Mapping Hydrothermal Alteration Zones at a Sediment-Hosted Gold Deposit - Goldstrike Mining District, Utah, Using Ground-Based Hyperspectral Imaging
Abstract
Understanding the origin, genesis, as well as depositional and structural mechanisms of gold mineralization as well as detailed mapping of gold-bearing mineral phases at centimeter scale can be useful for exploration. This work was conducted in the Goldstrike mining district near St. George, UT, a structurally complex region which contains Carlin-style disseminated gold deposits in permeable sedimentary layers near high-angle fault zones. These fault zones are likely a conduit for gold-bearing hydrothermal fluids, are silicified, and are frequently gold-bearing. Alteration patterns are complex, difficult to distinguish visually, composed of several phases, and vary significantly over centimeter to meter scale distances. This makes identifying and quantifying the extent of the target zones costly, time consuming, and discontinuous with traditional geochemical methods. A ground-based hyperspectral scanning system with sensors collecting data in the Visible Near Infrared (VNIR) and Short-Wave Infrared (SWIR) portions of the electromagnetic spectrum are utilized for close-range outcrop scanning. Scans were taken of vertical exposures of both gold-bearing and barren silicified rocks (jasperoids), with the intent to produce images which delineate and quantify the extent of each phase of alteration, in combination with discrete geochemical data. This ongoing study produces mineralogical maps of surface minerals at centimeter scale, with the intent of mapping original and alteration minerals. This efficient method of outcrop characterization increases our understanding of fluid flow and alteration of economic deposits.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.V51F0429K
- Keywords:
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- 1099 General or miscellaneous;
- GEOCHEMISTRY;
- 3699 General or miscellaneous;
- MINERALOGY AND PETROLOGY;
- 8499 General or miscellaneous;
- VOLCANOLOGY