Age of Mineralization and Post-Ore HydrothermaI Alteration at Copper Mountain, B.C.

CIM Bulletin, 1968

A. J. SINCLAIR and W. H. WHITE, Department of Geology, University of British Columbia, Vancouver, B.C.

Unaltered biotites from three samples of monzonite and gabbro from the Copper Mountain stock and a single sample from a pegmatic biotitechalcopyrite vein cutting the Triassic Wolf Creek formation have a mean K-A age of 193±7 m.y. These data support a suggestion based on geological evidence that Copper Mountain ore deposits are related genetically to the Copper Mountain stock. A cogenetic mineral pair (biotite and clinopyroxene) from a sample of sericitized and chloritized monzonite of the Copper Mountain stock have identical K-A ages of 150 m.y., which probably represents a time of widespread, post-ore, hydrothermal alteration. This alteration is believed to be related genetically to a group of postore intrusions known as the "mine dykes," suggesting that they also have an age of 150 m.y.
Keywords: Biotite, biotite, clinopyroxene, Copper Mountain, British Columbia, pegmatitic, University of British Columbia, copper, geology, mineral, minerals, Rock, Rocks