Transient electromagnetic profiles across gold-mineralisation zones in central Victoria |
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| Authors: | Z R Dennis J P Cull R A Cayley |
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| Institution: | 1. School of Geoscience, Monash University , Vic, 3800, Australia zara.dennis@sci.monash.edu.au;3. School of Geoscience, Monash University , Vic, 3800, Australia;4. GeoScience Victoria, Department of Primary Industries , Vic, 3001, Australia |
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| Abstract: | High-density transient electromagnetic (TEM) profiles have been obtained along a 170 km long transect in central Victoria north of Bendigo. The transect lies within two of the fault-bounded subdivisions of the western Lachlan Fold Belt (the Bendigo and Melbourne Zones) and coincides with part of a 2006 seismic-reflection traverse and a 2007 magnetotelluric (MT) survey commissioned by Geoscience Victoria as part of the Victorian Government's Gold Undercover initiative. In addition to providing near-surface information that will assist with geological mapping, the TEM survey also presents a viable method for the removal of static offsets present in the MT data. The new dataset also provides an immediate comparison and verification of data acquired along the same line by the helicopter-borne Versatile Transient Electromagnetic (VTEM) system. Ground-based data have been obtained for a total of 55 sites, and high-quality decay curves have revealed a variety of conductivity characteristics with typical penetration to depths of 100 m. Major geological structures can clearly be identified in both the ground and airborne sections, with very good lateral correlation present between the two. The fault zones are easily distinguished as regions characterised by bands of high conductivity along with significant variability in the near-surface structure. |
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| Keywords: | Bendigo Zone gold Lachlan Fold Belt Melbourne Zone resistivity static offsets transient electromagnetic |
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