The Greenstone Gold Property is located in an Archean-aged greenstone belt known as the Wabigoon Sub-province of the Superior Structural Province that contains several narrow, east-west striking sequences of volcanic and sedimentary rock. The southern edges of these sequences are spatially related to structural discontinuities thought to be thrust faults that have imbricated the sedimentary sequences. Locally, the dominant rock types are clastic sediments, oxide facies banded iron formation (BIF), felsic intrusives and mafic volcanics. Collectively, these rocks comprise the Beardmore-Geraldton Greenstone Belt.
Economic concentrations of gold at Greenstone are typical of Archean epigenetic hydrothermal gold deposits normally considered to be mesothermal lode gold deposits. The gold mineralization is primarily located in areas of high strain and deformation, with brittle structures providing a fluid pathway that can also host mineralization as veins or replacement zones associated with alteration.
At Hardrock, the majority of gold resides within BIF, porphyry and clastic sedimentary rocks proximal to the regional Bankfield – Tombill fault. The fault is a variably deformed, largely ductile high strain zone characterized by strong heterogeneous penetrative strain, narrow shear zones and breccia zones cutting a variety of protoliths. At Brookbank, the 6.5 kilometre long Brookbank shear zone hosts the Brookbank, Cherbourg and Foxear deposits. These deposits occur at the contact between mafic flows and polymictic conglomerate.