PALEOECOLOGY OF THE SPRINGFIELD COAL MEMBER (DESMOINESIAN, ILLINOIS BASIN) NEAR THE LESLIE CEMETERY PALEOCHANNEL, SOUTHWESTERN INDIANA

The Springfield Coal Member (Carbondale Group, Petersburg Formation of Indiana) is split locally in Warrick and Gibson Counties, Indiana, by clastic rocks of the Folsomville Member (Carbondale Group, Petersburg Formation) that represent the Leslie Cemetery paleochannel, part of a large, interconnected paleochannel system in the Springfield coal bed . This study incorporated analysis of miospore and megaspore assemblag es, coal petrography, plant compression fossils and conodonts from the coal and clastic split to document changes in the swamp and its veget ation in response to the activity of the Leslie Cemetery paleochannel. Palynological and petrographic data indicate that environmental condi tions and vegetation in the lower bench of coal near the Leslie Cemete ry paleochannel were similar to those found in profiles through the co al bed at sites near the larger, more extensive Galatia paleochannel. Miospore floras of the high-vitrinite, lower bench of coal were domina ted by tree-fern miospores, with those of lycopsids ranking second in abundance; megaspore assemblages were dominated by lycopsid megaspores . Near the contact between the lower bench of coal and clastic split, medullosan prepollen increases in abundance and fusain bands are more common, which may indicate the occurrence of fire, either within or ou tside the swamp. Vegetation in the Folsomville Member and upper bench of coal differ markedly from that of the lower bench of coal. Plant me gafossils from the Folsomville Member indicate dominance by pteridospe rms and/or lycopsids and Folsomville Member miospores assemblages are dominated by lycopsid miospores most typically found in mudstones, inc luding Lycospora torquifer and higher than normal abundances of Granas porites medius. In the transition from clastic rocks of the Folsomvill e Member to the upper bench of coal, miospores of 'ecotonal' lycopsids (Paralycopodites) reach their peak abundance, pteridosperms dominate megafossil assemblages and inertinite levels are relatively high. At h igher levels of the upper bench of coal, vitrinite levels are higher a nd miospore assemblages are dominated by lycopsid miospores typical of coal swamps (Lycospora granulata, L. pusilla). The presence of conodo nts in coalballs in the upper bench of coal and spirorbid worms in the split indicate that the paleoswamp may have received some marine or b rackish water influence. Higher than normal salinity levels may explai n the vegetational changes observed in the upper bench of coal near th e Leslie Cemetery paleochannel.