Major Cycles of Transgression and Regression (Mesothems) in the Namurian

SUMMARY Some general principles about sedimentation resulting from major eustatic cycles in the Dinantian are applied to a reinterpretation of north of England Namurian successions in terms of major cycles of transgression and regression. Significant faunal renewals occur immediately subsequent to the development of more than usual regressive features. Eleven major cycles are distinguished in the Namurian of Britain. Such cycles are unconformity-bounded on shelf or ‘block’ areas (where the basal faunas of each major cycle are missing) and the term mesothem is recommended for them. A brief survey suggests that these cycles are widely applicable in the northern hemisphere and are of eustatic origin. Their significance in terms of a proposed new generally-applicable stratigraphical boundary in the middle of the Namurian is discussed.