Re-Os dating of gold in gold-bearing orogenic vein systems in the Klondike district – progress report

This is a preliminary study to determine the feasibility of using Re-Os to determine the age of gold in orogenic vein gold of the Klondike district, Yukon. Our objectives were to measure gold from several different vein systems to determine if enough Re and Os exists in native gold samples from the Klondike district to properly date the system. Six samples from different veins contain measurable concentrations of Re and Os and plot with significant variation on a Re-Os isochron diagram. The results indicate the need for detailed sampling of one vein system to better constrain age and source information from Re-Os systematics. Analysis of both native gold and synchronous pyrite from veins may provide enough data to determine age contraints, if native gold is not available.