Exploration under regolith cover, and the problem of remanent magnetism: an example from the Tanami Au province

Kate Pfeiffer; Nicholas G Direen; Mike Sexton

doi:10.1071/ASEG2006ab132

ISSN: 2202-0586
E-ISSN:

oa Exploration under regolith cover, and the problem of remanent magnetism: an example from the Tanami Au province
Authors Kate Pfeiffer^a, Nicholas G Direen^b and Mike Sexton^c
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^a Newmont Australia Ltd, 10 Richardson St West Perth, Perth, 6005, [email protected] ^b CRC-LEME School of Earth & Environmental Sciences, University of Adelaide, Mawson Laboratories, North Terrace Adelaide, , SA, , 5005, [email protected] ^c Consultant Geophysicist, 11 Ring Rd Alice River, , Qld, 4817, [email protected]
Publisher: Australian Society of Exploration Geophysicists
Source: ASEG Extended Abstracts, Volume 2006, Issue ASEG2006 - 18th Geophysical Conference, Dec 2006, p. 1 - 4
DOI: https://doi.org/10.1071/ASEG2006ab132
- Published online: 01 Dec 2006

Abstract

Evidence of remanent magnetism was observed in aeromagnetic images from The Granites/Tanami Inlier in the Northern Territory. An investigation was undertaken to verify whether remanent magnetism existed, and if so, what mineral and/or system caused it.

Alternating field demagnetisation and Curie Temperature analyses was employed to calculate the magnetic properties of whole rocks. Optical petrology and electron microscopy were then used to determine the minerals present and their chemical compositions.

The two dominant magnetic minerals in this region are multidomain magnetite and monoclinic pyrrhotite, confirmed by petrological analysis. Chemical analysis determined the magnetite and pyrrhotite were pure with no substitution of elements. Alternating field demagnetisation and Curie Temperature analyses show monoclinic pyrrhotite holds the remanent magnetism, but has a low magnetic susceptibility.

The study indicates there is remanent magnetism in the Tanami region. If there is inadequate understanding of magnetic data, misinterpretation of magnetic anomalies could occur.

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2026-01-18

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References

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Article Type: Research Article

Keyword(s): AF demagnetisation; Curie Temperature; magnetite; pyrrhotite; Tanami

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oa Exploration under regolith cover, and the problem of remanent magnetism: an example from the Tanami Au province

Abstract

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