Abstract

Fine-grained sedimentary rocks containing significant quantities of hydrocarbon (>50 mg/g Org C) occur in the Upper Cretaceous/Tertiary sediments of the Mackenzie Delta. These good to excellent potential petroleum source rocks are anomalous because they contain predominantly herbaceous and coaly organic matter (atomic H/C 0.8) and also because they occur at low levels of thermal alteration (vitrinite reflectance R₀ max ≤ 0.7). The large amounts of saturated hydrocarbon which were apparently derived from diterpenoid compounds and the presence of autofluorescent resins in the kerogen suggest that the high resinite content of the sediments may be the reason for the petroleum source potential in this geological setting. The geological parameters (physical, chemical, and/or biological) which controlled the spatial and temporal distribution of these resins is not well understood. Thus prediction of the location of optimum source rock zones has not yet been attempted. It is reasonable to assume, however, that there are other occurrences of this phenomenon and that several excellent potential petroleum source rocks do exist in this sedimentary basin.