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2-D Audiomagnetotelluric Modelling of Ore Deposits - Improvements of Model Constraints by Inclusion of Borehole Measurements
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, EAGE/DGG Workshop on Deep Mineral Exploration, Mar 2016, Volume 2016, p.1 - 3
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Abstract
A combination of audiomagnetotelluric (AMT) surface and borehole measurements can be expected to reduce the ambiguity in models of electrical resistivity derived from surface measurements. For a synthetic 2-D model with a dipping mineralisation zone of ~ 1 Ohmm resistivity and 1.5 km depth extent embedded in a resistive host of 10000 Ohmm underneath weathered overburden of 100 Ohmm, we present a comparison of 2-D inversion models derived from combinations of surface impedance measurements and borehole measurements in the form of vertical magnetic transfer functions and vertical electric transfer functions. We have observed that based on combinations of ground and borehole AMT measurements the resulting inversion models have better pronounced resistivity contrasts at depth than models computed exclusively from surface measurements. To use the borehole transfer functions suggested by us, 3-component borehole sensors sufficiently sensitive to the AMT magnetic field need to be developed. A miniaturised 3-component SQUID magnetometer seems to be a promising solution.