In the southeast Yukon, immediately southwest of the mid-Cretaceous Cassiar suite plutons,is a northwest-trending suite of anorogenic one-mica granites called the Seagull suite. This suite is comprised of the Seagull and Hake batholiths, Ork and Thirtymile stocks and an un-named intrusion to the northwest. These B and F enriched granites are associated with various forms of tin mineralization, including skarns. The Mindy prospect in the Thirtymile Range contains a variety of metasomatic silicate and borate and fluoride minerals. Tin (Sn) mineralization is found as cassiterite and borate mineral phases. Mapping has shown that faulting active during metamorphism-metsomatism controlled the distribution of the skarn mineralization. Both mineral chemistry and structural control of mineralization have a significant effect on the economic potential of the Mindy prospect.
