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  • This service has been created specifically for display in the National Map and the chosen symbology may not suit other mapping applications. The Australian Topographic web map service is seamless national dataset coverage for the whole of Australia. These data are best suited to graphical applications. These data may vary greatly in quality depending on the method of capture and digitising specifications in place at the time of capture. The web map service portrays detailed graphic representation of features that appear on the Earth's surface. These features include the administration boundaries from the Geoscience Australia 250K Topographic Data, including state forest and reserves.

  • We collected 38 groundwater and two surface water samples in the semi-arid Lake Woods region of the Northern Territory to better understand the hydrogeochemistry of this system, which straddles the Wiso, Tennant Creek and Georgina geological regions. Lake Woods is presently a losing waterbody feeding the underlying groundwater system. The main aquifers comprise mainly carbonate (limestone and dolostone), siliciclastic (sandstone and siltstone) and evaporitic units. The water composition was determined in terms of bulk properties (pH, electrical conductivity, temperature, dissolved oxygen, redox potential), 40 major, minor and trace elements as well as six isotopes (δ18Owater, δ2Hwater, δ13CDIC, δ34SSO4=, δ18OSO4=, 87Sr/86Sr). The groundwater is recharged through infiltration in the catchment from monsoonal rainfall (annual average rainfall ~600 mm) and runoff. It evolves geochemically mainly through evapotranspiration and water–mineral interaction (dissolution of carbonates, silicates, and to a lesser extent sulfates). The two surface waters (one from the main creek feeding the lake, the other from the lake itself) are extraordinarily enriched in 18O and 2H isotopes (δ18O of +10.9 and +16.4 ‰ VSMOW, and δ2H of +41 and +93 ‰ VSMOW, respectively), which is interpreted to reflect evaporation during the dry season (annual average evaporation ~3000 mm) under low humidity conditions (annual average relative humidity ~40 %). This interpretation is supported by modelling results. The potassium (K) relative enrichment (K/Cl mass ratio over 50 times that of sea water) is similar to that observed in salt-lake systems worldwide that are prospective for potash resources. Potassium enrichment is believed to derive partly from dust during atmospheric transport/deposition, but mostly from weathering of K-silicates in the aquifer materials (and possibly underlying formations). Further studies of Australian salt-lake systems are required to reach evidence-based conclusions on their mineral potential for potash, lithium, boron and other low-temperature mineral system commodities such as uranium. <b>Citation:</b> P. de Caritat, E. N. Bastrakov, S. Jaireth, P. M. English, J. D. A. Clarke, T. P. Mernagh, A. S. Wygralak, H. E. Dulfer & J. Trafford (2019) Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia, <i>Australian Journal of Earth Sciences</i>, 66:3, 411-430, DOI: 10.1080/08120099.2018.1543208

  • This service provides Australian surface hydrology, including natural and man-made features such as water courses (including directional flow paths), lakes, dams and other water bodies. The information was derived from the Surface Hydrology database, with a nominal scale of 1:250,000. The National Basins and Catchments are a national topographic representation of drainage areas across the landscape. Each basin is made up of a number of catchments depending on the features of the landscape. This service shows the relationship between catchments and basins. The service contains layer scale dependencies.

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    The Digital Elevation Model represents ground surface topography between points of known elevation. The elevation data was calculated using the altimeters and Global Positioning System (GPS) sensor used for the benefit of airborne magnetic and radiometric data on the same survey. The elevation is the height relative to the Australian Height Datum GDA94 (AUSGEOID09). The processed elevation 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 NSW DMR, Discovery 2000 Area N, Menindee, NSW, 1999 survey were acquired in 1999 by the NSW Government, and consisted of 41736 line-kilometres of data at 150m line spacing and 40m terrain clearance.

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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 NSW DMR, Discovery 2000 Area N, Menindee, NSW, 1999 survey were acquired in 1999 by the NSW Government, and consisted of 41736 line-kilometres of data at 150m line spacing and 40m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

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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 NSW DMR, Discovery 2000 Area N, Menindee, NSW, 1999 (P744), radiometric line data, AWAGS levelled were acquired in 1999 by the NSW Government, and consisted of 41736 line-kilometres of data at 150m line spacing and 40m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

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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 NSW DMR, Discovery 2000 Area N, Menindee Central, NSW, 1999 (P744), radiometric line data, AWAGS levelled were acquired in 1999 by the NSW Government, and consisted of 41736 line-kilometres of data at 150m line spacing and 40m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

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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 GSNSW Exploration NSW Area M Kayrunnera elevation grid geodetic is elevation data for the NSW DMR, Area M, Kayrunnera(Milparinka, Cobham Lk, White Cl.), NSW, 1999. This survey was acquired under the project No. 745 for the geological survey of NSW. The grid has a cell size of 0.00048 degrees (approximately 50m). This grid contains the ground elevation relative to the geoid for the NSW DMR, Area M, Kayrunnera(Milparinka, Cobham Lk, White Cl.), NSW, 1999. 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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    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. This magnetic grid has a cell size of 0.00048 degrees (approximately 50m).The data are in nanoTesla (or nT). The data used to produce this grid was acquired in 1999 by the NSW Government, and consisted of 55448 line-kilometres of data at 250m line spacing and 60m terrain clearance. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. The VRTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model using a data representative date and elevation representative of the survey.

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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 NSW DMR, Area M, Kayrunnera(Milparinka, Cobham Lk, White Cl.), NSW, 1999 (P745), radiometric line data, AWAGS levelled were acquired in 1999 by the NSW Government, and consisted of 55448 line-kilometres of data at 250m line spacing and 60m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.