Summary:
The Island Gold Property is located in the Michipicoten Greenstone Belt (“MGB”) which is part of the Wawa Subprovince within the Archaean Superior Province.
The Island Gold Mine is an Archean orogenic lode gold deposit. The host terrane is a sequence of felsic to intermediate volcanic rocks of the Wawa Assemblage which are in the greenschist metamorphic range as is common for this type of deposit. High strain zones associated with the GLDZ have the tendency to develop at variable scales along lithologic unit contacts where complex geology and related competency contrasts can control stress patterns and facilitate shearing and the consequent development of dilatancy zones and concomitant quartz carbonate vein formation. It is generally accepted that these Archean orogenic lode gold deposits are related to compressional and transpressional tectonics and the associated metamorphic dewatering and devolatization of magma processes from which the gold-bearing fluids are derived.
A major regional deformation zone called the Goudreau Lake Deformation Zone (“GLDZ”) is situated throughout the area. It is a north-easterly trending structure that has been traced along strike for 30 km with a width of 4.5 km and is believed to be the main control of gold mineralization for the Project area. It is a high-angle oblique-slip fault zone with an overall dextral movement cutting stratigraphy at a shallow angle. There are three main splays to the GLDZ in the area, the southernmost of which hosts the Island Gold Mine structure, which contains a stacked sequence of east-northeast striking, steeply dipping, and subparallel zones of gold mineralization.
The Island Gold Mine is stratigraphically positioned in the upper portion of the Wawa Assemblage on the northern limb of the Goudreau Anticline. This assemblage is mostly composed of felsic volcanic rocks of various facies of tuffs and lavas.
Quartz veins commonly bear visible gold in the form of aggregates, disseminated fine grains, or along chlorite-sericite slickensides within the veins. The degree of veining appears to change at depth, transitioning from a stringer style quartzcarbonate vein on scales between mm to larger-scale veins which can be over 4 m in width.
The Island Gold deposit is composed of multiple, stacked, south-dipping lenses. The mineralized corridor expands from 50 m wide in the upper levels to over 150 m wide at depth. The zone’s dip varies from sub-vertical to vertical from -50° to -90° south. Locally, north dip reversals occur but are not common. Rare instances of offset or folding have been seen. Around the 400 m levels, there is a shallow dipping southern inflection of the mineralized zones. It is not yet clear if this inflection is related to a fault, a shear zone, or a fold. This inflection point is the division of what is locally referred to as the Upper Island Gold Mine and the Lower Island Gold Mine.
The Island Gold Mine is an Archean orogenic lode gold deposit. It is a structurally hosted quartz-carbonate vein system situated within the Goudreau Lake Deformation Zone (“GLDZ”), a major regional brittle-ductile structure. The host terrane is a sequence of felsic to intermediate volcanic rocks of the Wawa Assemblage which are in the greenschist metamorphic range as is common for this type of deposit. High strain zones associated with the GLDZ have the tendency to develop at variable scales along lithologic unit contacts where complex geology and related competency contrasts can control stress patterns and facilitate shearing and the consequent development of dilatancy zones and concomitant quartz carbonate vein formation. It is generally accepted that these Archean orogenic lode gold deposits are related to compressional and transpressional tectonics and the associated metamorphic dewatering and devolatization of magma processes from which the gold bearing fluids are derived.
Gold mineralization in the Goudreau-Lochalsh area is not restricted to any rock type with the general exception of the late intruding north-west trending Matachewan diabase dykes which show no evidence of mineralization. Deposits may be hosted by one or several rock types, with past-producing mines and numerous other gold occurrences in the area exhibiting a close spatial association with felsic, intermediate, and even mafic intrusive rocks. East of the Island Gold Mine, in Jacobson Township, the past producing Edwards and Cline Lake gold mines are associated with felsic intrusive complexes and dykes. The past producing Magino Mine to the immediate west of the Island Gold property is hosted by the Webb Lake stock, a trondhjemite intrusive. The past producing Kremzar Mine, located on the Island Gold property, is hosted by a regional gabbroic sill.
Mineralization in the Goudreau Camp occurs along a 30 kilometre strike length of the GLDZ which transects the Island Gold property area in a roughly east-west direction. The GLDZ is a major regional deformation structure and it is believed to be the main control on gold mineralization for the area. The GLDZ and subsidiary splays have been subdivided into four structural domains (Southern, Northern, Eastern and Western) based on the style of deformation, lineation patterns, and the orientation and sense of shear displacement on sets of shear zones. The Island Gold mine mineralized zones are within the Southern domain of the GLDZ (Heather and Arias 1992). Most mineralization in this domain is hosted by quartz veining and/or shear zones with an orientation of 075°. The zones with this orientation are roughly parallel with the overall deformation zone and are considered to have formed along shear planes related to the dextral oblique slip movement of the GLDZ.
Typical alteration mineralogy associated with gold deposits of the Goudreau Camp includes variable amounts of carbonatization (Fe-carbonate ± calcite), silicification, sulphidization, biotitization, sericitization, feldspathization, and chloritization. Deposits and gold occurrences with a felsic rock association are generally associated with a quartz-sericite-pyrite ± pyrrhotite alteration package. Deposits and occurrences hosted by mafic host rocks, such as the Kremzar Mine and the historic showings along this trend are generally altered to biotite, Fe-carbonate, pyrrhotite ± pyrite, quartz, and minor K-feldspar. Chloritization is common throughout the belt. Gold presence in the Goudreau-Lochalsh area is primarily associated quartz stringers, fracture fillings and veins. Gold can be associated with pyrite disseminated in alteration envelopes but generally only in low grade levels.