Although there is a consensus that major long-term global climate changes occurred during the Pennsylvanian in North America, there are fundamental disagreements in the frequency and magnitude of these inferred climate changes. Are the disparities in the inferred records of Pennsylvanian climates reflections of nonuniform methodologies? Or results of regional climate fluctuations? In this proposal it is planned to readdress this issue through an innovative approach in which the quantitative changes in the distribution of both clay-mineral and pollen and spore assemblages will be documented on individual rock specimens from selected continental sequences in the Appalachian Basin. The integration of combined clay/pollen study will provide high resolution analysis and at the same time allow the comparison of clay and pollen curves to isolated differences that may arise from employing different methodologies. Reconstructed climate changes will be compared against the Pennsylvanian climate trends established by other workers. In this proposal I will answer the following questions using microfacies studies and quantitative variations of the clay-mineral and pollen/spore flora assemblages across stratigraphic boundaries. 1) Are the aridities postulated for the early Middle Pennsylvanian and Late Pennsylvanian recorded in the clay mineral assemblages? 2) Are the abrupt climate changes suggested by plant extinctions during the two arid intervals indicated in the clay mineral assemblages? 3) Are there similarities in the onset of aridity between the earlier and later arid intervals? 4) Does the clay-mineral assemblages record minor climate fluctuations not indicated in the paleoflora or in the large-scale sedimentological features? This research will increase the understanding of Pennsylvanian climate changes, and assess the regional applicability of this rigorous and comprehensive approach in documenting climatic signatures from continental deposits.
