Structural Geology of the Cariboo Gold Mining District, East-Central British Columbia

Abstract

The Cariboo gold mining district extends from Big Valley Creek in Wells map area southeast to Cariboo Lake and is entirely within the Quesnel Highlands. Proterozoic to Jurassic rocks are bound by thrust and strike-slip faults into four tectonically and stratigraphically unique terranes. All rocks of the terranes were deposiled in an ocean and vary, east to west, from continental shelf claslics and carbonates (Cariboo Terrane) through continental shelf and slope clastics, carbonates and volcaniclastics (Barkerville TerraneJ, and rift floor pillowed basalt and chert (Slide Mountain Terrane), to island arc volcanic/astics and fine grained clastics (Quesnel Terrane). Mesozoic shallowly-dipping faulls have shortened the distance between the terranes and late Mesozoic and Tertiary moderately- to steeply-dipping (probably listric) faults have shorrened, translated and extended the stacked terranes. Mesoscopically, the structure is dominated by east- and west-verging multiple folds, but regionally by shear, as expressed mainly by transpressional terrane boundary faults. The structural stacking and disruption of the terranes was accompanied by regional prograde and retrograde metamorphism which subjected most of the area to chlorite grade, and the extreme southeast to kyanile grade.