Volcanic stratigraphy and structural geology of the area of the Boston gold deposit, Hope Bay volcanic belt, Nunavut

The Boston gold deposit, located in the southern portion of the Hope Bay volcanic belt, is the largest known gold deposit in the belt. Rock types in the area of the deposit are dominated by mafic volcanic rocks, with smaller amounts of felsic volcanic and sedimentary rocks. The strata are folded about a large south-plunging F2 synformal anticline cored by mafic pillowed flows that host the Boston deposit. Gold mineralization is associated with a complex anastomosing high-strain zone which is roughly axial-planar to the main anticline and is tentatively interpreted as the latest expression of D2 strain. Overprinting the main (D2) structural elements is a series of cross folds (F3). The folding event that produced the latter created a large embayment of supracrustal rocks into the tonalite-granodiorite on the eastern side of the volcanic belt, and also deformed the gold mineralization and associated alteration at the Boston deposit.