9418424 Raymond Paleophytogeography, the study of the distribution of ancient land plants, helps us to understand the nature of ancient climate change and how climate change affects land-plant diversity. The data for paleophytogeography studies come from two sources: macrofloral assemblages (accumulations of fossil leaves, stems, seeds and other plant parts) and spore-pollen assemblages. Compared to macrofloral assemblages, spore-pollen assemblages are easier to assign to narrow intervals of geologic time, have higher generic and species diversity, and may derive from a wider range of habitats (particularly more arid habitats). These factors suggest that spore-pollen data should yield detailed and accurate phytogeographies; however studies of spore-pollen and macrofloral phytogeography for the same interval seldom produce congruent results. This proposal seeks funding to compile a mid-Carboniferous (333 to 315 Ma) spore-pollen database, identify and apply appropriate multivariate statistical techniques (including the Raup-Crick probabilistic similarity index, cluster analysis, and ordination techniques such as multidimensional scaling and reciprocal averaging analysis) for the phytogeographic analysis of spore-pollen data, and to complete phytogeographic studies of the mid-Carboniferous Eumorphoceras-, Homoceras-, Reticuloceras-, and Cancelloceras (G1)-goniatite zones (Namurian A through C). Completion of this work will require detailed knowledge of North American spore-pollen assemblages during the mid-Carboniferous. Thus, spore-pollen assemblages from the mid-Carboniferous of Kentucky, Alabama, Utah, and perhaps Nevada will be collected, studied, and described as a part of this project. This will result in an improved spore-pollen biostratigraphic zonation for North America during the mid-Carboniferous, and improved global correlation for this interval. The study interval includes the Early/Late Caroniferous boundary and coincides with the Laurussia-Gondwana collision as well as glacial onset in the Southern Hemisphere, high-latitude cooling in the Northern and Southern Hemispheres, and perhaps mid-latitude and equatorial climate change as well. The results will establish the nature and timing of equatorial and mid-latitude climate change, yield insight into the development of ever-wet, ever-warm equatorial and dry mid-latitude floral communities as a result of glacial onset and/or continental collision, and document the effect of glaciation and continental collision on land-plant diversity.
