ABSTRACT

Upper Tertiary (Neogene) rocks of the Beaufort Basin consist of unconsolidated carbonaceous sand, gravel and mudstone. Lower Tertiary (Paleogene) rocks, up to 15,000 ft (4600 m) thick, are repetitive grey sandstones, mudstones and shales with some coaly stringers, and contain the Taglu producing sands. Marine, brackish and freshwater sediments of mostly nearshore, shallow-water environment are represented. This paper presents preliminary biostratigraphic correlations for these rocks. Two methods involving simple statistics, the general assemblage composition and a few marker fossils are discussed for four wells. Foraminifers are mostly of benthonic arenaceous type. Dinoflagellates are confined to a few zones, with Wetzeliella hampdenensis marking a zone above the producing Taglu sands. Variations in relative frequency of palynologic fossils are pronounced, reflecting changes in the flora of adjacent land areas, which mostly were under the influence of a temperate climate. Problems are many, including reworking of fossils from Late Cretaceous and earlier Tertiary beds into younger Tertiary strata. Seismic correlations suffer from local problems, including variable permafrost. The statigraphy is complicated by faulting, sand-shale facies, uneven erosional truncation beneath the unconformable cover of Neogene beds, and the limited number of wells with complete Tertiary penetration.

Data presented have been prepared by the paleontological staffs of Gulf Oil Canada, Imperial Oil Limited and Mobil Oil, with supplementary material from Shell Canada Limited.