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Lithologic mapping using Random Forests applied to geophysical and remote-sensing data: a demonstration study from the Eastern Goldfields of Australia

Citation

Kuhn, S and Cracknell, MJ and Reading, AM, Lithologic mapping using Random Forests applied to geophysical and remote-sensing data: a demonstration study from the Eastern Goldfields of Australia, Geophysics, 83, (4) pp. 183-193. ISSN 0016-8033 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 the Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1190/GEO2017-0590.1

Abstract

The Eastern Goldfields of Western Australia is one of the world’s premier gold-producing regions; however, large areas of prospective bedrock are under cover and lack detailed lithologic mapping. Away from the near-mine environment, exploration for new gold prospects requires mapping geology using the limited data available with robust estimates of uncertainty. We used the machine learning algorithm Random Forests (RF) to classify the lithology of an underexplored area adjacent to the historically significant Junction gold mine, using geophysical and remotesensing data, with no geochemical sampling available at this reconnaissance stage. Using a sparse training sample, 1.6% of the total ground area, we produce a refined lithologic map. The classification is stable, despite including parts of the study area with later intrusions and variable cover depth, and it preserves the stratigraphic units defined in the training data. We assess the uncertainty associated with this new RF classification using information entropy, identifying those areas of the refined map that are most likely to be incorrectly classified. We find that information entropy correlates well with inaccuracy, providing a mechanism for explorers to direct future expenditure toward areas most likely to be incorrectly mapped or geologically complex. We conclude that the method can be an effective additional tool available to geoscientists in a greenfield, orogenic gold setting when confronted with limited data. We determine that the method could be used either to substantially improve an existing map, or produce a new map, taking sparse observations as a starting point. It can be implemented in similar situations (with limited outcrop information and no geochemical data) as an objective, data-driven alternative to conventional interpretation with the additional value of quantifying uncertainty.

Item Details

Item Type:Refereed Article
Keywords:random forests, orogenic gold, mineral exploration, geological mapping
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geophysics not elsewhere classified
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Precious (Noble) Metal Ore Exploration
UTAS Author:Kuhn, S (Mr Stephen Kuhn)
UTAS Author:Cracknell, MJ (Dr Matthew Cracknell)
UTAS Author:Reading, AM (Professor Anya Reading)
ID Code:126310
Year Published:2018
Web of Science® Times Cited:6
Deposited By:CODES ARC
Deposited On:2018-06-05
Last Modified:2019-03-13
Downloads:57 View Download Statistics

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