Maddison Hodder HBSc thesis abstract

Thesis Title: 
A mineralogical and geochemical study of granitoids from the Northern Revell Batholith, Ignace, Ontario

The Revell Batholith is located in the Western Wabigoon subprovince, near Ignace, Ontario. The batholith was emplaced at 2737 Ma and intrudes the Bending Lake greenstone belt. The purpose of this study was to mineralogically and geochemically classify the Revell North granitoid rocks and provide insight into the petrogenesis of the Revell Batholith.

The Revell North granitoid rocks were identified as three mineralogically distinct lithologies: 1) quartz-rich granitoid (that typically consists of a higher quartz content than the rest of the samples with a groundmass of fine-grained plagioclase feldspar, potassium feldspar and quartz); 2) granodiorite (composed of medium-grained quartz and feldspar phenocrysts with a groundmass of medium-fine grained quartz and plagioclase with minor sericite alteration); 3) monzogranite (consisting of medium-fine grained quartz making up the matrix with medium-fine grained plagioclase with a higher modal abundance of potassium feldspar). Three types of alteration are present in the Revell North: chlorite, epidote and sericite. Both chlorite and epidote alteration are minor, however, sericite alteration is present throughout the Revell North.

The Revell North granitoid rocks display a homogeneous calc-alkaline signature, showing minimal geochemical changes between lithologies. The Revell North is a calc-alkaline granite that is classified as an I-type granitoid with slight S-type characteristics. The Revell North granitoid rocks are considered to be pre-tectonic as the ages that are associated with the Revell are contemporaneous with volcanism in the Western Wabigoon Subprovince, and elsewhere for granitoid rocks of the Superior province. The emplacement of the Revell Batholith is suggested to be via multiple injections from a single magmatic source. The Revell North granitoids underwent fractional crystallization, creating some subtle mineralogical lithologies with little to no geochemical differences.