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  • The coverage of this dataset is over the Taree region . The C3 LAS data set contains point data in LAS 1.2 format sourced from a LiDAR ( Light Detection and Ranging ) from an ALS50 ( Airborne Laser Scanner ) sensor . The processed data has been manually edited to achieve LPI classification level 3 whereby the ground class contains minimal non-ground points such as vegetation , water , bridges , temporary features , jetties etc . Purpose: To provide fit-for-purpose elevation data for use in applications related to coastal vulnerability assessment, natural resource management ( especially water and forests) , transportation and urban planning . Additional lineage information: This data has an accuracy of 0.3m ( 95 confidence ) horizontal with a minimum point density of one laser pulse per square metre. For more information on the data's accuracy, refer to the lineage provided in the data history .

  • Integrating surface water and groundwater sampling with pore fluid analysis of cored sediments, combined with fuzzy-k means (FCM) cluster analysis, provides a novel, relatively simple but powerful tool to interpret groundwater processes. This methodology has been applied to a study of shallow (<120m) alluvial aquifers in the Darling River floodplain, Pore fluids were extracted from sediments from 100 sonic-cored bores, and together with surface and groundwater samples, provided a hydrochemical dataset with over 1600 samples and 25 analytes. The FCM cluster analysis used analytes that were present in at least 60% of samples and resulted in samples being classified into eight classes (or hydrochemical facies). Pore fluids and groundwaters with the greatest affinity to the surface water samples were easily identified. In this way, sites with significant active recharge, principally by river leakage, were mapped. Downhole plots of the pore fluid FCM classes provided additional insights into groundwater processes. Comparing the FCM classification of pore fluids within the target (semi)confined aquifer with those from the overlying clay aquitard and shallow aquifer allowed the assessment of vertical inter-aquifer leakage. The FCM cluster analysis also assigns indices to each sample as indicators of how well it relates to each of the eight classes. A simple recharge index was calculated from these FCM indices. This novel approach has provided invaluable new insights into groundwater processes and has assisted greatly with assessing groundwater resources and managed aquifer recharge options.

  • The under-explored deepwater Otway and Sorell basins lie offshore of southwestern Victoria and western Tasmania in water depths of 100-4,500 m. The basins developed during rifting and continental separation between Australia and Antarctica from the Cretaceous to Cenozoic and contain up to 10 km of sediments. Significant changes in basin architecture and depositional history from west to east reflect the transition from a divergent rifted continental margin to a transform continental margin. The basins are adjacent to hydrocarbon-producing areas of the Otway Basin, but despite good 2D seismic data coverage, they remain relatively untested and their prospectivity is poorly understood. The deepwater (>500 m) section of the Otway Basin has been tested by two wells, of which Somerset 1 recorded minor gas shows within the Upper Cretaceous section. Three wells have been drilled in the Sorell Basin, where minor oil and gas indications were recorded in Maastrichtian rocks near the base of Cape Sorell 1. Building on previous GA basin studies and using an integrated approach, new aeromagnetic data, open-file potential field, seismic and exploration well data have been used to develop new interpretations of basement structure and sedimentary basin architecture. Analysis of potential field data, integrated with interpretation of 2D seismic data, has shown that reactivated north-south Paleozoic structures, particularly the Avoca-Sorell Fault System, control the transition from extension through transtension to a dominantly strike-slip tectonic regime along this part of the southern margin. Depocentres to the west of this structure are large and deep in contrast to the narrow elongate depocentres to its east. Regional-scale mapping of key sequence stratigraphic surfaces across the basins has resulted in the identification of distinct basin phases. Three periods of upper crustal extension can be identified. In the north, one phase of extension in the Early Cretaceous and two in the Late Cretaceous can be mapped. However, to the south, the Late Cretaceous extensional phase extends into the Paleocene, reflecting the diachronous break-up history. Extension was followed by thermal subsidence, and during the Eocene-Oligocene the basin was affected by several periods of compression, resulting in inversion and uplift. The new seismic interpretation shows that depositional sequences hosting active petroleum systems in the producing areas of the Otway Basin are also likely to be present in the southern Otway and Sorell basins. Petroleum systems modelling suggests that if the equivalent petroleum systems elements are present, then they are mature for oil and gas generation, with generation and expulsion occurring mainly in the Late Cretaceous in the southern Otway and northern Sorell basins and during the Paleocene in the Strahan Sub-basin (southern Sorell Basin). The integration of sequence stratigraphic interpretation of seismic data, regional structural analysis and petroleum systems modelling has resulted in a clearer understanding of the tectonostratigraphic evolution of this complex basin system. The results of this study provide new insights into the geological controls on the development of the basins and their petroleum prospectivity.

