Legacy product - no abstract available

Conodont Biostratigraphy of the upper Devonian reef complexes of the Canning Basin, Western Australia

This GA Record contains papers presented at the Inversion Forum 2013, held on August 10 2013 immediately prior to the ASEG-PESA 2013 Conference, Melbourne, Victoria, Australia.

A card to illustrate the GA Education Centre, and the activities it can provide to school groups.

Geoscience Australia undertook seabed mapping surveys in the eastern Bonaparte Gulf in 2009/2010 to deliver integrated information relevant to marine biodiversity conservation and offshore infrastructure development. The survey objectives were to characterise the physical, chemical and biological properties of the seabed, document potential geohazards and to identify unique or sensitive benthic habitats and collect baseline information on these habitats. Different clustering methods were applied to a 124 sample dataset comprising 74 physical and geochemical variables which describe organic matter (OM) reactivity/quantity/source and geochemical processes relevant to biodiversity. Infauna data were used to assess different groupings because they are an important food source for epibenthic crustaceans and fish and purveyors of ecosystem services including nutrient cycling and mineralisation. Clusters based on physical/geochemical data discriminated infauna better than geomorphic features. Major variations amongst clusters included grainsize and a cross-shelf transition in from authigenic-Mn /As enrichments (inner shelf) to authigenic-P enrichment (outer shelf) which relate to energy levels and sediment oxygen status. Groups comprising raised features had the highest reactive OM concentrations (e.g. based on low chlorin indices and C:N-ratios, and high k) and benthic algal -13C signatures. Surface area normalised OM concentrations higher than continental shelf norms were observed in association with: (i) low -15N, inferring Trichodesmium input; and (ii) pockmarks. The pockmarks are shown to impart bottom-up controls on seabed chemistry and cause inconsistencies between bulk and pigment OM pools. The geochemical data and clustering methods provide insight into ecosystem processes which influence biodiversity patterns in the region. Low Shannon-Wiener diversity occurred in association with low porewater pH and evidence for low sediment redox status and high energy levels, while the highest beta-diversity was observed at euphotic depths. Pair-wise ANOSIM results for infauna are brought together in a summary model which highlights the influence of the clusters on beta diversity.

Poster prepared for International Association of Hydrogeologists Congress 2013 Surface-groundwater interactions are often poorly understood. This is particularly true of many floodplain landscapes in Australia, where there is limited mapping of recharge and discharge zones along the major river systems, and only generalised quantification of hydrological fluxes based on widely spaced surface gauging stations. This is compounded by a lack of temporal data, with poor understanding of how surface-groundwater interactions change under different rainfall, river flow and flood regimes. In this study, high resolution LiDAR, in-river sonar, and airborne electromagnetic (AEM) datasets (validated by drilling) have been integrated to produce detailed 3-dimensional mapping that combines surface geomorphology and hydrogeology. This mapping enables potential recharge zones in the river and adjacent landscape to be identified and assessed under different flow regimes. These potential recharge zones and groundwater flow pathways were then compared against the spatial distribution of discontinuities in near-surface and deeper aquitard layers derived from the AEM interpretation. These 3D mapping constructs provide a framework for considering groundwater processes. Hydrochemistry data, allied with hydraulic data from a bore monitoring network, demonstrate the importance of recharge during significant flood events. In many places, the AEM data also affirm the spatial association between fresher groundwater resources and sites of river and floodplain leakage. At a more localised scale, hydrogeochemical data allows discrimination of lateral and vertical fluxes. Overall, this integrated approach provides an important conceptual framework to constrain hydrogeological modelling, and assessments of sustainable yield. The constructs are also invaluable in targeting and assessing managed aquifer recharge (MAR) options.

To enable more efficient operation of the SLR system at Yarragadee after the installation of the AuScope VLBI antenna, several modifications have been made to the standard MOBLAS configuration. Many of these modifications have improved operator safety and job satisfaction, but have not impacted at all on the MOBLAS data quality standards. This poster demonstrates the changes made and ideas for future enhancements.

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available