LOWER AND LOWER MIDDLE PENNSYLVANIAN COAL PALYNOFLORAS, SOUTHWESTERN VIRGINIA

Lower and lower Middle Pennsylvanian coals, recovered from an explorat ory drilling program in southwestern Virginia, were analyzed for their palynomorph content. Results show them to be dominated by spores prod uced by arboreous lycopsids. Lycospora pellucida and Lycospora pusilla generally are the most common species, with others, namely Lycospora granulata, L. micropapillata and Lycospora orbicula being locally abun dant. Densosporites, Cristatisporites, Radiizonates and Cingulizonates , representing small lycopsids, and Granulatisporites, produced by sma ll ferns, and perhaps some pteridosperms typically are sub-dominant ta xa. The recovered palynofloras are similar in overall composition maki ng individual coal bed identification and correlation very difficult, if not impossible. However, the introduction and extinction of a few f orms do assist the correlation of packages of strata, on both an intra - and interbasinal scale. Dictyotriletes bireliculatus is first observ ed in basal Lee Formation strata, at about the level of the Cove Creek coal bed. Radiizonates aligerans and R. striatus also appear more abu ndantly at this level, although some forms have been observed in older , Pocahontas Formation coals. This level essentially coincides with th e Namurian C/Westphalian A boundary, based on plant megafossil evidenc e. Laevigatosporites minor, L. vulgaris, Endosporites globiformis, E. zonalis and Granasporites medius are first seen consistently just abov e the Sewell coal bed. Radiizonates aligerans, R. striatus and Densosp orites irregularis are last seen in the early Middle Pennsylvanian, at about the level of the Splash Dam coal bed. Schulzospora rara occurs throughout Early and early Middle Pennsylvanian strata, and is last se en in the Manchester coal. The Manchester is directly overlain by the Betsie Shale, a widespread marine unit; the base of the Betsie marks t he Westphalian A/B contact. When compared with palynomorph assemblage zonations published for the Western Interior, and Eastern Interior Bas ins, Early and early Middle Pennsylvanian palynofloras from the Centra l Appalachian Basin compare most favorably with early Morrowan strata. Analysis of bench samples indicates that Lycospora typically dominate s basal and middle portions of Early and early Middle Pennsylvanian co als. More terminal layers often contain higher percentages of Granulat isporites (and related trilete, sphaerotriangular genera, e.g. Lophotr iletes, Acanthotriletes, Deltoidspora) and Densosporites (and related trilete, crassicingulate genera, e.g. Cristatisporites, Cingulizonates , Radiizonates). This temporal change is consistently observed and may primarily reflect a water table change within the paleomires from con sistently high (covered with water or at least water-logged most of th e time) to intermittently low (occasional substrate exposure).