Magnetotellurics and Airborne Electromagnetics - a combined method for assessing basin structure and exploring for unconformity-related uranium

Millicent Crowe; Graham Heinson; Tania Dhu

doi:10.1071/ASEG2013ab225

ISSN: 2202-0586
E-ISSN:

oa Magnetotellurics and Airborne Electromagnetics - a combined method for assessing basin structure and exploring for unconformity-related uranium
Authors Millicent Crowe^a, Graham Heinson^b and Tania Dhu^c
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^a School of Earth and Environmental SciencesUniversity of Adelaide, , Adelaide, SA, 5005, now at Geoscience Australia GPO Box 378 Canberra, ACT, 2601, [email protected] ^b School of Earth and Environmental SciencesUniversity of Adelaide, , Adelaide, SA, 5005, [email protected] ^c Geological Survey of South Australia, DMITRE, Adelaide, SA, now at Northern Territory Geological Survey GPO Box 4550, Darwin, NT, 0801, [email protected]
Publisher: Australian Society of Exploration Geophysicists
Source: ASEG Extended Abstracts, Volume 2013, Issue ASEG2013 - 23rd Geophysical Conference, Dec 2013, p. 1 - 5
DOI: https://doi.org/10.1071/ASEG2013ab225
- Published online: 01 Dec 2013

Abstract

Unconformity-type uranium deposits are high-grade and constitute over a third of the world’s uranium resources. The Cariewerloo Basin, South Australia, is a region of high prospectivity for unconformity-related uranium. An airborne electromagnetic (AEM) survey was flown in 2010 using the Fugro TEMPEST® system to delineate the unconformity surface at the base of the Pandurra Formation. However highly-conductive regolith attenuated the signal in the northern and eastern regions, requiring application of deeper geophysical methods. In 2012 a magnetotelluric (MT) survey was conducted along a 110 km transect of the north-south trending AEM line.

MT data were collected at 29 stations and successfully imaged the depth to basement, and additionally providing evidence for deeper fluid pathways. The AEM data were integrated into the regularisation mesh as a-priori information generating an AEM constrained resistivity model and also correcting for static shift. The AEM constrained resistivity model best resolved resistive structures, allowing strong contrast with conductive zones.

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References

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Article Type: Research Article

Keyword(s): airborne electromagnetic (AEM); Cariewerloo Basin; electromagnetic induction; Magnetotellurics (MT); unconformity; uranium

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oa Magnetotellurics and Airborne Electromagnetics - a combined method for assessing basin structure and exploring for unconformity-related uranium

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