Characterization and significance of lithogeochemical, stable isotope and mineral alteration halos in the Hollinger-McIntyre gold deposit, Timmins Ontario, Canada

Two distinct mineralizing fluids formed the Hollinger-McIntyre-Coniaurum deposit. The earliest fluid formed the disseminated Cu-Au-Mo zone in the Pearl Lake Porphyry (PLP). The alteration pattern in the felsic rocks of the PLP is characterized by increased amounts of K2O, Au, Cu, Mo, W, Sn, K/Al, Sericite/Chlorite Index (SCI) and Sericite Alteration Index and the removal of CaO. The H2O-CO2-NaCl mineralizing fluid involved had a temperature of 342 to 389°C and a delta18O water composition of 11.68 to 12.68‰.;The H2O-CH4-CO2-NaCl mineralizing fluid that formed the gold deposits associated with the Hollinger Shear Zone (HSZ) during northwest-southeast compression had an estimated temperature of 290°C and a delta18Owater 4.60‰. These auriferous fluids are associated with increases in As, CO2, and CO2/CaO and removal of Na2O from rocks in and above the HSZ. They are isotopically similar to those that formed the Giant and Colomac gold deposits.;A third alteration type is present and has added Na2O to the metavolcanic rocks. The addition of Na2O probably occurred during spilitic alteration of volcanic rocks when they were deposited in a subaqueous marine environment.