b'Geophysics in the surveysNewsMineral Resources Tasmania: Significant increase in data coverageTasmanias coverage of high qualityTasmanian Government throughcover, as well as more subtle contrasts magnetic and radiometric data hasMineral Resources Tasmania. Thewithin the mafic igneous Jurassic increased by over 10 000 squaredata are now available for downloaddolerite and Cenozoic basalt. Analysis kilometres (approximately 20%) aftervia Geoscience Australia (http://pid. of these features in conjunction with completion of a new airborne surveygeoscience.gov.au/dataset/ga/147455)corresponding anomalous magnetic over south-eastern Tasmania. The newand MRT (https://www.mrt.tas.gov. signatures may yield implications for data were acquired entirely with anau/webdoc2/app/default/airborne_ rare earth as well as bauxite and natural AS350B2 (Squirrel) helicopter from 20survey_detail?id=2087). hydrogen prospectivity.March to 23 June 2022, along 57 709 line km at 200 m line spacing and an averageBoth radiometric and magnetic data setsThis vastly improved characterisation terrain clearance of 95 m. Variance ofare extremely feature-rich. Considerableof the cover will also contribute to the latter from a nominal clearance ofinternal property variation is apparent inreduced risk for exploration targeting 80 m was necessitated by terrain thataddition to numerous multiple orientedthe underlying geology, which is known is extremely challenging by Australianfaults dissecting the Jurassic doleriteto contain correlatives of the highly standards, in addition to constraintsintrusives which dominate the magneticprospective Mount Read Volcanics.associated with overflying more thanresponse (Figure 1). The origin of more 275 000 people (approximately halfsubdued curvilinear magnetic featuresReferenceTasmanias population) and numerouswithin Devonian granite on the Freycinet equine properties. Peninsula is less certain, but they mayMiller HG and Singh V, 1994. Potential correspond to an older dolerite (latefield tilta new concept for location The survey was primarily supervisedDevonian-Carboniferous) dyke swarm. of potential field sources. Journal of by Geoscience Australia and largelyApplied Geophysics 32: 213-217.funded by the CommonwealthThe new radiometric data (Figure 2) Governments Exploring for the Futurehave effectively mapped the wideMark Duffett initiative, with additional financialrange of lithostratigraphic variationMineral Resources Tasmania and in-kind contributions from thewithin the Permo-Triassic sedimentarymark.duffett@stategrowth.tas.gov.auFigure 1.Total magnetic intensity stitch incorporating the new survey data,Figure 2.Radiometric data from the new survey processed to equivalent outlined in green. Image is histogram-equalised with tilt angle intensity overlay.ground concentrations of potassium, thorium and uranium, merged into the The tilt angle calculation (Miller and Singh, 1994) results in some artefacts inexisting state coverage, with which the new data overlaps to the north and west. areas of lower quality data offshore. Faded background image is histogram-equalised magnetics with tilt angle intensity shading (as in Figure 1).FEBRUARY 2023 PREVIEW 26'