Lithofacies and stratigraphy of a Dinantian non-marine dolostone from the Lower Oil-Shale Group of Fife and West Lothian

A Dinantian Lower Oil-Shale Group sedimentary rock sequence from Colinswell in the Burntisland district of Fife contains sandstones, shales and carbonate rocks. From facies analysis the sandstones are interpreted as proximal deltaic channel-mouth bars whilst the shales and carbonates represent low-salinity interdistributary bay facies. One distinctive dolostone unit which is laminated and brecciated is interpreted as a former stromatolitic mudflat which underwent subaerial exposure and desiccation. Given the general stratigraphic position of this sequence between the established marker horizons of the Burntisland Marine Band (= Pumpherston Shell Bed) and the Burdiehouse Limestone, rocks of similar age, the Queensferry Beds, were studied at outcrop in West Lothian. At both South Queensferry and Hopetoun (West Lothian) a remarkably similar dolostone unit to that at Burntisland was identified within the Queensferry Beds. It is proposed that these dolostone beds are lateral equivalents, formed during a basin-wide ‘regressive event’. Correlation of the dolostones not only improves the local Lower Oil-Shale Group stratigraphy, it provides a time marker from which to analyse local facies variation in the underlying and overlying delta-derived sandstones.