Geology of the Granby Fault, an Eocene Extensional Fault in Southeast British Columbia

The Grand Forks complex, northern equivalent to the Kettle dome in the United States (e,g, Cheney, 1977; Cheney, 1980; Rhodes and Cheney, 1981), is one of many exposures of high-grade metamorphic rocks of North American miogeoclinal affinity in the southern Omineca Belt (Figure 1). These structural culminations bounded by Tertiary normal faults, often collectively referred to as the Shuswap complex, were rapidly exhumed by tectonic uplift during post-Laramide crustal extension in the Eocene (e.g. Lorencak et al., 2001; Parrish et al., 1988; Vanderhaeghe et al., 1999). The western margin of the Grand Forks complex is the west-dipping Granby fault, which juxtaposes low-grade rocks of Quesnel Terrane to the west against the high-grade gneisses of the complex.