Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Geology

Supervisor

Banerjee, Neil R.

2nd Supervisor

Van Loon, Lisa L.

Abstract

The Vertigo target on the southwestern JP Ross property is a gold-mineralized showing ~70 km south of Dawson City in the White Gold district, west-central Yukon Territory, Canada. Favourable gold-mineralized zones occur with pathfinder elements As-Ag-Te-Pb-Bi. This study uses digital borehole logging, petrography, electron probe microanalysis, and micro-x-ray fluorescence to evaluate the spatial, geochemical, and mineralogical distribution of Au mineralization at the Vertigo target. Petrographic and structural interpretations are contextualized with synchrotron radiation x-ray diffraction on 120 drill sample pulps. The clustering of diffraction patterns has revealed characteristic signatures of Au-mineralization with structural geometries coincident with the mineralogical clusters. The western Yukon and eastern Alaska experienced a protracted history of fault emplacement and mineralizing events with structural geometries prone to reactivation. The spatial distribution of mineralogical domains obtained from our objective cluster analysis provides compelling evidence for polyphase Au-mineralization at the Vertigo target.

Summary for Lay Audience

The Vertigo target is a gold mineralized hard-rock showing located ~70 km south of Dawson City in Canada's west-central Yukon Territory. The Yukon is best known for its prolific placer production of gold nuggets found in rivers and historic creek beds since the Klondike Gold Rush of 1897-1899. The quest for locating a hard-rock source of this placer endowment has since spurred exploration efforts in the region. The Vertigo target is one such showing where gold occurs in quartz veins near placer creek beds. The western Yukon and eastern Alaska experienced a long-lived history of mineralizing events. In areas with favourable spatial relationships and structural geometries, mineralizing fluids precipitated precious metals of value (e.g., Au) that solidified in the rock. Gold at the Vertigo target occurs with other elements that include As-Ag-Te-Pb-Bi. These are known as “pathfinder elements,” and this combination is unique with respect to orogenic showings in the district. This study uses multiple analytical techniques on samples taken from drill core at the Vertigo target, including x-ray diffraction to interpret sample mineralogy, x-ray fluorescence, and electron probe microanalyses to interpret sample geochemistry, and petrography to interpret sample mineralogy and structural relationships. Together, these techniques provide context for the anomalous geochemistry and insight into the relative timing of Au mineralization. Interpretation of optical televiewer imagery taken inside of drill holes has revealed structural geometries. A total of 120 samples taken from diamond drill intervals were selected for x-ray diffraction mineralogical work. These samples were then sorted into groups based on the degree of similarity between mineral readings (e.g., samples with similar mineralogy were clustered together). This analysis is largely objective as it distinguishes samples based on mineral domains. Mineralogical domaining, supplemented by petrography, x-ray fluorescence, and structural interpretation, identifies two primary domains and provides convincing evidence that Au-mineralization at the Vertigo target occurred in multiple stages.

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