscientific advancement in Australia is a `holistic understanding of our continent so that we might better predict the location of large-scale mineral systems. This view included the investigation of Australia's lithospheric architecture to establish a whole-of-lithosphere architectural framework as a priority. An important component of the Earth's lithosphere is the crust, most of which is clearly inaccessible. Just as the study of basaltic rocks has provided insight into the earth's mantle, granites provide a (not always wholly transparent) window into the middle and lower continental crust. Studies of these rocks are enhanced by isotopic tracers, such as Samarium-Neodymium, which can affectively `see through' the granite to provide constraints on crustal formation, and enable us to map the Australian crust. This approach and the application of Samarium-Neodymium isotope data were used by Geoscience Australia for the Archean Yilgarn Craton of Western Australia. Studies in that region showed that regional scale Samarium-Neodymium signatures in felsic igneous rocks (tonalite to granite and volcanic equivalents) were not only able to map crustal architecture but that this architecture had unexpected correlations with mineralisation. The successful results in the Yilgarn Craton, coupled with the UNCOVER focus, warranted that this approach be extended to the whole of the continent to test its general applicability for crustal mapping and predicting mineralisation. A database of Sm-Nd isotopic data, and associated metadata, for >2650 samples of Australian rocks was compiled from published and unpublished sources. This included location, unit, geochronology and bibliographic data and metadata for all data points; this dataset is available for download at www.ga.gov.au. Data were compiled for a range of lithologies, including felsic and mafic igneous rocks, sedimentary rocks, as well as some mineral data. Just over 1630 of these data points were from felsic igneous rocks which had reliable locational details and a reasonable estimated or known magmatic age. A comparison of the magmatic ages from these samples with compilations of Australian igneous rock ages showed a generally good agreement confirming the representative nature of the compiled Nd data set.

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.

Natural gas is Australia's third largest energy resource after coal and uranium but despite this economic importance, the gas origin is not always recognized. To address this, isotope and geochemistry data have been collated on 850 natural gases from all of Australia's major gas provinces with proposed source ages spanning the earliest Paleozoic to the Cenozoic. Unaltered natural gases have a thermogenic origin ('13C methane ranges between -49 and -27'; 'D methane ranges between -290 and -125'). Microbially altered natural gases were identified primarily on the basis of 13C and D enrichments in propane and/or 13C depletion in methane and/or 13C enrichment in CO2. The carbon isotopic composition of the gas source has been estimated using '13C iso-butane as a surrogate for '13C kerogen while for gases where biodegradation is moderate to severe, '13C neo-pentane provides an alternative measure. The '13C kerogen of gas source rocks range from -47 to -22' with the older Paleozoic sources and marine kerogen amongst the most depleted in 13C. The '13C CO2 also provides an insight into crustal- and mantle-derived components while '15N N2 (-6.0 to 2.3' for N2 up to 47 %) distinguish between organic and inorganic (groundwater) inputs. This dataset provides a better understanding on the source and preservation history of Australian gas accumulations with direct implications on improving exploration success.

Throughout New Zealand, the Torlesse Supergroup forms an extensive Permian to Cretaceous accretionary wedge of rather monotonous, sandstone-dominated turbidites. In contrast to contemporaneous rocks in neighbouring terranes within the accretionary wedge, the turbidites have less intermediate-volcaniclastic compositions, and show more quartzose, continent-derived, plutonic provenances. Petrographic, geochemical, isotopic and detrital mineral age characteristics all indicate that they did not originate at the contemporary Gondwanaland margin in New Zealand, but rather, constitute a suspect terrane (Torlesse Terrane), having sediment sources elsewhere along the margin. This latter subject has been controversial, with sediment sources suggested in Antarctica, southern South America and northeast Australia, but detailed Torlesse detrital mineral (zircon and mica) age data and bulk rock Sr-isotope patterns can be best matched for the most part with Carboniferous, Permian and Triassic sources in the New England Orogen, and the remainder with Cambrian and Ordovician sources in its hinterland.

In this paper, we present a high resolution study focussed mainly on the Gorgon field and associated Rankin Trend gas fields, Carnarvon Basin, Australia (Figure 1). These gas fields are characterized by numerous stacked reservoirs with varying CO2 contents and provide a relevant natural laboratory for characterizing CO2 migration, dissolution and reaction by looking at chemical characteristics of the different reservoirs (Figure 2). The data we present reveal interesting trends for CO2 mol% and -13C both spatially and with each other as observed by Edwards et al. (2007). Our interpretation of the data suggests that mineral carbonation in certain fields can be significant and relatively rapid. The Gorgon and Rankin Trend fields natural gases may therefore be a unique natural laboratory, which give further insights into the rates and extent of carbonate mineral sequestration as applied to carbon storage operations.

