LITHOLOGIC, PETROLOGIC, AND GEOCHEMICAL INVESTIGATION OF THE LOWER LAKE VERMILION FORMATION
All these lithologies have been metamorphosed to greenschist-amphibole facies. Geochemical data (whole-rock geochemical analyses) support field interpretations and appear to indicate a series of juxtaposed volcanic-derived units that include both continental arc-derived felsic volcanic material, as well as basaltic material of oceanic arc origin. The geochemical data and petrologic observations also indicate several intrusive events that exhibit different chemical and mineral compositions. Based on field evidence from bedding within the felsic volcanics, the younging direction is to the south. Basaltic flows are most abundant to the north, and transition to felsic volcaniclastic rocks, which are more abundant in the south. These observations suggest that the lithologies mapped in this outcrop record tectonic juxtapositioning of packages of volcanic rocks that range from basaltic through to felsic, possibly capturing a snapshot of magma evolution over time.