The relationship of trangressive systems tracts to sea-floor diagenesis, Lower Cretaceous, Scotian Basin

Abstract

The Lower Cretaceous rocks of the Scotian Basin are deltaic, with cycles of delta progradation with relatively high sedimentation rates, capped by a transgressive unit with lower sedimentation rates. The diagenetic mineral phases in the sea-floor diagenetic system are commonly preserved where there is abrupt change in sedimentation rates, and also in coated grains found in the transgressive unit. This study assesses the role of seafloor diagenesis in the overall diagenetic system of the Lower Cretaceous of the Scotian Basin by studying the sedimentology, mineralogy, and geochemistry of the transgressive unit and underlying sediments from conventional core in two wells.

The observed variation in mineralogy and geochemistry of the different transgressive units can be tentatively related to their different facies associations. Those in younger strata at Peskowesk can be compared with modern sea-floor diagenetic systems in areas of high Fe availability. In shelf-edge deltaic deposits at Thebaud, there was higher Ca and Mg availability.