On the significance of aqueous fluid inclusions in gold-bearing quartz vein deposits from the southeastern Abitibi Subprovince (Quebec, Canada)
|Category||Economic geology & mineral exploration|
|Location||proceeding of economic geology journal 1997-2007|
|Holding Date||26 April 2008|
Fluid inclusions have been studied in a quartz-epidote-actinolite vein within a Proterozoic diabase dike crosscutting the Donalda 1 gold-bearing quartz vein, near Noranda, Quebec. Two types of fluid inclusions were recognized. The first type is represented by two-phase aqueous fluid inclusions characterized by low eutectic (<-45 degrees C), variable ice-melting (-33 to -6 degrees C), and high homogenization to the liquid phase (T (sub hL-v(L)) >200DGC) temperatures. The second type is represented by two- or three-phase (+ or - solid) aqueous fluid inclusions characterized by low eutectic (<-45 degrees C), highly variable ice-melting (-52.8 to -2.4 degrees C), low homogenization to the liquid phase (T (sub hL-v(L)) <130 degrees C, and halite dissolution (<200 degrees C) temperatures. This second fluid inclusion type is also described with H 2 O-CO 2 and CO 2 fluid inclusions in Archean gold-bearing quartz veins of the southeastern Abitibi belt and has a chemical composition (Ca-Na-Cl-bearing with variable salinity) comparable to that of brines and ground waters found in the Superior province. This study demonstrates that these low T h aqueous fluids showing variable salinity are unrelated to gold deposition, but should rather be correlated with younger brines and ground waters which percolated downward in the continental crust. In these gold-bearing quartz veins, only the high T h aqueous fluids may be linked to gold-bearing fluids.