As part of the Australian Government's National CO2 Infrastructure Plan (NCIP), Geoscience Australia undertook a CO2 storage assessment of the Vlaming Sub-basin. The Vlaming Sub-basin a Mesozoic depocentre within the offshore southern Perth Basin located about 30 km west of Perth, Western Australia. The main depocentres formed during the Middle Jurassic to Early Cretaceous extension. The post-rift succession comprises up to 1500 m of a complex fluvio-deltaic, shelfal and submarine fan system. Close proximity of the Vlaming Sub-basin to industrial sources of CO2 emissions in the Perth area drives the search for storage solutions. The Early Cretaceous Gage Sandstone was previously identified as a suitable reservoir for the long term geological storage of CO2 with the South Perth Shale acting as a regional seal. The Gage reservoir has porosities of 23-30% and permeabilities of 200-1800 mD. The study provides a more detailed characterisation of the post Valanginian Break-up reservoir - seal pair by conducting a sequence stratigraphic and palaeogeographic assessment of the SP Supersequence. It is based on an integrated sequence stratigraphic analysis of 19 wells and 10, 000 line kilometres of 2D reflection seismic data, and the assessment of new and revised biostratigraphic data, digital well logs and lithological interpretations of cuttings and core samples. Palaeogeographies were reconstructed by mapping higher-order prograding packages and establishing changes in sea level and sediment supply to portray the development of the delta system. The SP Supersequence incorporates two major deltaic systems operating from the north and south of the sub-basin which were deposited in a restricted marine environment. Prograding clinoforms are clearly imaged on regional 2D seismic lines. The deltaic succession incorporates submarine fan, pro-delta, delta-front to shelfal, deltaic shallow marine and fluvio-deltaic sediments. These were identified using seismic stratigraphic techniques and confirmed with well ties where available. The break of toe slope was particularly important in delineating the transition between silty slope sediments and fine-grained pro-delta shales which provide the seal for the Gage submarine fan complex. As the primary reservoir target, the Gage lowstand fan was investigated further by conducting seismic faces mapping to characterise seismic reflection continuity and amplitude variations. The suitability of this method was confirmed by obtaining comparable results based on the analysis of relative acoustic impedance of the seismic data. The Gage reservoir forms part of a sand-rich submarine fan system and was sub-divided into three units. It ranges from canyon confined inner fan deposits to middle fan deposits on a basin plain and slump deposits adjacent to the palaeotopographic highs. Directions of sediment supply are complex. Initially, the major sediment contributions are from a northern and southern canyon adjacent to the Badaminna Fault Zone. These coalesce in the inner middle fan and move westward onto the plain producing the outer middle fan. As time progresses sediment supply from the east becomes more significant. Although much of the submarine fan complex is not penetrated by wells, the inner fan is interpreted to contain stacked channelized high energy turbidity currents and debris flows that would provide the most suitable reservoir target due to good vertical and lateral sand connectivity. The middle outer fan deposits are predicted to contain finer-grained material hence would have poorer lateral and vertical communication.

