Foraminiferal biostratigraphy of Brigantian-Arnsbergian limestones from eastern Scotland and Northumberland (northeast England)

Abstract

ABSTRACTForaminifers, calcareous algae and incertae sedis Algospongia of late Asbian to late Brigantian age in limestones from East Fife, East Lothian and Northumberland, enable the base of the late Brigantian to be recognised in all these areas. Preservation of the late Asbian and early Brigantian limestones in cyclothemic successions is generally poor. The St Monans White Limestone (St Monans, Fife), First Abden Limestone (Kirkcaldy, Fife), Middle Longcraig Limestone (East Lothian) and Lower Bath-House Wood/Middle Bath-House Wood (Northumberland) were confidently correlated by their foraminiferal assemblages. These limestones are all assigned to the top of the Assemblage 6 in northern England (Single Post Limestone). The St Monans Brecciated/St Monans Little/Charlestown Main limestones (St Monans, Fife) and the Second Abden/Seafield Tower limestones (Kirkcaldy, Fife), Upper Longcraig/Lower Skateraw limestones (East Lothian), Upper Bath-House Wood/Shotto Wood limestones and Eelwell Limestone (Northumberland) are assigned to the Assemblage 7 in northern England (Scar Limestone and Five Yard Limestone). The paired Middle/Upper Skateraw limestones (East Lothian) and the Acre Limestone (Northumberland) contain representatives of the Assemblage 8 from northern England (Three Yard Limestone). Higher up in the succession, in Northumberland, the foraminiferal assemblage in the Sandbanks Limestone can be compared with Assemblage 9 in northern England (Four Fathom Limestone). Above the Great Limestone and Little Limestone, with their characteristic Pendleian assemblages, the Sugar Sands Limestone and Corbridge Limestone contain Arnsbergian foraminiferal assemblages, typical of the Lower Felltop Limestone in northern England. The Lower Foxton Limestone is correlated with the Upper Felltop Limestone, whereas the Thornbrough Limestone in Northumberland lacks diagnostic Arnsbergian taxa.