PALEOECOLOGY AND TAPHONOMY OF MIDDLE PENNSYLVANIAN-AGE COAL-SWAMP PLANTS: HERRIN COAL-BALL PEAT AND COAL, PEABODY CAMP 11 MINE, HERRIN COAL, WESTERN KENTUCKY.

摘要

The objective of this research was to develop a method for analyzing the flora of Pennsylvanian-age coal swamps directly from etched polished surfaces of coal. Vegetation of two coal-ball profiles and four coal-column samples from the Herrin Coal Member (Kentucky No. 11), Carbondale Formation at Peabody Coal Company's Camp 11 mine in western Kentucky were compared. An estimated 89.5% of the coal can be anatomically identified. The estimated abundances of major plant groups (lycopods, ferns, and pteriodosperms) in coal-ball profiles and in coal differ by less than 10% after accounting for differential compaction of plant tissues. Standard deviations in taxonomic and maceral composition among coal columns are generally less than 2%.;In the coal, pteriodosperm abundance is positively correlated with underlying shale partings showing that pteridosperms are favored by either higher nutrient levels or disturbance. Fungal remains in coal balls usually are preserved as vitrinite.;The occurrence of Lepidophloios cf. johnsonii at Camp 11 extends the range of the Lepidophloios wunschianus group.;In the third of the four benches in the seam a succession from Sigillaria-containing zones to zones dominated by Lepidophloios hallii is interpreted as a shift towards wetter conditions. In the remainder of the seam profile, the main factor controlling the taxonomic composition appears to have been the relative abundance of nutrients and/or the frequency of disturbance as indicated by the relative abundance of partings.;During burial, individual plant tissues become more compact but intrusion of secondary rootlets causes the peat as a whole to change little in degree of compaction. The lowest and uppermost layers of the peat appear to have decayed the most.;Criteria for distinguishing between domed and planar swamps are discussed. These include: distribution of partings, type of plant succession, and changes in diversity, average plant size, preservational quality and sporinite content. The only evidence favoring the possible development of a peat-dome is the infrequency of mineral partings in the third of the four benches.