Mineral potential modelling of gold and silver mineralization in the Nevada Great Basin — A GIS-based analysis using weights of evidence

Open-File Report 2001-291
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Abstract

The distribution of 2,690 gold-silver-bearing occurrences in the Nevada Great Basin was examined in terms of spatial association with various geological phenomena. Analysis of these relationships, using GIS and weights of evidence modelling techniques, has predicted areas of high mineral potential where little or no mining activity exists. Mineral potential maps for sedimentary ("disseminated") and volcanic ("epithermal") rock-hosted gold-silver mineralization revealed two distinct patterns that highlight two sets of crustal-scale geologic features that likely control the regional distribution of these deposit types.

The weights of evidence method is a probability-based technique for mapping mineral potential using the spatial distribution of known mineral occurrences. Mineral potential maps predicting the distribution of gold-silver-bearing occurrences were generated from structural, geochemical, geomagnetic, gravimetric, lithologic, and lithotectonic-related deposit-indicator factors. The maps successfully predicted nearly 70% of the total number of known occurrences, including ~83% of sedimentary and ~60% of volcanic rock-hosted types. Sedimentary and volcanic rockhosted mineral potential maps showed high spatial correlation (an area cross-tabulation agreement of 85% and 73%, respectively) with expert-delineated mineral permissive tracts. In blind tests, the sedimentary and volcanic rock-hosted mineral potential maps predicted 10 out of 12 and 5 out of 5 occurrences, respectively. The key mineral predictor factors, in order of importance, were determined to be: geology (including lithology, structure, and lithotectonic terrane), geochemistry (indication of alteration), and geophysics.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Mineral potential modelling of gold and silver mineralization in the Nevada Great Basin — A GIS-based analysis using weights of evidence
Series title Open-File Report
Series number 2001-291
DOI 10.3133/ofr01291
Year Published 2001
Language English
Publisher U.S. Geological Survey
Description 448 p.
Country United States
State Nevada
Other Geospatial Great Basin
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