Authors / CoAuthors
Jiang, W. | Duan, J. | Schofield, A. | Brodie, R.C. | Clark, A.
Abstract
Geoscience Australia has undertaken a series of integrated studies to identify prospective regions of mineral potential using new geological, geophysical and geochemical data from the Exploring for the Future (EFTF) program, together with legacy datasets. The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a collaborative national survey, which aims to acquire long-period magnetotelluric (MT) data on a half-degree grid spacing (~55 km) across the entire Australian continent. The resistivity model derived from the newly-acquired AusLAMP data has mapped deep lithospheric-scale conductivity anomalies in highly endowed mineralised regions and in greenfield regions where mineralisation was not previously recognised. For example, the model reveals a conductivity anomaly extending from the Tennant Region to the Murphy Province, representing a potential fertile source region for mineral systems. This conductive feature coincides with a broadly northeast-southwest-trending corridor marked by a series of large-scale structures identified from preliminary interpretation of seismic reflection and potential field data. This under-explored region, referred to as East Tennant, is, therefore, considered to have significant mineral potential. We undertook a higher-resolution magnetotellurics survey to investigate if the deep conductivity anomaly is linked to the near surface by crustal-scale fluid pathways. Broadband MT (BBMT) and audio-MT (AMT) data were acquired at 131 stations with station spacing of ~2 km to ~15 km in an area of approximately 90 km x 100 km. The 3D resistivity model revealed two prominent conductors in the resistive host whose combined responses result in the lithospheric-scale conductivity anomaly mapped in the AusLAMP model. The resistivity contrasts coincide with major structures preliminarily interpreted from seismic reflection and potential field data. Most importantly, the conductive structures extend from the lower crust to the near surface. This observation strongly suggests that the major faults in this region are deep-penetrating structures that potentially acted as pathways for transporting metalliferous fluids to the upper crust where they could form mineral deposits. This result indicates high mineral prospectivity for iron oxide copper–gold deposits in the vicinity of these major faults. We then used AMT data to constrain cover thickness to select targets at drillable depths for the stratigraphic drilling program which, in turn, will test the models and improve our understanding of basement geology, cover sequences and mineral potential. This study demonstrates that integration of geophysical data from multiscale surveys is an effective approach to scale reduction during mineral exploration in covered terranes with limited geological knowledge. This Abstract was submitted/presented to the 2021 Australasian Exploration Geoscience Conference 13 - 17 September https://2021.aegc.com.au/.
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144382
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- EARTH SCIENCES
- ( Discipline )
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- magnetotellurics
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- Exploring for the Future
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2023-02-17T01:28:51
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Abstract to be presented the Australasian Exploration Geoscience Conference Brisbane 2021 - https://2021.aegc.com.au/
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Australasian Exploration Geoscience Conference 13-17 September 2021 Brisbane QLD
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Abstract presented the Australasian Exploration Geoscience Conference Brisbane 2021 - https://2021.aegc.com.au/
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[-44.00, -9.00, 112.00, 154.00]
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