Facies breaks in the Scottish Passage Group and their possible correlation with the Mississippian—Pennsylvanian hiatus

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Abstract
Synopsis: The Scottish Passage Group (Namurian E 2 to Westphalian A) contains many minor disconformities, but its thickest and most complete development in the Kincardine Basin east of Stirling reveals only three major depositional breaks or facies changes sufficiently important to be considered as possible correlatives of the Mississippian-Pennsylvanian hiatus of North America. They are here named Horizons 1 to 3. Even in the area of maximal subsidence, Horizon 1 just above the Castlecary Limestone is marked by deep channelling. Despite the following flood of coarse sandy detritus, widespread marine transgressions continued (Nos. 1 to 2 Marine Bands). Horizon 2, which lies just above No. 2 Marine Band, heralded a regressive period with meandering river environments and only one local marine incursion. Above No. 3 Marine Band Group with its renewed widespread marine transgressions, Horizon 3 marks the onset of another regressive period when marine bands became impersistent, thin and faunally impoverished, e.g. Nos. 5 and 6 Group, overbank ‘fines’ were seldom preserved and braided rivers possibly became dominant. Horizon 1 is much the best example of a major regression during the Scottish Namurian. Nevertheless biostratigraphical evidence favours Horizon 2 as being more probably equivalent to the Mississippian-Pennsylvanian hiatus.