Summary:
Deposit Types
The Tower Gold deposits can be classified as structurally controlled orogenic gold deposits in an Archean greenstone belt setting. The Abitibi greenstone belt of Ontario and Quebec is located in the southeastern portion of the Superior Province (Nassif et al., 2018) of the Canadian Shield. This deposit type is a significant source of gold mined in the Superior and Slave provinces. These deposits are typically quartz vein hosted and are distributed along crustal-scale fault zones that mark convergent margins between major lithological boundaries such as those between volcano-plutonic and sedimentary domains. The Tower Gold Project is located on the Destor-Porcupine fault zone (DPFZ), a major auriferous regional structure. Several geological styles of deposits can be distinguished:
• Quartz-carbonate veins in shear zones, faults, and folds, and related extensional structures.
• Zones of stockwork veinlets and disseminated sulphides associated with small porphyry intrusions.
• Sulphide-rich veins and vein arrays.
Rare carbonate-rich veins and siliceous replacements.
The DPFZ in northeastern Ontario hosts the largest Archean orogenic gold camp in the world and has produced over 75 Moz of gold from the Timmins Camp alone. When combined with the adjacent Larder Lake-Cadillac Fault Zone and associated splays, this region has hosted over 200 Moz of gold (Dubé, B et al. 2017). Along the DPFZ the main host rocks are greenschist facies metamorphic rocks of dominantly mafic to ultramafic metavolcanic rocks intruded by intermediate to felsic porphyry. In the Timmins area, larger deposits are spatially associated with fluvio-alluvial conglomerate (Timiskaming conglomerate) distributed along major and deep-seated crustal fault zones such as the DPFZ. On the Tower Gold Project, a banded iron formation transects the Timiskaming sedimentary basin and is spatially associated with gold mineralization.
The deposits are typically associated with iron-carbonate (ankerite) and sericite alteration with gold usually occurring in the quartz-pyrite vein network. Significant gold can also occur associated with the iron-rich, sulphidized, wall rock selvages or within silicified and pyrite-rich replacement zones.
Gold Mineralization
Golden Highway Mineralization Mineralization within the Golden Highway Project area is dominantly hosted within the Timiskaming sediments. From west to east, the deposits of interest are: 55, Westaway, Southwest, Windjammer Central and Windjammer South. Mineralization is also hosted in sheared volcanics of the Tisdale assemblage north of the Timiskaming, the most notable being the Windjammer North deposit.
Timiskaming Hosted Mineralization
Mineralized zones within the Timiskaming occur adjacent to and south of a BIF horizon and are hosted within greywacke and argillite. There is also a close association between mineralization and the presence of felsic intrusives. Mineralization broadly follows stratigraphy and occurs up to 200 m south of the BIF. This trend also exhibits shearing parallel to stratigraphy, the intensity of which decreases from west to east. Shearing may occur in broad zones south of the BIF like in 55 or be partitioned into discrete horizons < 2 m wide (e.g. Westaway). Kinematics of shearing is uncertain and represent either early Destor-Porcupine thrust surfaces and/or strike slip deformation.
Gold occurs in association with quartz veining, disseminated pyrite, and ankerite alteration. There are at least three (3) styles of quartz veining associated with mineralization: laminated fault fill veins, quartz vein breccia and stockwork veining. Quartz vein breccias (QVBs) are the youngest generation, as they crosscut fault fill veins in 55. QVBs range in width from 10 cm to 3 m, have a glassy appearance, and contain angular clasts of wall rock material up to 5 cm in size. Stockwork veining is interpreted as being contemporaneous with quartz vein breccias (QVBs) as they have a similar appearance and occur in proximity to QVBs. Individual stockwork veins are < 5 cm wide. Early fault fill veins contain dark grey laminations and are generally narrower than QVBs (< 30 cm). There is little to no replacement style mineralization surrounding fault fill veins, unlike QVBs and stockwork which are associated with replacement and vein hosted gold mineralization.
Tisdale Hosted Mineralization
North of, and parallel to the Timiskaming basin, is a series of deposits hosted within sheared Tisdale ultramafic and mafic volcanics. From east to west the zones and deposits are Twin Creeks, Landing, Discovery and Windjammer North. They occur within a 150 m wide zone of sheared ultramafic volcanics with lenses of basalt and felsic intrusives. It is unknown whether these felsic dykes are older or the same age as those intruding the Timiskaming sediments. The shear zone, characterized by talcose ultramafics, is interpreted as a branch of the Destor-Porcupine fault zone, however it could potentially be similar in age to the Pipestone fault. Potassic alteration broadly defines a halo to mineralized zones, either as bright green fuchsite in ultramafic volcanics or yellow sericite alteration in basalt.
The deposits within the Tisdale, were modelled by defining mineralized envelopes, closely associated with altered and sheared units. The new mineralization model is composed of 102 sub-vertical mineralized envelopes with an east-northeast strike with an average thickness of approximately 2.4 m.
Garrison Mineralization
There are two (2) main deposit styles within the Garrison Project area. Both the 903 and Jonpol deposit mineralization is hosted within sheared volcanics closely associated with felsic intrusions, whereas the Garrcon deposit is sediment hosted mineralization.
Volcanic Hosted Mineralization
The 903 and Jonpol deposits are hosted in structurally controlled alteration zones within mafic to ultramafic (tholeiitic to komatiitic) rocks. In both deposits, gold mineralization is closely associated with felsic intrusive rocks. Alteration is characterized by pervasive carbonate with late stage silicification, sulphidization and sericitization.
The felsic magmatism occurred from 2,682 - 2,672.6 Ma (Nassif et al. 2024), contemporaneous with deposition of the Porcupine and Timiskaming assemblages and movement along the DPFZ. At the Jonpol and 903 deposits, gold mineralization is hosted in fractured, pyritic, and quartz vein-bearing syenite dykes. At Jonpol, gold mineralization is also hosted in albitite dykes. At both deposits, the intrusions associated with gold are sub-parallel to the shear foliation, dipping steeply to the south.
Sediment Hosted Mineralization
The Garrcon deposit comprises a broad zone of low-grade gold mineralization that includes local higher-grade areas hosted within the sedimentary basin. Although the sediments are not dated directly, they are inferred to be of Porcupine age (Nassif et al. 2024). This deposit is located north of and proximal to the DPFZ and exhibits a shallow eastward plunge.
The Garrcon deposit is characterized by brecciated, silicified metasediments with quartz-carbonate vein stockworks, less than 1% disseminated sulphides, and additional intrusions of altered lamprophyre and syenite dykes. Hydrothermal alteration has rendered distinct auriferous zones within the metasediments, which extend to depths exceeding 650 m vertically.
Other Gold Zones
In addition to the main resources of the Project, the Tower Gold property currently hosts multiple distinct gold-bearing zones (including Landing, Twin Creeks, LC, Dyment3, and Western from east to west) in the Michaud Township. At present, there is insufficient drilling in the zone areas to complete an interpretation and resource estimate on them. The property has a total of 53 showings and occurrences at various developmental stages.