Here we report on the application of a new CO2 quantification and localization technique, called atmospheric tomography. The results of the study indicate that, through careful data processing, measurements from the comparatively inexpensive but lower accuracy and lower precision CO2 sensor array can provide useful data. Results from the application of the tomography technique will be presented and limitations of the technique discussed. From the 9th International Carbon Dioxide Conference, Beijing, China

Australia has been making major progress towards early deployment of carbon capture and storage from natural gas processing and power generation sources. This paper will review, from the perspective of a government agency, the current state of various Australian initiatives and the advances in technical knowledge up until the 2010 GHGT conference. In November 2008, the Offshore Petroleum and Greenhouse Gas Storage Bill 2006 was passed by the Australian Parliament and established a legal framework to allow interested parties to explore for and evaluate storage potential in offshore sedimentary basins that lie in Australian Commonwealth waters. As a result of this Act, Australia became the first country in the world, in March 2009, to open exploration acreage for storage of greenhouse gases under a system that closely mirrors the well-established Offshore Petroleum Acreage Release. The ten offshore areas offered for geological storage assessment are significantly larger than their offshore petroleum counterparts to account for, and fully contain, the expected migration pathways of the injected GHG substances. The co-incidence of the 2009 Global Financial Crisis may have reduced the number of prospective CCS projects that were reported to be in the 'pipe-line' and the paper examines the implications of this apparent outcome. The Carbon Storage Taskforce has brought together both Australian governments technical experts to build a detailed assessment of the perceived storage potential of Australia's sedimentary basins. This evaluation has been based on existing data, both on and offshore. A pre-competitive exploration programme has also been compiled to address the identified data gaps and to acquire, with state funding, critical geological data which will be made freely available to encourage industrial participation in the search for commercial storage sites.

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.

This abstract is for an invited presentation at the CRC LEME Advances in Regolith Symposia in Canberra November 2003

We report on an assessment of severe wind hazard across the Australian continent, and severe wind risk (quantified in annualised losses due to severe wind damage) in built up areas, based on innovative modelling techniques and application of the National Exposure Information System (NEXIS). A combination of tropical cyclone, synoptic and thunderstorm wind hazard estimates is used to provide a revised estimate of the severe wind hazard across Australia. The hazard modelling techniques developed in this assessment utilise both 'current-climate' and also simulations forced by IPCC SRES climate change scenarios, which have been employed to determine how the wind hazard will be influenced by climate change. We have also undertaken a national assessment of localised wind speed modifiers including topography, terrain and built environment. It is important to account for these effects in assessment of risk as it is the local wind speed that causes damage to structures. The effects of the wind speed modifiers are incorporated through a statistical modification of the regional wind speed. The results from this current climate hazard assessment are compared with the hazard based on the existing understanding as specified in the Australian/New Zealand Wind Loading Standard (AS/NZS 1170.2, 2002). Regions are mapped where the design wind speed depicted in AS/NZS 1170.2 is significantly lower than 'new' hazard analysis. These are regions requiring more immediate attention regarding the development of adaptation options including consideration by the wind loading standards committee for detailed study in the context of the minimum design standards in the current building code regulations. Considering future climate scenarios, the Tasmanian region is used to illustrate where the wind loading standard becomes inadequate, and where retrofitting is indicated as a viable adaptation option at a specified future time. The cost/benefit analysis techniques used will be demonstrated.

The worldwide attention has focussed on large-scale carbon capture and storage (CCS) projects to mitigate global climate change. The Caswell Fan in the Browse Basin, Australian North West Shelf, has been identified as a possible reservoir unit suitable for large-scale CO2 storage. It was formed as an unconfined basin floor fan during the Late Campanian. This study aimed to assess the CO2 storage potential of the Caswell Fan through an integrated reservoir modelling study. Seismic interpretation and velocity modelling results have been incorporated into the construction of a 3D grid system. The lithofacies and petrophysical property modelling were then carried out based on the well log evaluation and sedimentary analysis. Due to the limited well data, the seismic amplitude was integrated as the secondary data to model the spatial distributions of reservoir porosity and permeability by employing Kriging interpolation with locally varying mean. Geological modelling of Caswell reservoir showed that the average reservoir porosity is 18.3 percent and the maximum true thickness of Caswell Fan is 260.5 m. Using US DOE methodology with a storage coefficient of 2.70 percent, the study has estimated storage potential of the Caswell reservoir to be approximately 300 million tonnes. Dynamic reservoir simulation has been undertaken to evaluate the practical CO2 storage capacity of the Caswell Fan. On the basis of compositional dynamic simulation, the capacity is estimated as 170 million tonnes with six vertical injection wells, and the practical storage coefficient of the Caswell Fan is approximately 1.56 percent.

