Controls on gold distribution at the Horne 5 VMS deposit, Abitibi greenstone belt, Quebec

The gold-bearing Home 5 VMS deposit is located in the Blake River Group of the Abitibi greenstone belt. Hosted within steeply-dipping, north-facing felsic volcaniclastic units, the deposit is fault-bounded and within the boundaries of the Home block. Mineralization consists of a series of massive to semi-massive sulfide lenses alternating with disseminated and stringer sulfides in coarse felsic volcaniclastic units. The latter often contain massive sulfide clasts. Results from this study show: 1) alteration in the mineralized zones is of moderate intensity and consists of pervasive sericite quartz; 2) a well-developed foliation is present throughout most of the mineralized zone and is particularly prominent in sericitized zones; 3) sphalerite is associated with massive to disseminated pyrite, whereas chalcopyrite is locally remobilized in secondary sites within the mineralized intervals; 4) gold distribution is relatively variable, but higher gold contents are generally present in the massive to semi-massive sulfide intervals; and 5) less permeable strata within the host volcaniclastic units most likely influenced the distribution of the mineralization interpreted to have formed mostly by sub-seafloor replacement. The Horne 5 deposit represents an opportunity to better understand ore-forming processes in large Archean synvolcanic gold systems.