Superseded by 78944

The Clarence-Moreton and the Surat basins in Queensland and northern New South Wales contain the coal-bearing sedimentary sequences of the Jurassic Walloon Coal Measures, composed of up to approximately 600 m of mudstone, siltstone, sandstone and coal. In recent years, the intensification of exploration for coal seam gas (CSG) resources within both basins has led to concerns that the depressurisation associated with future resource development may cause adverse impacts on water resources in adjacent aquifers. In order to identify the most suitable tracers to study groundwater recharge and flow patterns within the Walloon Coal Measures and their degree of connectivity with over- or underlying formations, samples were collected from the Walloon Coal Measures and adjacent aquifers in the northern Clarence-Moreton Basin and eastern Surat Basin, and analysed for a wide range of hydrochemical and isotopic parameters. Parameters that were analysed include major ion chemistry, -13C-DIC, -18O, 87Sr/86Sr, Rare Earth Elements (REE), 14C, -2H and -13C of CH4 as well as concentrations of dissolved gases (including methane). Dissolved methane concentrations range from below the reporting limit (10 µg/L) to approximately 50 mg/L in groundwaters of the Walloon Coal Measures. However, the high degree of spatial variability of methane concentrations highlights the general complexity of recharge and groundwater flow processes, especially in the Laidley Sub-Basin of the Clarence-Moreton Basin, where numerous volcanic cones penetrate the Walloon Coal Measures and may form pathways for preferential recharge to the Walloon Coal Measures. Interestingly, dissolved methane was also measured in other sedimentary bedrock units and in alluvial aquifers in areas where no previous CSG exploration or development has occurred, highlighting the natural presence of methane in different aquifers. Radiocarbon ages of Walloon Coal Measure groundwaters are also highly variable, ranging from approximately 2000 yrs BP to >40000 yrs BP. While groundwaters sampled in close proximity to the east and west of the Great Dividing Range are mostly young, suggesting that recharge to the Walloon Coal Measures through the basalts of the Great Dividing Range occurs here, there are otherwise no clearly discernable spatial patterns and no strong correlations with depth or distance along inferred flow paths in the Clarence-Moreton Basin. In contrast to this strong spatial variability of methane concentrations and groundwater ages, REE and 87Sr/86Sr isotope ratios of Walloon Coal Measures groundwaters appear to be very uniform and clearly distinct from groundwaters contained in other bedrock units. This difference is attributed to the different source material of the Walloon Coal Measures (mostly basalts in comparison to other bedrock units which are mostly composed of mineralogical more variable Paleozoic basement rocks of the New England Orogen). This study suggests that REE and 87Sr/86Sr ratios may be a suitable tracer to study hydraulic connectivity of the Walloon Coal Measures with over- or underlying aquifers. In addition, this study also highlights the need to conduct detailed water chemistry and isotope baseline studies prior to the development of coal seam gas resources in order to differentiate between natural background values of methane and potential impacts of coal seam gas development.

Unlike land based environments, relatively little is known about what the seafloor around Australia looks like or has living on it. Geoscience Australia undertakes a range of marine surveys to improve the understanding and the management of Australia's marine environments. One component of the research involves the use a towed video system to directly observe coastal and deep sea environments and identify what habitats occur there and the organisms that live there. In some regions these surveys build on existing knowledge, but in many areas, particularly in deep offshore sites, these devices provide the first images of the seafloor. This data package includes towed video and still images acquired on GA surveys from 2007 onwards. Between 2007 and 2013, this included 21 marine surveys (including Antarctic waters). Using a winch on the ship, the video system is lowered to 1-2 metres above the seafloor and then towed along at 1-2 knots. This speed and altitude allows the video camera to record sharp images of the seafloor while covering distances of up to 1-2 km. Video footage is sent up a cable to the ship so it can be viewed in real time. The hours of footage collected on the seafloor provide a wealth of information about the geological features, habitats and life forms occurring throughout Australia's marine jurisdiction.

As part of the controlled release experiments at the Ginninderra test site, geophysical surveys have been acquired using electromagnetic techniques at a range of frequencies. The primary objective was to assess whether these could provide insight into the soil structure at the site, give guidance as to where to monitor for leakage, and provide additional information that may explain the observed sub-surface and surface CO2 migration behavior. A secondary objective was to assess whether CO2 leaks could be located based on secondary impacts such as drying of the soil profile. Ground penetrating radar surveys were taken during the second release experiment (October - December 2012). Different frequency shielded antennas were trialled in order to optimize the signal. Two surveys were conducted: one baseline survey prior to CO2 release and another during the release experiment. The GPR results show a reduction in range and clear reflections to the west indicating that clay was present. To the east we see clearer reflections from sand layers and the water table. These observations corresponded with larger scale sub-surface soil features determined from EM31 and EM38 electromagnetic surveys. Application of these geophysical surveys for CO2 leak detection and monitoring design are discussed. Paper for CO2CRC Research Symposium 2013