The continental margin of East Antarctica between Dronning Maud and George V Lands shows no evidence of widespread breakup-related volcanism, other than adjacent to the southern Kerguelen Plateau, and it therefore constitutes one of the largest tracts of non-volcanic rifted margin on the planet. The integrated interpretation of deep-seismic, velocity and potential field data acquired in 2001/02 shows that there are first-order structural variations between the two main sectors of this margin. In the west, the Enderby Land margin formed by the separation of Greater India from Antarctica, commencing in the Valanginian (ca. 131 Ma). Seawards of a major basement fault zone underlying the continental slope, deep-seated continental crust is characterised by high-angle brittle faulting; seismic data provide little information on the style of the deeper crustal deformation. The other prominent structural features of this margin are a sharp continent-ocean boundary (COB), characterised by an oceanwards step-up in the basement level of up to 1 km, and an earliest phase of ocean crust that is distinctive for its rich internal reflection fabric and strong Moho reflection. Potential field modelling indicates that the gross margin structure is relatively simple, and that both the continental and oceanic crusts have behaved as a semi-rigid plate that has been depressed landwards by the thick (4-9 km) post-rift sediment loading. In the east, the Wilkes Land margin formed during the separation of Australia and Antarctica, commencing with very slow seafloor spreading in the early Campanian (ca. 83 Ma). This margin is dominated by the broad and highly structured transition from the attenuated continental crust inboard on the margin, to the mechanically extended and largely amagmatic oceanic crust that formed during the initial seafloor spreading. From inboard to outboard across this zone, the structuring is characterised by: ? plastic and brittle deformation of the lower continental crust and upper mantle; ? a ridge of interpreted serpentinised peridotite that can be traced along strike on the margin for a distance of at least 800 km; ? a sedimentary basin outboard of the ridge that appears to be underlain by fragments of crystalline continental crust; and ? a COB between mechanically extended continental and oceanic crust that is complex and not readily delineated. The structures of the Wilkes Land margin are very similar to those on the conjugate southern Australian margin, indicating that at least the final stage of rifting between Antarctica and Australia was inherently symmetrical. The wide differences between the structural styles documented on the Enderby and Wilkes Land margins indicate that tectonic processes forming non-volcanic rifted margins may differ significantly depending on a range of factors that may include pre-existing heterogeneities in the continental crust, the thermal regime and the pre-breakup intra-plate stress regime.

Continuously cored ODP Leg 189 sites document the marine sequences deposited before, during and after the Tasmanian (Australian-Antarctic) Gateway opened (~33.5 Ma) and deepened. The sites are all on continental crust: one west of Tasmania, three on South Tasman Rise (STR) and one on East Tasman Plateau (ETP). The Tasmanian `land bridge? linked Australia and Antarctica and incorporated parts of Tasmania and STR; one site lay in the gradually widening but restricted Australo-Antarctic Gulf (AAG) in the Indian Ocean, and the others in the more open proto-Pacific Ocean. The main four sites vary in sub-seafloor depth from 776 to 959 m, and their oldest sequence from lowest Upper Eocene (AAG) to Maastrichtian (ETP). The sites are broadly similar, with variations depending on tectono-sedimentary setting. Depositional rates seldom exceeded 4 cm/ky. Until the Oligocene, the region was near the Antarctic margin in very high palaeolatitudes, and dinocyst, diatom and magnetostratigraphic data provide most dating and marine environmental information. From the Late Cretaceous through Late Paleocene (95-55 Ma) left-lateral strike-slip motion moved the Tasmanian region northwest past Antarctica, and Tasman Basin rifting and seafloor spreading occurred in the east. Deltaic sequences filled depocentres with dark, restricted, paralic and marine mudstones (drilled on ETP, STR). At the Paleocene/Eocene boundary (55 Ma) Australia-Antarctic motion changed to north-south along the Tasman Fracture Zone west of STR, and Tasman Basin spreading ceased. South of eastern STR an oceanic basin opened. Fast spreading, beginning in the Middle Eocene, carried this region northward (~43 Ma). In the Early and Middle Eocene, deposition continued of dark, largely deltaic, and broadly similar shallow marine mudstones (thinnest on ETP). Proto-Pacific mudstones become more open marine with time, but AAG mudstones remained restricted. In the Late Eocene (37-33.5 Ma) the continental margins sagged, the water deepened, and some currents may have flowed through shallow seaways. Sedimentation rates declined as winnowing increased and hiatuses formed. On the AAG margin restricted shallow marine mudstone and sandstone were deposited. In the proto-Pacific, as the water deepened in the latest Eocene, marine mudstone gave way to winnowed marine glauconitic siltstone and sandstone. Rapid subsidence followed the final separation of STR and Antarctica. In the proto-Pacific, strong currents swept the shelves and opening straits, and an Early Oligocene hiatus was overlain by Oligocene open marine bathyal carbonates. The AAG margin was now less restricted, but calcareous mudstones had only gradual carbonate increases through into the lower Miocene. From the Oligocene on, calcareous nannofossils, planktonic foraminifers and magnetostratigraphic data provide most dating and marine environmental information. The Neogene sequences, which consist of bathyal chalk and oozes, with limited disconformities in parts of the Miocene, have proved ideal for detailed palaeo-oceanographic/climatic isotope studies - rare in the Southern Ocean.