Database containing analytical data and interpretations from the Geoscience Geoscience (GA) geochronology program. Includes some legacy methods and externally sourced data. A collection of analytical data to support geochronology data or ages used in other reporting and publications.

The Nolans Bore deposit, located in the Aileron Province of south-central Northern Territory, is a developing Australian rare earth element (REE) deposit. The deposit currently has a defined global resource of 30.2 Mt grading 2.8% rare earth oxides, 12.9% P2O5 and 200 ppm U3O8 (ASX:ARU 11/11/08). It consists of massive and brecciated fluorapatite veins that are up to 75-m-thick and hosted by ~1806 Ma granitic and metasedimentry units. Although initial drilling indicated that these veins dipped steeply to the NNW, more recent drilling has indicated a more complex 3D-vein configuration across the deposit. Even though apatite is the dominant mineral in the veins, the paragenesis is complex, with a massive zone of apatite-allanite-amphibole breccia, and numerous cross-cutting veins. The apatite hosts REE but it also typically contains abundant inclusions of other REE-bearing minerals, such as monazite and allanite along with other REE 'bearing phosphates, silicates and carbonates. Localised zones of higher grade REE mineralisation occur as intensely kaolinitised and clay altered rocks dominated by fine grained monazite and crandallite group minerals. A preliminary ~1240 Ma U-Pb age for apatite, which is interpreted as a minimum age, corresponds to a major period of global alkalic magmatism between 1300 and 1130 Ma. Low ?Nd and 87Sr/86Sr in the mineralisation are suggestive of EM-1 sources. The deposit is interpreted to be a carbonatite-related hydrothermal deposit. Fertilisation of the mantle to produce the EM-1 source may relate to subduction associated with older convergence along the southern margin of the North Australian Craton.

Australia as it exists today is a product of geological processes that have occurred over its 4.5 billion year history. Isotopic studies are one approach to understanding the history and evolution of the Australian continent. Isotope geochronology tells us about the timing of a wide range of geological processes like crystallisation, deformation and cooling of rocks. Isotope geochemistry informs on the precursor components from which the rocks formed, and can act as 'paleogeophysical' sensors to tell us more about the subsurface. The Isotopic Atlas of Australia brings together five of the most widely used isotopic systems in geology and delivers publicly available maps and datasets in a consistent format. This work is unlocking the collective value of decades of investment in data collection, and facilitating qualitative and quantitative comparison and integration with other datasets such as geophysical images. This talk will be an introduction to the world of isotopes as applied to understand geology, and an overview of the Isotopic Atlas recently produced as part of the Exploring for the Future Program.

New provenance data from Palaeoproterozoic and possible Archaean sedimentary units in the central eastern Gawler Craton forms part of a growing dataset suggesting that the Gawler Craton shares important basin formation and tectonic time lines with the adjacent Curnamona Province and the Isan Inlier in northern Australia. U-Pb dating of detrital zircons from the Eba Formation (previously mapped as Tarcoola Formation), yield exclusively Archaean ages (~2530-3300 Ma). This is consistent with whole rock Nd and zircon Hf isotopic data for the Eba Formation which have evolved compositions. Elsewhere in the eastern Gawler Craton, cover sequences historically considered to be Palaeoproterozoic in age also contain exclusively Neo and Meso Archaean aged detrital zircons (Reid et al, 2009 Econ. Geol.; Szpunar et al, 2007, SGTSG). The absence of Palaeoproterozoic detrital grains in several differently mapped sequences (including the Eba Formation) despite the proximity of voluminous Palaeoproterozoic rock units, suggests that the Eba Formation may be part of a Neo-Archaean or early Palaeoproterozoic cover sequence derived from erosion of a complex Archaean aged source region. The Labyrinth Formation unconformably overlies the Eba Quartzite, and contains rhyolitic units that constrain deposition to 1715 ± 9 Ma (Fanning et al., 2007; PIRSA Bulletin 55). This age is identical to the timing of deposition of the lower Willyama Supergroup in the adjacent Curnamona Province. Detrital zircon ages in the Labyrinth Formation range from NeoArchaean to Palaeoproterozoic, and are consistent with derivation from > 1715 Ma components of the Gawler Craton. Isotopic zircon Hf data and whole rock Nd data also suggest a source region with a mixed crustal evolution (-Nd -4.5 to -6), consistent with what is known about the Gawler Craton. Compared to the Lower Willyama Supergroup, the Labyrinth Formation has a source more obviously reconcilable with the Gawler Craton.