The Narrows Project - Thunder Bay
Geology
The Narrows Property is located within the Shebandowan Greenstone Belt in the Wawa Sub-Province, an Archaean-aged package of mafic to intermediate volcanics, sediments and rare volcanoclastics that have been variably intruded by felsic (porphyritic) sills, dykes and stocks. Regional metamorphic grade is described as Lower Greenschist Facies with localized contact metamorphism around granitic intrusives reaching Amphibolite Facies. The dominant structural trend in east-west to northeast, with gold mineralisation showing a preferential northeasterly orientation.
A number of small to medium-sized (especially to the east of Thunder Bay) layered mafic-ultramafic intrusive Complexes are recorded within the Superior Province, some of which have been or are currently the focus of Platinum Group Elements exploration.
Within the Project area, the geology is described as an east-west trending sequence of volcanics and sediments. Volcanics are generally mafic to intermediate in composition, with a minor felsic component. Sediments include conglomerates, argillites, arkose and BIF/cherts. Within the areas to the north of the project, a thick sequence of greywacke overlies the sediment package.
Both mafic and felsic dykes are recorded within the area. Mafic dykes range in composition from gabbroic to perdiotitic, whilst felsic intrusives ranges from feldspar to quartz-feldpar porphyries.
In the southern portion of the Narrows Property, a small layered mafic-ultramafic intusive known as the Haines Intrusive Complex occurs. No mention of extensive deformation of the Complex is noted, although some faulting/shearing at the margins would be expected. The Haines Intrusive Complex represents one of a series of layered mafic-ultramafic intrusives within the Superior Province, several of which are highly prospective for Platinum Group Elements.
Approximately half of the Narrows Property is covered by Lake Shebandowan itself. Areas above the lake include low lying hills with some outcrop as well as marshy areas.
Target Models
Three styles of mineralisation are recognized within the Shebandowan Greenstone Belt.
They are:
- Stratigraphically-controlled (Volcanogenic Massive Sulphides-style, Copper- Zinc)
- Intrusion related (PGE mineralisation identified by IGC )
- Shear zone quartz vein hosted gold ('Main Zone', No.4 Zone, Shebandown Project, Band-Ore Resources Ltd).
Within the Narrows Property, the majority of gold occurrences identified to date are structurally related (shear zone ), with a spatial association with intrusive felsic porphyries (B and E Zones) or gabbros (Hi-grade Zone, Jimbob 1 & 2, Portage Zone ). Mineralisation consists of sulphidic quartz veins, generally with carbonate-chlorite alteration. However, to date, prospects discovered comprise thin (but sometimes high grade) or erratically mineralized quartz vein systems.