Eocene Floras of the Northern Hemisphere: Paleoclimate and Implications for Large Scale Floristic Interchange

University Of Florida, Gainesville FL

Investigators

Abstract

Eocene floras of the Northern Hemisphere: paleoclimate and implications for large scale floristic interchange Stephen Manchester EAR-0087780 Abstract Detailed first-hand comparisons will be made between selected early and middle Eocene floras of mid-latitude North America, Europe and Asia through collaboration with colleagues in Germany and China as a means of assessing phytogeographic patterns during a time when the climate was warmer than today, and there was potential for high-latitude floristic exchange between continents. PI will compare megafossil floras preserved in the sediments of early and middle Eocene lakes from North America (West Branch Creek and Green River floras, western US), western Europe (Messel and Eckfeld, Germany), and Eastern Asia (Fushun and Huadian, China). The ages of each these assemblages are established through correlations of associated mammal faunas and/or radiometrically dated volcanic ashes. Paleoclimate of each of the sites will be compared based on foliar physiognomic analyses to give approximations of mean annual temperature and precipitation. Intra- and intercontinental floristic comparisons will be made to determine the relative proportion of shared vs. endemic taxa between each pair of continents in the early and middle Eocene. The resulting observations will: 1) provide approximations of the mean annual temperature and precipitation of these widely separated lake basins, 2) indicate the relative importance of different routes of intercontinental dispersal in the early and middle Eocene, and 3) facilitate comparison of dispersal patterns in plants with those observed in mammals during the early Tertiary.