The Protocol on Environmental Protection to the Antarctic Treaty (the 'Madrid Protocol') includes provisions to protect areas of biological, scientific, historic, aesthetic or wilderness value. While these provisions have been mostly utilised to protect sites of biological or cultural significance, sites of geological or geomorphological significance may also be considered. To date, only two sites within East Antarctica (Marine Plain, Vestfold Hills and Mount Harding, Grove Mountains), have been declared as Antarctic Specially Protected Areas (ASPA) in recognition of their unique geological or geomorphological significance. Recently, however, Stornes, a peninsula in the Larsemann Hills (Prydz Bay) has been identified as a candidate due to the abundance and diversity of extremely rare granulite-facies borosilicate and phosphate minerals found there. The need for proactive intervention, protection and management of sites of intrinsic geoscientific value is becoming increasingly important. This recent example highlights the growing awareness of the intrinsic scientific value of Antarctic geological features within the AAT, including rare mineral or fossil localities. This awareness is identified within the current Australian Antarctic Science Strategic Plan and emphasises that geosciences can actively contribute to and influence the development of management plans and actively support Australia's commitments to Annex V of the Madrid Protocol. Wider recognition of the geological values achieved by invoking the provisions for area management, including creating the need to obtain the permission of a national authority to enter the area, should also mitigate casual souveniring and accidental or deliberate damage caused by ill-advised construction or other human activity.

The potential for using a single high precision atmospheric station for detecting CO2 leaks has been investigated using a variety of statistical approaches. Geoscience Australia and CSIRO Marine and Atmospheric Research installed an atmospheric monitoring station, Arcturus, in the Bowen Basin, Australia, in 2010 and have collected over 3 years' worth of atmospheric concentration measurements. The facility is designed as a prototype remote baseline monitoring station that could be deployed in areas targeted for commercial scale geological storage of carbon dioxide. Two Picarro gas analysers are deployed in the station to continuously monitor CO2, CH4 and CO2 isotopes. An automated weather station and an eddy covariance flux tower have also been installed at the site. Atmospheric CO2 perturbations, from simulated leaks, have been modelled to determine the minimum statistically significant emissions that can be detected above background concentrations at Arcturus. CO2 leakage was simulated from January to December (2011) using a 3D-coupled prognostic meteorological and pollutant dispersion model (TAPM). Simulations were conducted for various locations, emission rates and distances (1-10 km) from the station. The simulated leaks were simulated using an area source (100 m x 100 m) and a point source located in the optimum wind direction (SSE), which showed the largest perturbation. To better understand the observed CO2 signal, a statistical model combining both a regression and time series model was constructed. The regression model is a time dependent generalised additive model relating the CO2 to other observed atmospheric variables (e.g. wind speed, temperature, humidity). It accounts for seasonal trends through the inclusion of dummy variables. The time series model is based on a seasonal auto-regressive integrated moving average (ARIMA) model, but with the additional complexity of allowing auto-regressive relationships to depend on the time of day. A non-parametric goodness of fit approach using the Kolmogorov-Smirnoff (KS) test was then used to test whether simulated perturbations can be detected against the modelled expected value of the background for certain hours of the day and for particular seasons. The developed regression model allows us to pre-whiten the CO2 time series. Pre-whitening reduces both the variance and skew of the marginal distribution of the signal. This improves the power of the Kolmogorov-Smirnoff (KS) test when attempting to detect simulated perturbations against the background signal. The KS test calculates the probability that the modelled leak perturbation could be caused by natural variation in the background. For hours between 10am and 2pm in the winter of 2011, minimum detectable leaks located 1km from the measurement station improve from 44 to 22 tpd for an area source and 33 to 14 tpd for a point source at a p-value of 0.05. These are very large leaks located only 1 km from the station. Additionally, this approach results in a high false alarm rate of 56%. An alternative p-value could be chosen to reduce the false alarm rate but the overall conclusion is the same. A long term, single measurement station monitoring program that is unconstrained by prior information on possible leaks, and based on detection of perturbations of CO2 alone due to leakage above a (noisy) background signal, is likely to take one or more years to detect leaks of the order of 10kt p.a.

