The Abitibi granite-greenstone belt has long been known for its’ world-class Archean
lode gold deposits. With exploration and production commencing in the early nineteen
hundreds and continuing into the twenty-first century, this prolific mining camp is rich
in history, research and precious/base metals. The Thunder Creek deposit and Hwy-144 gold prospect are two recently discovered and exploited syenite associated gold plays in the Timmins Camp. The research compares the Thunder Creek and Hwy-144 properties providing new observations on the variable mechanisms for gold mineralization that can change over a short strike distance (0.5-1.5 km’s) hosted in a geologically similar environment. While both properties show broad similarities like; syenite hosted mineralization and quartz vein + pyrite associated with mineralization; differences including alteration assemblages and pyrite geochemistry explain the disparity in mineralization intensity between the two properties. Disseminated pyrite mineralization at Thunder Creek is synchronous with gold mineralization. This style of mineralization is overprinted by the main stage of mineralization expressed by the formation of V1 and V2 quartz veins carrying the bulk of gold mineralization. Vein-formation occurred in response to D3 deformation in the adjacent Rusk Shear Zone, with silicification the main alteration assemblage. At Hwy-144, hematitic and potassic alteration vary in intensity and appear to be only loosely associated with gold mineralization. Pyrite geochemistry reveals that pyrite crystallized out of a gold-poor fluid. Gold mineralization is restricted primarily to vein-hosted pyrite grains with inclusions of gold likely deposited by late auriferous fluids that corroded pyrite grains
