From 1 - 10 / 28
  • 40 years atmospheric reanalysis for Australia region. http://www.ecmwf.int/products/data/archive/descriptions/e4/index.html

  • X3D Model and Visualisation of the Hydrostratigraphic System in the Hodgson and Kings Creek Sub-Catchments

  • <p>The footprint of a mineral system is potentially detectable at a variety of scales, from the ore deposit to the Earth’s crust and lithosphere. In order to map these systems, Geoscience Australia has undertaken a series of integrated studies to identify key regions of mineral potential using new data from the Exploring for the Future program together with legacy datasets. <p>The recently acquired long-period magnetotellurics (MT) data under the national-scale AusLAMP project mapped a lithospheric scale electrical conductivity anomaly to the east of Tennant Creek. This deep anomaly may represent a potential source region for mineral systems in the crust. In order to refine the geometry of this anomaly, high-resolution broadband and audio MT data were acquired at 131 stations in the East Tennant region and were released in Dec 2019 (http://dx.doi.org/10.26186/5df80d8615367). We have used these high-resolution MT data to produce a new 3D conductivity model to investigate crustal architecture and to link to mineral potential. The model revealed two prominent conductors in the resistive host, whose combined responses link to the deeper lithospheric-scale conductivity anomaly mapped in the broader AusLAMP model. The resistivity contrasts coincide with the major faults that have been interpreted from seismic reflection and potential field data. Most importantly, the conductive structures extend from the lower crust to near-surface, strongly suggesting that the major faults are deep penetrating structures that potentially act as pathways for transporting metalliferous fluids to the upper crust where they can form mineral deposits. Given the geological setting, these results suggest that the mineral prospectivity for iron oxide copper-gold deposits is enhanced in the vicinity of the major faults in the region. <p>This release package includes the 3D conductivity model produced using ModEM code in sGrid format and Geo-referenced depth slices in .tif format.

  • Communities and their economic activity rely heavily on critical infrastructure. Utility infrastructure facilities are usually comprised of a range of interconnected components characterised by varying degrees of operational criticality and vulnerability to earthquake ground motion. The severity of damage to these components in an earthquake has complex implications for post-event functionality, repair cost and recovery timeframe of facilities. This paper describes how an integration of physical component vulnerability, associated component functionality and a system model of the facility have been used to understand the seismic vulnerability and mitigation opportunities associated with a thermal power station. System behaviour of the facility has been analysed using a network model to evaluate facility performance and to assess component criticality. An application has been developed that integrates these elements in a Monte Carlo simulation that enables the outcomes of a broad set of events to be assessed, and is used to develop facility level fragility models. Finally, the benefits of this approach to the process of assessment of vulnerability of legacy assets and identification of mitigation opportunities are demonstrated.

  • This release comprises the 3D geological model of the Yilgarn-Officer-Musgrave (YOM) region, Western Australia, as Gocad voxets and surfaces. The YOM 3D geological model was built to highlight the broad-scale crustal architecture of the region and extends down to 60 km depth.

  • The depth to Proterozoic basement surface was constructed in order to delineate the thickness of Phanerozoic and more recent cover material. The "basement" refers to the Neoproterozoic and older rocks underlying the Canning Basin. The 3D surface was constructed using GoCad software and constrained by drill-hole data, Euler depth solutions and forward modelling using magnetic data, and interpreted depths from three seismic lines crossing the Waukalycarly Embayment. The depth to basement surface should be used as a guide. With the exception of the drill-hole data, there are uncertainties involved in estimating the depths based on the magnetic methods (Euler depth solutions and forward modelling), as well as the seismic data.

  • This product is a rendered 3D model of one of the five ACT fossil emblem candidates, the brachiopod Retziella capricornae. The format of the file is ply. or Polygon File Format, and it is designed to store 3D data. The model requires no post-scanning manipulation as it is already complete. The purpose of this is to make this file format publicly available to local school communities so they can 3D print the fossil emblems themselves and engage students with Earth science related topics. <b>Acknowledgement:</b> Computed Tomography (CT) Scans and models generated at <a href="https://ctlab.anu.edu.au/">CTLab</a> - National Laboratory for X-Ray Micro Computed Tomography, Research School of Physics, The Australian National University (ANU), Canberra.

  • It is with great interest that we read the paper by Mueller (2015) who proposes that the majority of small pockmarks with diameters less than about 10 m on the northwest shelf of Australia may be of biotic origin, created by the fish Epinephelus, the Grouper. This hypothesis is based on a spatial association between pockmarks and Epinephelus at a number of sites on the northwest shelf and elsewhere around Australia, and on recent work undertaken on the habitats and observed behaviours of grouper fish in the Gulf of Mexico who excavate sediment from pre-existing solution cavities (Coleman et al., 2010; Wall et al., 2011). However, we contend that critical details have not been taken into account as part of Mueller's (2015) hypothesis, and additional consideration of existing geologic, geomorphic, sedimentologic and geochemical information is required. To make the science more robust, here we present a more comprehensive overview of the information available.

  • The project modelled the tsunami inundation to selected sites in South East Tasmania based on a Mw 8.7 earthquake on the Puysegur Trench occurring at Mean Sea Level. As yet, there is no knowledge of the return period for this event. The project was done in collaboration with Tasmania State Emergency Services as part of a broader project that investigated tsunami history through palaeotsunami investigations. The intent was to build the capability of staff within Tasmania Government to undertake the modelling themselves. Formal modelling of the tsunami inundation occurred through national project funding.

  • As part of Geoscience Australia’s Exploring for the Future Program, Broadband and Audio Magnetotelluric (MT) data were acquired at 131 stations in the East Tennant region, Northern Territory, in 2019. This survey aimed to characterise major crustal structures, to map cover thickness to assist in stratigraphic drill targeting, and to help understand mineral potential in the region. The data package was released in December 2019 (http://dx.doi.org/10.26186/5df80d8615367) and the 3D resistivity model was released in March 2020 (https://pid.geoscience.gov.au/dataset/ga/135011). We applied a probabilistic approach to inverting high-frequency MT data for cover thickness estimation using the 1D Rj-McMCMT code, newly developed in Geoscience Australia. The inversion employs multiple Markov chains in parallel to generate an ensemble of millions of resistivity models that adequately fit the data given the assigned noise levels. The algorithm uses trans-dimensional Markov chain Monte Carlo techniques to solve for a probabilistic resistivity-depth model. Once the ensemble of models is generated, its statistics are analysed to assess the posterior probability distribution of the resistivity at any particular depth, as well as the number of layers and the depths of the interfaces. This stochastic approach gives a thorough exploration of the model space and a more robust estimation of uncertainty than deterministic methods allow. This release package includes the results of probabilistic inversion of Audio Magnetotelluric data at the 131 stations. They can be used to estimate cover thickness for drill site planning, and to map the base of geological basins in the region. Model data files are large, but can be made available on request to clientservices@ga.gov.au.