Browsing by Author "Feitz, A"

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    Hydrochemical and isotopic fingerprinting of the Walloon coal measures and adjacant aquifiers in the Clarence-Moreton and Eastern Basins in Southeast Queensland
    (Geological Society of Australia, 2014-07-07) Raiber, M; Cendón, DI; Feitz, A; Sundaram, B; Suckow, A
    The Clarence-Moreton Basin in New South Wales and Queensland is one of six nationwide priority regions where the potential impacts of future coal seam gas extractions and coal mining on water-dependent assets are being assessed through a national programme of Bioregional Assessments. The Clarence-Moreton Basin is an elongated intracratonic sag basin that contains sedimentary sequences of Middle and Late Triassic to Lower Cretaceous age with a combined thickness of up to approximately 3500 to 4000 m. Overlying the basin sedimentary sequences within the Clarence-Moreton bioregion (the eastwards draining part of the basin) are five major catchment systems (Lockyer Valley, Bremer/Warrill, Logan/Albert in Queensland, and the Richmond and Clarence river catchments in NSW), which host important alluvial groundwater and surface water resources that are intensively used for irrigation. In addition, these catchments host significant assets such as groundwater-dependant ecosystems (e.g. springs and wetlands). In order to predict the potential impacts of depressurisation associated with coal seam gas extraction from the Walloon Coal Measures (major target of CSG exploration in the Clarence-Moreton Basin), an accurate understanding of the links between different components of the hydrological system is essential. Prior to the development of numerical models, it is critical to describe potential connectivity pathways between deep and shallow aquifers, as well as interaction between groundwater and surface water. In order to assist with the development of reliable conceptual models that describe these interactions and constitute a road map to bioregional assessments, we have constructed a 3D geological model from elevation (DEM), stratigraphic, seismic and lithological data using GoCAD (Paradigm) 3D geological modelling software. The 3D geological model represents the major alluvial, sedimentary and volcanic aquifers and aquitards of the Clarence-Moreton bioregion. It helps to develop a more realistic understanding of the aquifer system behaviour, particularly if integrated with complementary data sources such as water level or hydrochemical data, and it will provide the geometric framework for the groundwater numerical model. The 3D geological model highlights the structural complexity of the Clarence-Moreton Basin, with significant vertical displacements of major basin units of several hundred meters registered along major regional fault systems, and abutments of stratigraphic units against basement ridges or pinching out of units observed in different parts of the basin. These observed structural features and the geometric characteristics of aquifers/aquitards can have a significant influence on potential connectivity pathways. For example, the thinning of the Gatton Sandstone against the underlying Woogaroo Subgroup at the basin margin in the Lockyer Valley results in upwards seepage of groundwater from the Gatton Sandstone into the alluvial aquifer, and this upwards discharge probably also feeds wetlands located along the northern margin of the Gatton Sandstone.
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    Multi-tracer approach to investigate groundwater recharge and aquifer connectivity in the Clarence-Moreton and eastern Surat basins in southeast Queensland
    (National Centre for Groundwater Research And Training, 2015-11-03) Raiber, M; Feitz, A; Cendón, DI; Suckow, A
    The Walloon Coal Measures (WCM) in the Clarence-Moreton and the Surat basins in QLD and northern NSW contain up to approximately 600 m of mudstone, siltstone, sandstone and coal. Wide-spread exploration for coal seam gas (CSG) within both basins has led to concerns that the depressurisation associated with the resource development may impact on water resources in adjacent aquifers. In order to predict potential impacts, a detailed understanding of sedimentary basins hydrodynamics that integrates geology, hydrochemistry and environmental tracers is important. In this study, we show how different hydrochemical parameters and isotopic tracers (i.e. major ion chemistry, dissolved gas concentrations, δ2H and δ13C of CH4, δ13C-DIC, δ18O, δ2H, 87Sr/86Sr, 3H, 14C and 36Cl) can help to improve the knowledge on groundwater recharge and flow patterns within the coal-bearing strata and their connectivity with over- or underlying formations. Dissolved methane concentrations in groundwaters of the WCM in the Clarence-Moreton Basin range from below the reporting limit (10 μg/L) to approximately 50 mg/L, and samples collected from nested bore sites show that there is also a high degree of vertical variability within the aquifer. Other parameters such as 3H, δ13C & 14C in DIC collected along assumed flow paths are also highly variable, which indicates local groundwater flow cells rather than regional flow. In contrast, 87Sr/86Sr isotope ratios of WCM groundwaters are very uniform and distinct from groundwaters contained in other sedimentary bedrock units. This suggests that 87Sr/86Sr ratios may be a suitable tracer to study hydraulic connectivity of the Walloon Coal Measures with over- or underlying aquifers, although more studies on the systematic are required. Overall, the complexity of recharge processes, aquifer connectivity and within-formation variability confirms that a multi-tracer approach is required to understand aquifer connectivity in these sedimentary basins.
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    Testing atmospheric monitoring techniques for geological storage of CO2
    (Centre for Australian Weather and Climate Research, 2011-11-15) Etheridge, DM; Loh, ZM; Luhar, A; Leuning, R; Steele, LP; Allison, CE; Smith, AM; Hibberd, MF; Feitz, A; Berko, H
    The success of CO2 geological storage in mitigating climate change will depend on its ability to withhold large amounts of CO2 from the atmosphere over centuries or more. Atmospheric techniques have been used to monitor Australia’s first geosequestration project, the CO2CRC Otway Project, since its inception (Etheridge et al. 2011; Jenkins et al. 2011). These techniques have been developed to be sensitive (detecting small potential leakage signals against large and variable background CO2 concentrations and fluxes), specific (attributing variations to sources using chemical and isotopic fingerprints and dispersion modelling) and practical (continuous remote operation) (Leuning et al. 2008; Luhar et al. 2009). A recent stage of the Otway project involved periods of controlled releases of injected gas at the surface that could mimic leakage. This provided a test of the original atmospheric scheme, complemented by additional measurements of CO2 and CH4 concentrations and carbon isotopes of CO2. Based on the experience at Otway and recent results from the new Arcturus baseline atmospheric station in Queensland, this presentation will consider the potential merits of atmospheric techniques for monitoring greenhouse gas emissions from emerging energy technologies such as geosequestration and coal seam methane. © 2011 CSIRO and the Bureau of Meteorology.