Carboniferous palynology of the East Dron Borehole: a preliminary report

This preliminary report describes palynological analysis of 20 samples from the interval 221.69-25.68m in the East Dron Borehole, Fife (NO 1360 1572). The borehole was sampled for palynology in the early 1970s by Dr R. Neves of the University of Sheffield, and more recently by BGS staff for ostracods. The slides made at the University of Sheffield have only recently (Jan 2002) been recovered and these and new slides made from samples taken for ostracods form the basis for this report.
The sequence yielded a relatively large number of rich assemblages whose preservation is notably better than those of the Glenrothes Borehole and approximately similar to those at the Heads of Ayr coastal section, though 5 samples from the lowest part of the borehole (221.69-203.24m) were barren. CM Biozone (Tn3c; latest Tournaisian) assemblages are present from 189.4m to the top of the studied section.
Detailed ostracod data is available between 72.29m and 24.35m and this indicates that brackish or quasi-marine conditions dominated within this section (Williams 2002).
On the basis of this and earlier studies, and other published information on the Spilmersford, Birnieknowes and Cockburnspath sections, a preliminary correlation for the MVS Ballagan Formation is suggested (Fig. 2). ‘Upper Ballagan’ assemblages from the Heads of Ayr are not present in Glenrothes and East Dron, hence it could be argued that younger parts of the Ballagan Formation are present in the Heads of Ayr section. Even younger parts of the Ballagan Formation are present, however, in the Spilmersford and Birnieknowes boreholes where Pu Biozone (earliest Viséan) assemblages have been recorded.
Table 1 presents sections in which CM/Pu Biozone assemblages have been identified from the Ballagan Formation, but most are poorly know biostratigraphically. It is recommended that a number of these be further sampled for palynology and ostracods with a view to:
• further developing biostratigraphical subdivision of the CM Biozone,
• cross referenced investigations of the CM-Pu (approximately the Tournaisian- Viséan) boundary.