Liam Fay Honours Thesis Abstract

Thesis Title: 
Mineral Chemistry of the Heron Bay Area, Northwestern Ontario

Heron Bay, Ontario comprises a predominantly calc-alkaline felsic to intermediate subduction-related arc setting of volcanic and plutonic rocks of mostly crystal tuff, tuff and granite. The rocks have undergone amphibolite facies metamorphism and are predominantly schists and gneisses. Trace element concentrations in pyrite, chlorite and epidote are variable. Highest values of Archean Au pathfinder elements, Au, Sb, W, Bi and As in pyrite are observed in pyrite associated with tourmaline in veins and disseminations. Highest concentrations of Au, Sb, W, Bi and As in chlorite and epidote are generally  associated with chlorite and epidote that occurs in veins rather than as major to minor constituents of rocks or as replacements. Trace element abundances in pyrite, chlorite and epidote are similar to Hemlo, the La Colosa Au-porphyry deposit and Gosowong, Toguraci and Penelope epithermal deposit pyrite, chlorite and epidote. Heron Bay chlorite is similar to metamorphic chlorite from Shebandowan and West Scotland and Heron Bay epidote is similar to metamorphic epidote from West Scotland.

No strong trace element trends towards the Heron Bay Au mine are apparent. The lack of strong vectoring trends may be attributed to metamorphic overprint, the small size of the Heron Bay Au system and variability in trace element concentrations among the differing occurrences of pyrite, chlorite and epidote.