Relationships among macerals, minerals, miospores and paleoecology in a column of Redstone coal (Upper Pennsylvanian) from north-central West Virginia (U.S.A.) (original) (raw)

1990, International Journal of Coal Geology

Two distinct paleoenvironments are represented in vertical succession in a column of Redstone coal in north-central West Virginia as indicated by a study of 37 consecutive 3-cm (0.1 ft) increments analyzed for ash yield, petrographic composition, low-temperature ash mineralogy and palynomorph abundances. Abundance profiles were constructed for ash, 12 petrographic components, 3 minerals and 5 miospore assemblages. The profiles and calculated correlation coefficients show close relationships between several constituents. Components that increased in abundance upward in the coal bed were a collinite type > 50 microns in thickness, cutinite, and miospores affiliated with calamites, herbaceous lycopods, cordaites and herbaceous ferns. Components that decreased in abundance upward were a collinite type < 50 microns in thickness, inertodetrinite, tree fern miospores, quartz, illite and ash yield. Components were correlated with ash yield to infer the swamp geochemical conditions that contributed to the low-ash (7%) upper one-third of the coal bed and the higher-ash (16%) lower two-thirds of the coal bed. Components that correlate positively with increased ash were the collinite type < 50 ttm thickness, inertodetrinite, tree fern miospores, illite and quartz. Components that correlate negatively with increased ash were the collinite type > 50 ttm in thickness, cutinite, calamite and cordaite miospores and kaolinite. Significant correlations occurred between ash yield and the collinite types > 50 and < 50 #m in thickness but no significant correlation was found between ash yield and total vitrinite-group content. This is interpreted to show that division of vitrinite macerals by size is important in petrographic paleoenvironmental studies. Paleoecologic interpretations based upon these correlations suggest that two distinct, planar, probably topogenous paleoecologic environments are represented in this column of the Redstone coal. The lower two-thirds of the coal bed was interpreted to have accumulated in a planar swamp in which significant introduction of detrital or dissolved mineral matter, and significant anaerobic and moderate oxidative degradation of the peat occurred. The flora of this paleoenvironment was dominated by tree ferns. The paleoenvironment during accumulation of the upper one-third of the coal bed was also interpreted to have been a planar swamp, but