2014
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The mechanism and uplift history of Australia's southeastern highlands has long been debated. End member models account for the topography as a down warped relict of an ancient plateau or a consequence of uplift associated with either rifting along the eastern margin or Cenozoic volcanism. All of these models assume present-day elevation is a consequence of isostatic equilibrium at the base of the crust. An analysis of the relationship between gravity and topography in the spectral domain shows the admittance at wavelengths longer than those controlled by flexure is ~50 mgal km-1. This value is characteristic of dynamic support arising from thermal anomalies beneath the plate predicted by multiple mantle convection simulations and observed over Africa, Antarctic and the Pacific Ocean. Division of long-wavelength filtered gravity by this admittance value suggests the southeastern highlands are supported by 400-900 m. The morphological expressions of this support are the Great Escarpment and major knick zones on rivers such as the Snowy. The temporal evolution of this support can be determined by exploiting longitudinal river profiles since their shape is controlled by uplift and modulated by erosion. By applying the well-known detachment limited stream power law to model erosion uplift histories can be extracted provided erosional parameters can be constrained. By calibrating the erosional parameters using incision rates along the Tumut River and Tumbarumba Creek as well as palaeoelevations of basalt flows the uplift history of the southeastern highlands can ascertained directly from the landscape. Our results show uplift of the southeastern highlands occurred in two phases associated with Cretaceous age rifting resulting in Tasman Sea floor spreading and Cenozoic volcanism. The latter event accounts for the observed amplitude of present-day dynamic topography thereby suggesting Cenozoic uplift occurred from an unperturbed isotactic elevation. Since Cretaceous rifting along the southeastern margin occurred over a cool mantle given the oldest oceanic floor is thinner than the global average it is unlikely that rift related uplift is a consequence of mafic underplating. The most likely driver for this earlier phase of uplift is emergence of eastern Australia from a dynamically drawdown position which has been inferred to explain the widespread mid-Cretaceous marine inundation of Eastern Australia. Therefore it is likely that both uplift events are controlled by changes in the thermal state of the mantle as opposed to changes in crustal thickness and density. This history of vertical motions is consistent with long-term river incision rates, basin sequence stratigraphy and thermochronological studies.
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This collaborative project between Geoscience Australia (GA) and CSIRO aims to use physicochemical measurements, collected from surface overbank sediments as part of the National Geochemical Survey of Australia (NGSA) project, to help validate the ASTER multispectral geoscience maps of Australia. Both data sets have common information including that related to the surface abundance of silica, aluminium, iron, clay, sand and volatiles (including carbonate). The ASTER geoscience maps also provide spatial information about trends of mineral composition, which are potentially related to pH and oxidation state.
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This report provides background information about the Ginninderra controlled release Experiment 2 including a description of the environmental and weather conditions during the experiment, the groundwater levels and a brief description of all the monitoring techniques that were trialled during the experiment. Release of CO2 began 26 October 2012 at 2:25 PM and stopped 21 December 2012 at 1:30 PM. The total CO2 release rate during Experiment 2 was 218 kg/d CO2. The aim of the second Ginninderra controlled release was to artificially simulate the leakage of CO2 along a line source, to represent leakage along a fault. Multiple methods and techniques were then trialled in order to assess their abilities to: - detect that a leak was present - pinpoint the location of the leak - identify the strength of the leak - monitor how the CO2 behaves in the sub-surface - assess the effects it may have on plant health Several monitoring and assessment techniques were trialled for their effectiveness to quantify and qualify the CO2 that was release. This experiment had a focus on plant health indicators to assess the aims listed above, in order to evaluate the effectiveness of monitoring plant health and the use of geophysical methods to identify that a CO2 leak may be present. The methods are described in this report and include: - soil gas - airborne hyperspectral surveys - plant health (PhenoMobile) - soil CO2 flux - electromagnetic (EM-31) - electromagnetic (EM-38) - ground penetrating radar (GPR) This report is a reference guide to describe the Ginninderra Experiment 2 details. Only methods are described in this report with the results of the study published in conference papers and future journal articles.
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1 map showing the Acreage Release Title AC15-3 in the area of Overlapping Jurisdiction in the Perth Treaty. Requested by RET August 2014. LOSAMBA register 707
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Since the early 2000s Geoscience Australia has been compiling new seamless national continental scale geological maps. The first edition of a seamless 1:1 000 000 scale surface geology map of Australia was released in 2008 [1] and the latest edition released in 2012 [2]. This work draws extensively from available geological mapping in Australia, primarily at the scales of 1:250 000 and 1:100 000 with the addition of some special regional scale maps. The digital GIS dataset is linked to other national geoscience databases at Geoscience Australia, including the Australian Stratigraphic Units Database. In September 2013, Geoscience Australia released the first national Geological Provinces dataset [3]. Geoscience Australia's Geological Provinces Database captures detailed information such as age, stratigraphy, lithology, mineral resources, and relations to other provinces. It also captures outlines of the full (ie, concealed) extent and outcropping extent of a province. As part of Geoscience Australia's contribution to Searching the Deep Earth [4], current continental scale digital geological mapping in Geoscience Australia includes production of a new national bedrock geological map at 1:2 500 000 scale with stratigraphic units information that can be linked with other national geoscience databases, basement geology, and a national regolith landforms coverage. Looking ahead, a goal is to produce seamless, continental scale basement or 'solid' geology maps for a variety of depth/time slices. A recent step towards this goal has been the production of a map of Mesoproterozoic and older basement geology for a large region of central Australia, from the eastern Yilgarn Craton of Western Australia across the Musgrave and southern Arunta Provinces to the Queensland border.
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1 map showing the Acreage Release Title W15-2 in the area of Overlapping Jurisdiction in the Perth Treaty. Requested by RET August 2014. LOSAMBA register 707
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AAM was engaged by DPIPWE to acquire LiDAR data over several coastal areas of Tasmania during March and April 2014. South Port comprises approximately 5.07 km²
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This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP), and thin section descriptions for nine samples of plutonic and volcanic rocks of the New England Orogen, New South Wales. The work was carried out under the auspices of the National Geoscience Accord, as a component of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) during the reporting periods 2010/11 and 2011/12.
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This report outlines the levelling survey completed during the visit to Lautoka, Fiji from 17th to 24th February 2013.
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This report outlines the high precision level survey completed between the SEAFRAME tide gauge and continuous GPS station in Tarawa, Kiribati from 23 - 30 April 2012.