Biometry and paleoenvironment of Retispora lepidophyta (Kedo) Playford 1976 and associated miospores in the latest Famennian nearshore marine facies, eastern Ardenne (Belgium)

The size diameter of Retispora lepidophyta, a stratigraphically important miospore, is reexamined in greater detail than in previous studies using three sections of the latest Famennian nearshore marine facies of the eastern Ardenne. The evolutionary character of the size reduction with time is confirmed and is used for accurate correlations between the three sections. Cluster analyses (dendrograms) are performed on the percentages of a selection of miospore species from the two most complete sections and show a clear analogy in the lateral distribution of R. lepidophyta and Vallatisporites hystricosus, a species known elsewhere (West Virginia, USA) to belong to coastal 'downstream' nearswamp plant communities [Streel and Scheckler, Rev. Palaeobot. Palynol. 64 (1990) 315-324]. By comparison also with the West Virginia data, three Diducites species are believed to represent the 'coal' swamp vegetation. A decrease in the proportion of the Diducites species from the lower to the upper portion of the studied sections is observed. Using biometric analysis, high resolution correlation between these sections reveals a lateral shift of facies with time during the latest Famennian in the eastern Ardenne. Local synsedimentary block-faulting processes were probably responsible.