b'Geophysics in the surveysNewsThe data were acquired by Daishsat Geodetic Surveyors during August to September 2022. The surveyors used a combination of utility terrain vehicles (UTVs) and a Robinson R44 helicopter to access the proposed sites. The UTVs were used over the AMYAC/pastoral leases portion of the survey, and the helicopter over the FWCAC/Yellabinna Regional Reserve. The Yellabinna Regional Reserve is a protected area of sparsely vegetated red sand dunes necessitating minimal ground disturbance.A data package containing the observed gravity and report was released at Discovery Day 2022. To download the data package, please visit the SARIG catalogue page here. https://catalog.sarig.sa.gov.au/geonetwork/srv/eng/Figure 3.Location map showing proposed magnetotelluric survey route through Victoria and South catalog.search#/metadata/0b25090d- Australiaa898-42a6-9cd3-1e1956c5b7d0same extent as the 2022 seriesof data along the southern profile is South Australian gravity maps,of SA TMI grids, in GDA2020 andcomplete, and preliminary results from updated for 2023 GDA94 coordinate systems, Lambertthe 118 sites were presented at the Conformal Conic projection, .ersSub 22 Conference (http://sub22.w.tas.The 2023 gravity grid of South Australiaformat. currinda.com/). We envisage delivering was gridded from 802 178 ground gravityFiltered grid products derived fromdata from the southern profile in Q1 stations out of a total of 889 282 stationsthe 100 m grid including 1st vertical2023, with models to follow later. An extracted from the South Australianderivative (1VD), upward continuationupdated analysis of the data will be gravity database. All open file surveys(1000 m) and a residual grid derivedpresented at the AEGC 2023 conference.processed to December 2022, includingby subtracting the 1000 m upward the recently acquired GP2 gravity survey incontinued grid from the 100 m gravityData collection for the GP2 project the central Gawler Craton were includedgrid. totalling ~400 MT stations is on-going, in the grid. Duplicate stations and stationsA reliability surface that classifiesand two-thirds of the array data have interpreted as unsuitable for griddingthe gravity station data into nominalbeen acquired to date. The remaining were not included in the processing.station spacing and optimal griddingpart of the survey is scheduled for Within the SA Geodata gravity database,resolution. completion in March-April 2023 across a recently added grid flag has beenAdditional files enabling seamless usethe central Gawler Craton north-west updated for all stations in the database, toof the grids in a range of popular GISof Tarcoola. The survey consists of enable stakeholders to filter out stationssoftware. an array of ~12.5 km spaced MT sites deemed unsuitable for regional gridding.The stations used in the griddingacross the Fowler and Christie Domain, The Bouguer anomaly calculation usedprocess are included in the package asincluding two MT profiles with variable a spherical cap model, and the primaryan ESRI File Geodatabase feature class. site spacing between 1.25 km and 5 units of the grid are m/sec2. km across the main geological strike of For assistance accessing this (or anythe region. One of the aims of the GP2 The gridding process utilised theother geophysical data package), pleaseMT project is to significantly increase supervised variable density griddingcontact firstname.lastname@example.org MT coverage across the underexplored methodology (Katona 2017), whichcentral-western Gawler Craton and shed preserves the optimal grid resolutionlight on the Ni-Cu and gold prospectivity of both coarse and fine spaced gravityMagnetotelluric project progress of the region.stations, smoothly merging variable station densities to a final grid with 100Magnetotelluric data continue to be m cell size. The resulting grid is free ofacquired across two major projectstheReferencegridding artefacts and is robust enoughGawler Phase 2 (GP2) MT grid across the for vertical gradient filtering. central-western Gawler Craton, and theKatona, L., 2017. Gridding of South Delamerian MT profiles along the DCD2Australian Ground Gravity Data, using The 2023 gravity data package, to beseismic lines (Figure 3). the Supervised Variable Density released via SARIG in February, includesMethod. 10.13140/RG.2.2.17491.37923these data products: The Delamerian MT project is nearing completion with ~30 sites awaitingPhilip Heath, Laszlo Katona, Stephan Thiel Grids at 100 m, 200 m, 400 m andacquisition along the western end of theGeological Survey of South Australia 800 m cell size, all clipped to thenorthern profile (Figure 3). CollectionPhilip.Heath@sa.gov.auFEBRUARY 2023 PREVIEW 30'