The Tanami region is one of Australia?s premier Proterozoic gold provinces, having already produced ~150 t of gold, and still has high exploration potential. This region contains more than 60 gold occurrences including the Dead Bullock Soak, Groundrush and The Granites gold mines as well as several significant gold prospects (Coyote, Crusade and Kookaburra). The Callie deposit (>5 Moz Au total resource) located in the Dead Bullock Soak goldfield is currently the largest mine in this region. Previous studies of the mineral systems associated with the gold deposits in the Tanami region indicate that they formed over a range of depths and were hosted in both greenstone and sedimentary units. Fluid inclusion studies have shown that the ore-bearing fluids were generally of low to moderate salinity with varying amounts of CO2?N2?CH4. Trapping temperatures ranged from 220 to 430 ?C. In order to determine the extent of these gold mineral systems, we have investigated the chemistry of the fluids in regional quartz veins that outcrop in both the Tanami, Birrindudu and northern Arunta. 40Ar/39Ar dating of veins containing mica was also carried out to determine the timing of the veins with respect to the mineralisation in the Tanami region. Epithermal veins outcrop along the southern margin of the Wiso Basin, the northern Arunta, the western Tanami and in the Birrindudu region. Two populations of fluid inclusions were observed in the epithermal veins: a low salinity fluid (<1 wt. % NaCl eq), and a high salinity fluid (>18 wt. % NaCl eq). No gases were detected in either type of fluid inclusion and both homogenised over the range from 120 to 180 ?C. Regional E-W trending mesothermal quartz veins outcrop in the southern Tanami region and a distinctive zone of ENE trending quartz veins outcrop in the northern Arunta whereas both NW trending and ENE trending veins occur in the Birrindudu region. Two populations of fluid inclusions were also observed in these mesothermal quartz veins. The first contained low salinity fluids with CO2>CH4?(N2?graphite). These inclusions homogenised between 320 and 360 ?C. The second population contained high salinity fluids with no detectable gases and they homogenised between 120 and 230 ?C. 40Ar/39Ar dating of quartz veins containing mica showed a distinct difference in the age of the veins in the Tanami and northern Arunta. Mesothermal veins in the Tanami region had ages ranging from 1700 to 1741 Ma while quartz veins in the northern Arunta gave ages ranging from 1432 to 1518 Ma. This suggests that these vein sets formed from two separate fluid flow events.

Tropical cyclones, thunderstorms and sub-tropical storms can generate extreme winds that can cause significant economic loss. Severe wind is one of the major natural hazards in Australia. The Geoscience Australia's Risk and Impact Analysis Group (RIAG) is developing mathematical models to study a number of natural hazards including wind hazard. In this study, RIAG's wind hazard model for non-cyclonic regions of Australia (Region A in the Australian-New Zealand Wind Loading Standard; AS/NZS 1170.2(2010)) for both current and a range of projected future climate are discussed. The methodology involves a combination of 3 models: - A Statistical Model (ie. a model based on observed data) to quantify wind hazard using extreme value distributions. - A technique to extract and process wind speeds from a high-resolution regional climate model (RCM) which produces gridded hourly 'maximum time-step mean' wind speed and direction fields, and a - Monte Carlo method to generate gust wind speeds from the RCM mean winds. Gust wind speeds are generated by a numerical convolution of the mean wind speed distribution and a regional 'observed' gust factor. Wind hazard at a particular location is affected by the corresponding wind direction. In the last part of this paper a methodology to calculate wind direction multipliers over a region is presented. These multipliers are used to assess the actual wind hazard at the given location. To illustrate the methodology involved with the calculation of severe wind hazard, including the effect of wind direction, analysis over the Australian state of Tasmania will be presented (current and future climate).