Stratigraphy and Palynology of the Westphalian Strata of the Leinster Coalfield, Ireland

Abstract

The Leinster Coalfield is the largest of the onshore coalfields in southern Ireland. Topographically and geologically the coalfield is an upland basin and the Westphalian sediments occupy the centre of the coalfield, while the older Namurian sediments form the rim. The Westphalian succession is approximately 320m thick and is subdivided into three lithostratigraphic formations: in ascending stratigraphic order these are the Moyadd Coal Formation, the Clay Gall Sandstone Formation and the Coolbaun Coal Formation. The latter formation is formally defined here and described, together with several new lithostratigraphic members. The first palynological study of the Westphalian strata in the coalfield has been carned out. The lower part of the Westphalian succession has been sampled palynologically from a stream section in the north of the coalfield, while the rest of the Westphalian strata have been sampled from three boreholes situated in the centre of the coalfield. Forty two miospore taxa have been identified from thirty productive samples. The miospore assemblages recorded are assigned to the Triquitrites sinani Cirratriradites saturni (SS) and Radiizonates aligerens (RA) biozones (Clayton et al. 1977) of Westphahan A (Langsettian) age. The stratigraphically important species Radiizonates aligerens first occurs within the Double Fireclay Member in the lower part of the Coolbaun Coal Formation. The SS / RA Miospore Biozonal boundary in the Leinster Coalfield is shown to closely correlate with the Lenisulcata-Communis non-marine bivalve Chronozone boundary.