  • A study of the consistency of gust wind speed records from two types of recording instruments has been undertaken. The study examined the Bureau of Meteorology's (BoM) wind speed records in order to establish the existence of bias between coincident records obtained by the old pressure-tube Dines anemometers and the records obtained by the new cup anemometers. This study was an important step towards assessing the quality and consistency of gust wind speed records that form the basis of the Australian Standards/NZ Standards for design of buildings for wind actions (AS/NZS 1170.2:2011 and AS 4055:2006). The Building Code of Australia (BCA) requires that buildings in Australia meet the specifications described in the two standards. BoM has been recording peak gust wind speed observations in the Australian region for over 70 years. The Australia/New Zealand Wind Actions Standard as well as the wind engineering community in general rely on these peak gust wind speed observations to determine wind loads on buildings and infrastructure. In the mid-1980s BoM commenced a program to replace the aging Dines anemometers with Synchrotac and Almos cup anemometers. During the anemometer replacement procedure, many localities had both types of anemometers recording extreme events. This allowed us to compare severe wind recordings of both instruments to assess the consistency of the recordings. The results show that the Dines anemometer measures higher gust wind speeds than the 3-cup anemometer when the same wind gust is considered. The bias varies with the wind speed and ranges from 5 to 17%. This poster presents the methodology and main outcomes from the assessment of coincident measurements of gust wind speed.

  • Broken Hill Managed Aquifer recharge Projects 3D models and Fly-through

  • Like many of the basins along Australia's eastern seaboard, there is currently only a limited understanding of the geothermal energy potential of the New South Wales extent of the Clarence-Moreton Basin. To date, no study has examined the existing geological information available to produce an estimate of subsurface temperatures throughout the region. Forward modelling of basin structure using its expected thermal properties is the process generally used in geothermal studies to estimate temperatures at depth in the Earth's crust. The process has seen increasing use in complex three-dimensional (3D) models, including in areas of sparse data. The overall uncertainties of 3D models, including the influence of the broad assumptions required to undertake them, are generally only poorly examined by their authors and sometimes completely ignored. New methods are presented in this study which will allow estimates and uncertainties to be addressed in a quantitative and justifiable way. Specifically, this study applies Monte Carlo Analysis to constrain uncertainties through random sampling of statistically congruent populations. Particular focus has been placed on the uncertainty in assigning thermal conductivity values to complex and spatially extensive geological formations using only limited data. As a case study these new methods are then applied to the New South Wales extent of the Clarence-Moreton Basin. The geological structure of the basin has been modelled using data from existing petroleum drill holes, surface mapping and information derived from previous studies. A range of possible lithological compositions was determined for each of the major geological layers through application of compositional data analysis. In turn, a range of possible thermal conductivity values was determined for the major lithology groups using rock samples held by the NSW Department of Primary Industries (DPI). These two populations of values were then randomly sampled to establish 120 different forward models, the results of which have been interpreted to present the best estimate of expected subsurface temperatures, and their uncertainties. These results suggest that the Clarence-Moreton Basin has a moderate geothermal energy potential within an economic drilling depth. This potential however, displays significant variability between different modelling runs, which is likely due to the limited data available for the region. While further work could improve these methods, it can be seen from this study that uncertainties can provide a means by which to add confidence to results, rather than undermine it.

