The Fenelon property is largely underlain by NW-SE trending sedimentary and lesser mafic volcanic rocks of the Manthet domain north of the Sunday Lake deformation zone. These rocks have been intruded by intermediate to mafic/ultramafic sills and lesser dykes. Structural zones developed within or along the margins of these intrusive rocks have served as the most common focal points for gold accumulation.
To the east, at deeper stratigraphic levels, this sequence is underlain by the Grasset Ultramafic Complex which features interlayered ultramafic and felsic volcanic rocks which are intruded by cumulate ultramafic sills and dykes. Both Type-1 and Type-2 komatiite-hosted nickel sulphide mineralization occurs within the Grasset Ultramafic Complex as does generally pyrite rich, volcanic-hosted massive sulphide mineralization within the felsic members of the Complex.
To the north the sequence is intruded by the Jeremie Pluton: an ovoid shaped, composite (diorite-monzodiorite-granodiorite) intrusive body.
South of the Sunday Lake deformation zone the stratigraphy is dominated by east-west trending sedimentary rocks of the Matagami domain. Timiskaming-type polylithic conglomerates are observed within this sequence proximal to and within the SLDZ. To date no significant mineralization has been identified within this sequence south of the SLDZ, however exploration of part of the property is extremely limited.
Gold mineralization within the Fenelon area is generally found in narrow quartz-chlorite-chalcopyrite veins. Visible gold mineralization is not uncommon, and where present leads to grades across narrow widths which can commonly exceed 20 g/t gold. Veining can occur in a variety of host lithologies, but is concentrated in mafic to ultramafic sills and dykes on the Fenelon Mine property with the surrounding sedimentary lithologies proving to be much less receptive hosts. Recent discoveries along the Area 51 corridor are thus far very poorly described, but are present in both intermediate intrusive and volcanic hosts with lower-grade mineralization locally extending out into the sedimentary sequence.