Nature and origin of copper-gold mineralization at the Minto and Williams Creek deposits, west-central Yukon: Preliminary investigations

A new research project was begun in 2002, aimed at better understanding the nature and origin of copper-gold mineralization and its main host rocks at the Minto and Williams Creek (Carmacks Copper) deposits in west-central Yukon. This will also help to further constrain exploration models both on a property and a regional scale. Field work in 2002 confirmed that the main host rocks for both deposits are variably deformed plutonic rocks (diorite and quartz diorite at Williams Creek and mainly granodiorite at Minto). Mineralization formed prior to the ductile deformation that has affected these units. Mineralized granodioritic gneiss from Minto and apparently post-mineralization quartz diorite at Williams Creek yield U-Pb ages of ~194 Ma and ~191 Ma, respectively; thus the mineralization appears to have formed at essentially the same time as the host intrusions. Reconnaissance Pb- and S-isotope analyses of sulphide minerals from both deposits also indicate a likely magmatic source for the mineralization.