Abstract We use random resistor network models to explore the relationship between electrical resistivity and permeability in a fracture filled with an electrically conductive fluid. Fluid flow current are controlled by both distribution volume of pore space. Therefore, aperture fractures must be accurately modeled order realistically represent their hydraulic properties. have constructed surface pairs based on characteristics measured rock samples. these construct networks variable...

Abstract Orogenic gold deposits provide a significant source of the world’s and form along faults over wide range crustal depths spanning sub-greenschist to granulite grade faces, but remains poorly understood. In this paper we compiled thirty years long-period magnetotelluric (MT) geomagnetic depth sounding (GDS) data across western Victoria south-eastern South Australia that have sensitivity electrical resistivity crust mantle, which in turn depend on past thermal fluid processes. This...

We present a resistivity model of the southern Tasmanides southeastern Australia using Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data. Modelled lower crustal conductivity anomalies resemble concentric geometries revealed in upper crust by potential field and passive seismic These are key part architecture predicted Lachlan Orocline for evolution Tasmanides, which Proterozoic Selwyn Block drives oroclinal rotation against eastern Gondwana margin during Silurian...

The clean energy transition will require a vast increase in metal supply, yet new mineral deposit discoveries are declining, due part to challenges associated with exploring under sedimentary and volcanic cover. Recently, several case studies have demonstrated links between lithospheric electrical conductors imaged using magnetotelluric (MT) data deposits, notably Iron Oxide Copper Gold (IOCG). Adoption of MT methods for exploration is therefore growing but the general applicability...

Abstract The thermochemical structure of the lithosphere controls melting mechanisms in mantle, as well location volcanism and ore deposits. Obtaining reliable images structure, its complex interactions with asthenosphere, requires joint inversion multiple data sets their associated uncertainties. In particular, combination seismic velocity electrical conductivity, along proxies for bulk composition elusive minor phases, represents a crucial step toward fully understanding large‐scale...

Abstract The resistivity and permeability of 3‐D fracture networks have been modeled as the fractures within these are incrementally opened. In models, ratio rock to that fluid is 10 4 , 1 × −18 m 2 . changes in both depend on characteristics network itself such density, well aperture distribution individual fractures. dense where density constant α equal 30, a percolation threshold can be defined terms mean aperture, below which close their matrix values. At threshold, change 0.02 mm by...

We present composition-based estimates and the first national maps of thermal conductivity heat production New Zealand's basement terranes. Our are based on a geometric mean four mineral groupings, quartz, olivine, pyroxene other (expected to be predominantly feldspars). Thermal conductivities each these groups derived from regression in log space as function proportion groups. compare our mixing model with previously developed using major oxide composition, find both models work well for...

We present 1D anisotropic inversion of magnetotelluric (MT) data as a potential tool for mapping structural permeability in sedimentary basins. Using inversions 171 site, broadband MT set from the Koroit region Otway Basin, Victoria, Australia, we have delineated an electrically layer at approximately 2.5 to 3.5 km depth. The anisotropy strike is consistent between stations 160° east north. depth corresponds top Lower Cretaceous Crayfish Group, and factor increases west east. interpret...

Deep seismic reflection surveys in north Queensland that were collected 2006 and 2007 discovered a previously unknown sedimentary basin, now named the Millungera Basin, which is completely covered by thin succession of sediments Jurassic–Cretaceous, Eromanga-Carpentaria Basin. Interpretation regional aeromagnetic data suggests basin could have areal dimensions up to 280 km 95 km. Apart from geophysical data, virtually no confirmed geological information exists on basin. To complement new...

Abstract We present a 3‐D inversion of magnetotelluric data acquired along 340‐km transect in Central Australia. The results are interpreted with coincident deep crustal seismic reflection survey and magnetic inversion. profile crosses three Paleoproterozoic to Mesoproterozoic basement provinces, the Davenport, Aileron, Warumpi Provinces, which overlain by remnants Neoproterozoic Cambrian Centralian Surperbasin, Georgina Amadeus Basins, Irindina Province. shows conductors near base Province...

The magnetotelluric (MT) method is increasingly being applied to mineral exploration under cover with several case studies showing that systems can be imaged from the lower crust near surface. Driven by this success, Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) delivering long-period data on a 0.5° grid across Australia, and derived continental scale resistivity models are helping drive investment in frontier areas. Part of includes higher-resolution broadband MT...

Abstract To investigate the thermal structure of central Te Riu a Māui/Zealandia continent we estimate depth to base magnetic sources (DBMS), using an updated compilation data. We calculate thousands power spectral density estimates and solve analytic solution for fractal distribution magnetization Bayesian method constrained by sediment thickness model. Our DBMS results are broadly similar global model yet show complex relationships with independent models crust elastic thicknesses,...

We present models of random resistor networks to relate electrical resistivity fracture permeability in the upper crust. In this approach, crust is modelled as a network resistors that are randomly assigned be either electrically and hydraulically conductive or resistive based on network-wide probability connection. presented here, resistance values constant diameter 1 mm fluid 0.1 Ωm, with variable fault length distributions probabilities have found very sensitive both these parameters,...

Ground source heat pumps (GSHP) are one of the fastest growing applications renewable energy in world, with increases installed capacity over 10% per annum between 1995 and 2005 (Rybach, 2005). GSHP systems widespread overseas, particularly USA Europe, a total 7.2 GWth (47% world total) USA, 3.84 (25%) Sweden. In comparison, Australia lags behind 5.5 MWth, (0.036%

We use resistor network models to explore the relationship between electrical resistivity and permeability in fractures filled with an electrically conductive fluid. The fracture aperture distribution is determined by generating surface pairs that are constructed based on characteristics measured rock samples. these generate solve networks variable hydraulic resistance. incrementally increased, analyse changes both properties as a fault opened. At small apertures, conductivity increase...

The magnetotelluric (MT) method is becoming more widely used in the geoscience community as it becomes increasingly recognised a useful exploration tool. However, while analysis and inversion tools available to MT have increased over recent years, software work with these still somewhat limited often costly comparison some of mature techniques like gravity, magnetics seismic.The MTpy python library open source that aims assist practitioners carrying out processing steps need be carried data...

Magnetotellurics (MT) is a passive geophysical method that uses natural time variations of the Earth’s magnetic and electric fields to measure electrical resistivity sub-surface.The elec...

We present inversion results for a 100 site, broadband magnetotelluric (MT) survey in the Penola Trough, Otway Basin, South Australia. The Trough is host to several petroleum reservoirs and has more recently been target unconventional geothermal exploration. two interpretations of MT data. A 1D anisotropic interpretation, where anisotropy determined within Basin sequence basement northeastern fits impedance tensor well. However, strike inconsistent with known orientation electrically...

We present 1D anisotropic inversions of magnetotelluric data in two regions the Otway Basin; Koroit, Victoria, and Penola, South Australia. In Koroit region we have delineated an electrically layer at approximately 2.5 to 3.5 km depth; this corresponds upper part Lower Cretaceous Crayfish Group, a known reservoir unit. The anisotropy strike is consistent between stations 160° east north. interpret as resulting from pervasive NNW oriented, fluid-filled fractures, enhanced bulk electrical...

The Geophysics and Modelling team at the Geological Survey of New South Wales (GSNSW) is playing a key role in tectonic interpretation Tasmanides eastern Australia through an ongoing ...