Sedimentology and ichnology of an Early-Middle Cambrian storm-influenced barred shoreface succession, Colville Hills, Northwest Territories

Abstract This study presents the first detailed sedimentological and ichnological study of the Cambrian Mount Clark Formation from the Colville Hills region of the Northwest Territories, Canada. Based on analyses of four industry drill cores, eight lithofacies are identified that occur in a recurring facies association. This facies association records a progradational storm-influenced shoreface succession preserving offshore to upper shoreface sedimentary environments. Storm influence is indicated by the presence of hummocky cross-stratification (HCS) and of tempestite/fair-weather couplets consisting of low-angle cross-bedded sandstone with thin bioturbated interbeds. Marine flooding surfaces are expressed as pebbly transgressive lags that separate near-shore and overlying offshore sedimentary environments. Piperock is common, represents the most oil stained lithology, and is preserved within a wave-dominated shoreface succession. The sedimentological and ichnological character of this succession suggests that predictable shoreface stacking patterns and sandstone distributions characterize the Mount Clark Formation in the subsurface of the study region.