ARR is a series of national guidelines and datasets fundamental to flood estimation. The work is being completed by Engineers Australia and funded by the Australian Government through the National Flood Risk Information Project at Geoscience Australia. This flyer is for promoting the revision of ARR at the Hydrology & Water Resources Symposium (HWRS 2015) in Hobart in December 2015.

A major concern for regulators and the public with geological storage of CO2 is the potential for the migration of CO2 via a leaky fault or well into potable groundwater supplies. Given sufficient CO2, an immediate effect on groundwater would be a decrease in pH which could lead to accelerated weathering, an increase in alkalinity, release of major and minor ions and heavy metals (particularly Pd, Ni and Cr) as well as CO2 mobilisation of trace organic contaminants. These scenarios potentially occur in a high CO2 leakage event, therefore detection of a small leak, although barely perceptible, could provide an important early warning for a subsequent and more substantial impact. Different approaches are required for the detection and quantification of these low level leaks and are the subject of this paper. A 3 year groundwater survey was recently completed in the Surat Basin, which provided comprehensive water and isotopic analysis of groundwaters together with their exsolved gases. The gases were analysed for composition, -13CCO2, -13CCH4 and -2HCH4. Methane is prevalent in the major Surat Basin aquifers (e.g. Mooga, Gubberamunda and Hutton sandstones) and is invariably associated with a bacterial (methanogenic) carbonate reduction source, evident from its isotopic signature ('13CCH4 ~ -70', '2HCH4 ~ -220'). In addition to methane and low levels of CO2, trace ethane is common. Two neighbouring wells, however, were quite different to the other 85 wells surveyed. Their exsolved gases contained comparatively high ethane, but also C1-C6 hydrocarbons in addition to methane. Methane isotope systematics were significantly different from other groundwater wells completed in the same formation. The -13C of the CO2 was similar to the surrounding groundwater wells, but the relative proportion of CO2 in the gas was significantly higher. Combined, these characteristics are consistent with hydrocarbon biodegradation. There was little difference in the groundwater chemistry for these wells compared to the regional baseline. The study provides a useful analogue study for detection, at various scales, of a leaky well associated with a geological storage site. Compositional and isotopic analysis of exsolved gases from groundwater samples could be used to demonstrate non-equilibrium conditions and intrusion of exogenic CO2. Abstract for the 2013 International Association of Hydrologist Congress, Perth

CO2CRC Symposium 2013: Oral presentation as part of a tag-team Ginninderra presentation As part of the controlled release experiments at the Ginninderra test site, a total of 14 soil flux surveys were conducted; 12 during the first experiment (March 2012 - June 2012), and 2 during the second experiment (October - December 2012). The aim was to determine what proportion of the known CO2 that was released could be measured using the soil flux method as a quantification tool. The results of this study enabled us to use the soil flux measurements as a proxy for other CO2 quantification methods and to gain an understanding of how the CO2 migrated within the sub-surface. For experiment one; baseline surveys were conducted pre-release, followed by surveys several times a week during the first stages of the release. The CO2 'breakthrough' was detected only 1 day after the release began. Surveys were then conducted weekly to monitor the flux rate over time. The soil CO2 flux gradually increased in magnitude until almost reaching the expected release rate (128 kg/day measured while the release rate was 144 kg/day) after approximately 4 weeks, and then receded quickly once the controlled release was stopped. Soil gas wells confirm that there is significant lateral migration of the CO2 in the sub-surface, suggesting that there was a degree of accumulation of CO2 in the sub-surface during the experiment.