  • Geoscience Australia has recently completed a survey searching for evidence of natural hydrocarbon seepage in the offshore northern Perth Basin, off Western Australia. The survey formed part of a regional assessment of the basin's petroleum prospectivity in support of ~17,000 sq km of frontier exploration acreage release in the region in 2011. Multibeam bathymetry, sub-bottom profiler, sidescan sonar and echosounder data were acquired to map seafloor and water column features and characterise the shallow sub-surface sediments. A remotely operated vehicle (ROV) was used to observe and record evidence of seepage on the seafloor. 71 sediment grabs and 28 gravity cores were collected and are currently being analysed for headspace gas, high molecular weight biomarkers and infaunal content. Survey data identified an area of high 'seepage' potential in the northernmost part of the study area. Recent fault reactivation and amplitude anomalies in the shallow strata correlate with raised, high-backscatter regions and pockmarks on the seafloor. A series of hydroacoustic flares identified with the sidescan sonar may represent gas bubbles rising through the water column. The ROV underwater video footage identified a dark-coloured fluid in 500 metres water depth proximal to the sidescan flares which may be oil that naturally seeped from the seafloor. The integration of the datasets acquired during the marine survey is indicative of natural oil seepage and provides additional support for the presence of an active petroleum system on this part of the continental margin.

  • Modern geodetic techniques, especially the Global Positioning System (GPS) have allowed the accurate determination of the Earth's surface deformation of Glacial Isostatic Adjustment (GIA) associated with the ongoing stress release of the viscoelastic mantle after removal of the Late Pleistocene ice-sheets. We present an inversion analysis of the GPS derived deformation in North America to determine the effective lithosphere thickness and mantle viscosity, and examine whether the GPS observations can be fit with the ice-sheets and earth models, which were constructed and inferred mainly from geomorphologic/geological and relative sea level (RSL) data. The inversion computation is conducted for horizontal and vertical deformation, separately and jointly with two ice-sheet models (ANU-ICE and ICE-5G) developed independently by the Australian National University (ANU) and University of Toronto. The results from a simple three-layer earth model give a lithosphere thickness of 100~130km, an upper-mantle viscosity of 7~10 × 1020 Pa s, and a lower-mantle viscosity of 1.5~2.8 × 1021 Pa s. More sophisticated models such as introducing a transition zone of 400-670km failed to improve model fit, and the related parameters are mostly consistent with those of three-layer models. Further tests show that models of a thin-layer (30~40km) of large viscosity (~1022 Pa s) did not provide a better fit to the data. Ice scaling tests show that vertical deformation is more sensitive to local ice configuration. An increase of ice thickness by ~40% in Alberta and a reduction by ~50% between Saskatchewan and West Ontario are required to fit both horizontal and vertical deformation observed in Southwest Canada, whereas a reduction of ice thickness by ~25% for ANU-ICE produced an improved fit to both horizontal and vertical deformation in Quebec. Results from inversion analysis of two sub-datasets in Southwest and Southeast Canada revealed a 40% difference in the lower-mantle viscosity, which indicates that the lower-mantle in Southeast Canada could be relatively stronger. There is a discrepancy in the upper-mantle viscosity estimate between horizontal and vertical deformation: a low value (3~5 × 1020 Pa s) required by vertical deformation, and a high value (~9 × 1020 Pa s) favoured by horizontal deformation, which is due possibly to under-represented vertical deformation in the region as well as uncertainties in local ice topography. Overall, the earth model estimated from inversion analysis of GPS data in North America is consistent with the early inference from forward analyses of RSL data (e.g. Tushingham & Peltier, 1992): the lower-mantle viscosity is a factor of 1.5~2.0 larger than upper-mantle viscosity of ~1021 Pa s, reflecting that the main features of the earlier constructed North American ice-sheets (e.g. ICE-3G) are unchanged after two decade refinements.