Cambrian palynology of the Bray Group in County Wicklow and South County Dublin, Ireland

The Cambrian Bray Group of southeast Ireland crops out in several areas, with its biostratigraphic dating generally poorly constrained. In its principal outcrop, that of the Bray-Wicklow district, a sparse, poorly preserved acritarch assemblage was recorded some years ago, suggesting a late Early to early Middle Cambrian age. In the present study 58 samples were collected for palynological investigation from throughout the group, of which four were productive. The productive samples occur in a geographically small area and lie within a 120-m-thick part of the Bray Head Formation which forms the upper part of the 4500-m-thick Bray Group. The palynological material is characterised by an abundance of Skiagia species of which Skiagia orbicularis (Volkova, 1968) Downie, 1982 is the most frequent. Particular attention was paid to the possible presence of the Middle Cambrian stratigraphic markers Cristallinium cambriense (Sklaviková, 1968) Vanguestaine, 1978 and Eliasum llaniscum Fombella, 1977. Our findings are that C. cambriense is not present and the occurrence of E. llaniscum cannot be definitely demonstrated. The presence and diversity of the Skiagia complex and the absence of the former taxa is indicative of a mid-late Early Cambrian age.