Sedimentology, Stratigraphy and Geochronology of Deep-Water Upper Slope Deposits, Neoproterozoic Windermere Supergroup of Western Canada

Abstract

The stratigraphic architecture and depositional character of upper-slope channel–levee systems in the Neoproterozoic Isaac Formation is investigated. Detailed section measuring, mapping on high-resolution aerial drone images, and comparison with documented lower-slope channel complexes reveal that upper-slope channels are markedly thinner yet substantially coarser grained, exhibit deeper incision and more extensive cannibalization with pervasive mudstone-clast breccia. In contrast, levee deposits are comparatively finer-grained and dominated by upper-division turbidites. These patterns suggest that turbidity currents were typically undercapacity over the steep upper slope, resulting in prolonged erosion and confinement before transitioning to overcapacity, and therefore depositional conditions downslope. Despite these differences, detrital zircon assemblages, reflecting sediment provenance, and the evolution of channel complex architecture resemble those documented farther downslope, suggesting that temporal and spatial changes in these attributes are related to granolumetric changes along the source to sink profile and to flow hydraulics controlled by position along the continental slope.