Brodie Stroh

Paragenetic Relationships and Timing of Mineralization of Gold-Bearing Quartz Veins, Western Yukon

Part of the Tintina Gold Province, Western Yukon is host to many economical mineral deposits of various styles. Specifically, the Klondike is one of the world’s richest and most productive placer gold districts, with over 20 million ounces recovered. Efforts made to determine and analyze the lode sources of these placer deposits has lead to the discovery of a widespread episode of orogenic gold mineralization in the Middle to Late Jurassic within the Klondike and other nearby mineral districts in the Yukon Tanana terrane. A general understanding of the orogenic vein distribution, structural control, and correlation with regional cooling ages has been established. However, the occurrences remain ambiguous in terms of their detailed timing of veining/mineralization relative to deformation and genesis. Additionally, no knowledge exists on how gold was introduced into the veins and if U-Th-Pb geochronometers can reliably determine an absolute age of the mineralizing event(s). Through detailed petrographic and analytical analysis, this study will establish controls on vein/alteration paragenetic relationships and gold mineralization. Wherever possible, the absolute age(s) of mineralization will be determined by U-Th-Pb dating of hydrothermal monazite.

Three mineral districts of economic interest will be considered:

1. Klondike district
2. Sixtymile district
3. White Gold district

The objectives for the study are:

1. Establish controls on vein/alteration paragenetic relationships and gold mineralization
2. Determine the composition of the fluid(s) responsible for vein formation and mineralization
3. Define the temporal framework for mineralization
4. Interpret the results to define similarities/differences at various scales, including district wide, within Western Yukon, regionally, and the global orogenic gold model