Exploration in the George River Group, Cape Breton

CIM Bulletin, 1971

G. C. MILLIGAN, Professor,
Dept. of Geology, Dalhousie University, Halifax, N.S.

A regional mapping program, conducted by the Nova Scotia Department of Mines, has shown that the George River Group of pre-Middle Cambrian rocks consists of a wide range of sedimentary and volcanic rocks, intruded by syenite, granite, granodiorite and lesser amounts of gabbro and diorite. Together, these rocks support the high ground of Northern Cape Breton Island. Over this large area, the metamorphic grade ranges from low to extremely high. The rocks were folded prior to emplacement of the intrusions in Middle Cambrian time, and there was also postMississippian disturbance and faulting, but the structural history and pattern are still only imperfectly understood. Sulphide mineralization is known at Meat Cove, Lime Hill and in a number of smaller deposits. The most Cavourable host rocks appear to be magnesian Iimestone, or schists derived from shales. Ail known sulphide bodies have an associated halo of retrograde metamorphism; in sorne cases, this is extensive enough to be used as a prospecting aid. A vein of nickel-bearing sulphides has recently been re-discovered in the former gold mine at Second Gold Brook- an association which appears to be unique.
Keywords: diorite, George River quarry, metamorphic grade, quartzite, syenite, Grade, Metamorphism, North, Quartzites, Rock, Rocks, sulphide, Sulphides