Barremian to albian stratigraphy, Tuktoyaktuk Peninsula and south Mackenzie delta, Northwest Territories

Abstract

Barremian to Albian strata of the Parsons Lake and south Mackenzie Delta areas have distinct seismic stratigraphic expression, geophysical log responses and foraminiferal assemblages. Data from these sources have led to the revision of formational boundaries, such that a much thicker, Albian, Arctic Red Formation and a thinner Mount Goodenough Formation are now recognized. The Mount Goodenough succession contains a distinctive assemblage of Barremian agglutinated and calcareous benthic foraminifers, readily differentiated from Albian forms. Mount Goodenough strata can be correlated with the whole of the Atkinson Point Formation, not just the upper part, as was previously concluded. Also, the Siku Formation is reduced in rank to a member of the Mount Goodenough Formation. Arctic Red strata are divisible into three informal members, lower, middle and upper, corresponding to three seismic facies; downlapping bottomset, foreset clinoforms, and onlapping reflections respectively. The boundaries between each member and between the Arctic Red and the underlying formation also have distinct log responses, usually abrupt changes in gamma-ray count and/or sonic transit time. The Arctic Red succession also contains three distinct foraminiferal assemblages: a lower unnamed assemblage (the Lower member assemblage), a middle Quadrimorphina albertensis assemblage, and an upper assemblage tentatively assigned to the Verneuilinoides borealis assemblage. The middle and upper assemblages indicate an Early Albian age for that part of the Arctic Red Formation. The lower assemblage is not agediagnostic.