UPPERMOST DEVONIAN AND LOWER CARBONIFEROUS STRATIGRAPHY, SEDIMENTATION, AND DIAGENESIS, SOUTHWESTERN DISTRICT OF MACKENZIE AND SOUTHEASTERN YUKON TERRITORY

The uppermost Devonian and Carboniferous in SW District of Mackenzie and SE Yukon Territory form a thick succession of continental terrace wedge deposits. These comprise: a shale lithosome that intertongues eastward with a lower interval of dominantly terrigenous slope and shelf facies (upper Banff and coeval Yohin formations); a middle succession with carbonate-platform facies (ascending order: Pekisko, "Shunda", Prophet, and Flett formations); and an upper interval of delta facies (Mattson Formation). Basinal and prodelta shale in the upper Besa River Formation constitute the western part of the shale lithosome; and, proceeding upward, the lower Banff, Clausen, and Golata formations are its eastern tongues. The lower Banff is mainly basinal shale. Neritic shelf limestone and sandstone occur in the regressive upper Banff. Graded beds of siltstone, sandstone, and limestone dominate slope to shelf facies of the lower Yohin, which overlies the Besa River; the upper Yohin is chiefly shallow-neritic sandstone. Four carbonate platforms, which prograded westward and comprise coeval belts of shallow- to deep-water facies, are present. Platform shelf limestone constitutes most of the Pekisko, which abruptly overlies the Banff. The cyclic Prophet platform facies gradationally overlie Besa River and Clausen basinal shale, are mainly chert-rich lower slope spiculite and limestone, and both underlie and pass eastward into more proximal, "Shunda" and Flett, platform deposits. The cyclic Flett overlies the Prophet and "Shunda", and is mainly shelf margin and middle to upper slope limestone. Yohin, Prophet, and Flett slope facies have submarine channel scars. The Golata, mostly prodelta shale, conformably overlies Prophet and Flett facies. Mattson deltaic sandstone overlies and passes westward into the Golata and upper Besa River. Calcite cement precipitated in meteoric-phreatic and subsurface zones, and siliciclastics had a northern, dominantly sedimentary provenance.; The name Rundle Group (comprises: Pekisko, "Shunda", Prophet, Flett, and locally Clausen) is extended into the area; Etanda Formation is abandoned. The Flett is redefined to exclude the Prophet and Golata, and is subdivided into the Tlogotsho, Jackfish Gap, and Meilleur members.; Thirteen surface and 16 subsurface stratigraphic sections provided data. Palynomorphs, foraminifers, corals, and conodonts provided biostratigraphic control.