Stratigraphic palynology of acritarchs from the type area of the Llandovery and the Welsh Borderland

Abstract

From the type area of the Llandovery in Wales 69 species and varieties of acritarchs are recorded; the Llandovery and Lower Wenlock succession of the Welsh Borderland has yielded 107 taxa; 59 species and varieties are common to both areas. The succession in the type area has been divided into four assemblage zones (1–4) and that of the Welsh Borderland succession is divided into four assemblage and one assemblage sub-zone(s) (2–5a). A stratigraphic correlation of the two areas is presented based on the relative incomings and outgoings of selected acritarch species. This indicates that the basal sequence in the Welsh Borderland corresponds to the upper part of assemblage zone 2 of the type area which is Idwian (Middle Llandovery) in age. With the aid of a “best fit” correlation curve, other horizons in the two areas are equated.