b'AEGC 2023Short abstractsBroadband Tempest upgrades. Additionally, two proposed broadband MT profiles comprise a total of 173 BBMT with variable spacing between 5 km down to Eric Steele 1.25 km, in sections where mineralisation is expected to occur. The airborne geophysical exploration environment isThe main northern profile crosses the Archean Challenger continuously changing, whether a result of economicAu mine, the proposed Ni-Cu mineral system south-east of circumstances, efficiency improvements or of technicalChallenger and the Tarcoola goldfields in a NW-SE direction. The advancements. The TEMPEST Fixed Wing Electromagneticshorter southern profile runs parallel and focusses on the Ni-Cu Sensing platform undergoes continuous development to meetmineral potential crossing the NE-SW trending gravity high.these requirements in order to remain a leading fixed wing electromagnetic technology for regional and detailed airborne1.60-1.57 Ga suprasubduction zone model for metal surveys around the world as is testified by the ongoing surveysendowment in eastern Australia.being done for both GA and the USGS.Caroline Tiddy and Dave GilesMajor changes have included the aircraft platform on which the system is based, whilst behind the scenes, far more subtleMineral Exploration Cooperative Research Centrechanges have included the transmitter design and transmittedWe propose a model that places development of IOCG (and power, receiver and acquisition systems, thereby improvingporphyry-epithermal) mineralisation at ca. 1.60-1.575 Ga in depth of investigation and near surface resolution. eastern Proterozoic Australia into the context of a modern-A commitment has been made to construct additional TEMPESTday suprasubduction zone. The model is comparable to systems to cater for industry demand. With the advent ofmodern analogues of the Late Cretaceous to Early Eocene additional systems, tests and upgrades of new technologiesLaramide Orogeny in the western United States, present-day would reduce the time to market for these upgrades. slab geometries in the Andes of South America, and by the formation of Cretaceous IOCG and Cu-porphyry deposits in the Recent improvements have included, but are not limited to : Chilean Coastal Cordillera.Increasing the effective bandwidth of the system, which hasThe model depicts a change from a rollback subduction geometry had in impact on the transmitter, receiver and acquisitionand development of extensional basins in the overriding plate systems (~1.67-1.604 Ga) to flat-slab subduction at 1.604 Ga. The change Flexibility in operation of the system in subduction architecture was triggered by the arrival of a Development and improvement of processing algorithms andbuoyant oceanic plateau at the subduction site. Slab-melting and processes metasomatism of the subcontinental lithospheric mantle (SCLM) resulted in eclogitasation and densification of the frontal oceanic New magnetotelluric data across the central-westernslab, slab steepening, sudden upwelling of hot asthenosphere, and production of anhydrous, F-rich, S-poor melts that interacted Gawler Craton - the Gawler Phase 2 project with the metasomatised SCLM. Resultant mafic melts underwent fractionation and eventually formed the dominantly A-type Stephan Thiel 1,2 Hiltaba Suite granites and Gawler Range Volcanics. Fractionated 1 Geological Survey of South Australiamagmas stalled in the upper crust and exsolved volatile-rich 2 The University of Adelaide metalliferous fluids that mixed with meteoric and basinal brings to produce IOCG mineralisation throughout the Olympic Domain, The Gawler Challenge - Next Generation Mineral Systemsincluding the giant Olympic Dam deposit. The downgoing Mapping project (Gawler Phase 2) seeks to collect newslab steepened and retreated, which can be tracked by the geoscience data and capture legacy data to unlock anprogressive westerly to southwesterly younging direction of underexplored part of South Australia. The central-westernthe Hiltaba Suite. Slab retreat resulted in further asthenospheric Gawler Craton was chosen for regional and camp-scale surveysupwelling and progressive development of an asthenospheric with the aim to reduce risk for future exploration and providewedge in a normal subduction geometry. Heat introduced from pre-competitive geoscientific data. The multidisciplinarythe asthenospheric wedge resulted in dehydration of buoyant approach includes geophysical data (gravity, magnetotellurics,oceanic lithosphere and production of S-rich fluids that interacted petrophysics) and the systematic analysis of geochemical/ with the asthenosphere to produce oxidised, S-rich partial melts. geochronological data from existing drill holes. This submissionThe melts interacted with metasomatised SCLM to generate will largely focus on the magnetotelluric (MT) data in contextdominantly I-type magmas and porphyry epithermal systems in with the other data sets. the southwestern Gawler Craton.The new MT data was acquired across a close to even grid of 203 broadband magnetotelluric (BBMT) sites spaced approximatelyInsights for hydrocarbon exploration in igneous 12.5 km across the survey area extending over the Christieprovince: Tectono-magmatic evolution of the Browse and Fowler Domain. The MT grid will ensure the often-lackingBasin, Northwest Shelf.transition from the regional to the camp scale of the mineral systems and plays a key link between isotopic data andKosuke Tsutsui 1 Simon Holford1, Mark Bunch1, Rosalind King1, traditional geophysical targeting techniques. An increase inKen McClay1 and Nick Schofield2electrical conductivity is often associated with an abundance in1 University of Adelaide minor mineral phases associated with past tectonic processes,2 University of Aberdeensuch as sulphides (as a proxy for metal flux), graphite (carbon cycles), and H+ in the crystal lattice of mantle minerals (proxyContinental margins often experience complex geological for metasomatic alteration). history, including multiple rifts, igneous activities, and drastic FEBRUARY 2023 PREVIEW 146'