Geological Survey of Canada, Current Research (Online) no. 2002-C27

Book excerpt: This paper reports on a part of the study of the Goldcorp high-grade zone at the Red Lake gold mine, northern Ontario that carried out fluid inclusion microthermometric analyses on a few key samples representing different stages of gold mineralization. The purpose of the study is to provide an initial idea regarding the fluid characteristics before, during, & after the gold mineralization in order to better understand how the deposit was formed and to contribute to the ongoing debate on its genesis. Fluid inclusions were studied from three different mineral phases: pre-ore carbonate, syn-ore quartz, and post-ore euhedral quartz & associated carbonate. The paper reviews the regional & local geologic setting, the petrography of the samples studied, and the study methods employed, and interprets the microthermometric data with discussion of fluid immiscibility, temperature-pressure conditions of carbonate vein formation & silicification, temperature-pressure conditions of euhedral quartz formation, and the evolution of fluid composition.