Petrology and Geochemistry of Quartz-Tourmaline Vein Alteration of a Granodiorite, Heyson Township, Red Lake, Ontario

Abstract

<p> The Buffalo Mine, located in Heyson Township, Red Lake, consists of quartz-tourmaline veins in a grandiorite. An alteration halo, consisting of andesine feldspar, quartz, calcite, with minor tourmaline, zircon, and opaques, is seen surrounding the veins. Opaque minerals consists of pyrite and hematite. Possible Na - overgrowths of the Plagioclase are seen , as well as complete destruction of the mafic minerals. </p> <p> Geochemistry shows that the wall-rock alteration involves the breakdown of Si, Al, Fe, Mg, Na, and K . Si and Al remain fairly constant, while Na and Ca increase and Fe, Mg, and K decrease in abundance. There has been a sufficient input of CO2 to precipitate calcite, as well as Enough sulfur to form pyrite. </p> <p> The initial hydrothermal solutions were high temperature NaCl solutions, enriched in boron and containing some CO2 . The fluids were likely oxidizing and had a neutral pH. </p>