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  • The Historical Bushfire Boundaries service represents the aggregation of jurisdictional supplied burnt areas polygons stemming from the early 1900's through to 2022 (excluding the Northern Territory). The burnt area data represents curated jurisdictional owned polygons of both bushfires and prescribed (planned) burns. To ensure the dataset adhered to the nationally approved and agreed data dictionary for fire history Geoscience Australia had to modify some of the attributes presented. The information provided within this service is reflective only of data supplied by participating authoritative agencies and may or may not represent all fire history within a state.

  • <div>The Abbot Point to Hydrographers Passage bathymetry survey was acquired for the Australian Hydrographic Office (AHO) onboard the RV Escape during the period 6 Oct 2020 – 16 Mar 2021. This was a contracted survey conducted for the Australian Hydrographic Office by iXblue Pty Ltd as part of the Hydroscheme Industry Partnership Program. The survey area encompases a section of Two-Way Route from Abbot Point through Hydrographers Passage QLD. Bathymetry data was acquired using a Kongsberg EM 2040, and processed using QPS QINSy. The dataset was then exported as a 30m resolution, 32 bit floating point GeoTIFF grid of the survey area.</div><div>This dataset is not to be used for navigational purposes.</div>

  • The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a collaborative national survey that acquires long-period magnetotelluric data on a half-degree grid spacing (approximately 55 km) across the Australian continent. This project aims to map the electrical conductivity/resistivity structure in the crust and mantle beneath the Australian continent. Geoscience Australia has a significant investment in AusLAMP and is a key contributor to the delivery of this national program. Geoscience Australia, in partnership with State and Northern Territory Geological Surveys, has also undertaken regional-scale MT surveys, along onshore deep reflection seismic transects and in potential mineral and energy provinces across the country. The targeting signal range is 10 KHz – 1000 s, which provide an investigation depth from tens of metres to tens of kilometres. These data provide new insights into basement architecture and resource potential in these regions. We will present some new models and results from AusLAMP data and regional survey data, showing a remarkable correlation between conductive anomalies, crustal-scale boundaries and the distribution of giant mineral deposits. For example, the Carpentaria Conductivity Anomaly at the eastern margin of the Mount Isa Province characterises the position and geometry of the ancient Gidyea Suture Zone. The distribution of known gold and copper deposits shows a close spatial correlation with the suture zone, indicating that this structure is potentially a fundamental control on IOCG deposits in its vicinity. The implication is that crustal-penetrating structures act as potential pathways for fluid movement to form mineral deposits in the upper crust. This Abstract was submitted/presented to the Biennial Meeting of the Specialist Group for Tectonics and Structural Geology (SGTSG) and the Specialist Group in Solid Earth Geophysics (SGSEG), Convergence on the Coast, 18-22 November 2019 Port Lincoln, South Australia

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    Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This NTGS Pedirka Gravity 202381 Geoid Elevation is elevation data for the NTGS Pedirka Gravity Survey (P202381). This survey was acquired under the project No. 202381 for the geological survey of NT. The grid has a cell size of 0.00944 degrees (approximately 1000m). This grid contains the ground elevation relative to the geoid for the NTGS Pedirka Gravity Survey (P202381). It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.

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    The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This Tasmanian Tiers Airborne Magnetic, Radiometric and Digital Elevation Survey, TAS, 2021, (P5003), Block 1, radiometric line data were acquired in 2021 by the TAS Government, and consisted of 32951 line-kilometres of data at 200m line spacing and 80m terrain clearance.

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    The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This Tasmanian Tiers Airborne Magnetic, Radiometric and Digital Elevation Survey, TAS, 2021, (P5003), Block 4, radiometric line data were acquired in 2021 by the TAS Government, and consisted of 32951 line-kilometres of data at 200m line spacing and 80m terrain clearance.

  • The footprint of a mineral system is potentially detectable at a variety of scales, from ore deposits to the Earth’s crust and lithosphere. Magnetotellurics is one of few techniques that can provide multi-scale datasets to understand mineral systems. We have used long-period data from the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) as a first-order reconnaissance survey to resolve large-scale lithospheric architecture for mapping areas of mineral potential in northern Australia. The 3D resistivity model reveals a broad conductivity anomaly extending from the Tennant Region to the Murphy Province in the lower crust and upper mantle, representing a potential fertile source region for mineral systems. Results from higher-resolution infill magnetotelluric survey reveal two prominent conductors in the resistive host whose combined responses result in the lithospheric-scale conductivity anomaly mapped in the AusLAMP model. Most importantly, conductive structures indicate a “favorable” crustal architecture linking the lower, fertile source regions with depositional sites in the upper crust. This observation strongly suggests that the major faults are deep-penetrating structures that potentially acted as pathways for transporting metalliferous fluids to the upper crust where they could form mineral deposits. This result and its integration with other datasets suggest high prospectivity for major mineral deposits in the vicinity of these major faults. In addition to this contribution, interpretation of high-frequency magnetotelluric data helps characterise cover and assist with stratigraphic drill targeting which, in turn, will validate the models and improve our understanding of basement geology, cover sequences and mineral potential. This study demonstrates that integration of geophysical data from multi-scale surveys is an effective approach to scale reduction during mineral exploration in covered terranes with limited geological knowledge. <b>Citation: </b> Wenping Jiang, Jingming Duan, Michael Doublier, Andrew Clark, Anthony Schofield, Ross C Brodie, James Goodwin, Application of multiscale magnetotelluric data to mineral exploration: an example from the east Tennant region, Northern Australia, <i>Geophysical Journal International</i>, Volume 229, Issue 3, June 2022, Pages 1628–1645, https://doi.org/10.1093/gji/ggac029

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    Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. These line dataset from the Tasmanian Tiers Magnetic and Radiometric Survey, 2021 survey were acquired in 2021 by the TAS Government, and consisted of 32951 line-kilometres of data at 200m line spacing and 80m terrain clearance.

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    Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This Tasmanian Tiers Airborne Magnetic, Radiometric and Digital Elevation Survey, TAS, 2021, (P5003), radar digital elevation model grid is elevation data for the Tasmanian Tiers Magnetic and Radiometric Survey, 2021. This survey was acquired under the project No. 5003 for the geological survey of TAS. The grid has a cell size of degrees (approximately 40m). This grid contains the ground elevation relative to the geoid for the Tasmanian Tiers Magnetic and Radiometric Survey, 2021. It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.

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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This NTGS Pedirka Gravity 202381 Complete Spherical Cap Bouguer Anomaly 1VD CSCBA267um is the first vertical derivative of the complete spherical cap Bouguer anomaly grid for the NTGS Pedirka Gravity Survey (P202381). This gravity survey was acquired under the project No. 202381 for the geological survey of NT. The grid has a cell size of 0.00944 degrees (approximately 1000m). A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid. A total of 11443 gravity stations at a spacing between 2000m and 4000m were acquired to produce this grid.