Determining the Paleoclimate and Elevation of the Late Eocene Florissant Flora: Support from the Coexistence Approach

Published estimates on the paleoclimate of the Florissant fossil beds site of Colorado (34.1 Ma) have led to extremely different estimates of paleoelevation. The purpose of this paper is to review the paleoclimate methods used, and to add the Coexistence Approach (CA) method to estimate paleotemperature for the Florissant site. The basis of the CA method is the dependence on overlapping climatic requirements for different taxa in the flora and their nearest living relatives. These relationships tie the fossil identities to the actual plant habitats and climatic requirements of close relatives. Based on the CA method, we conclude that the mean annual temperature ranged between 14.3° C and 18.2° C. These results support the conclusions offered by several other studies that the Florissant was a warm-temperate to subtropical flora, and are consistent with recent conclusions by structural geologists as well as other studies indicating that the Florissant site was deposited at a relatively low elevation, probably between 1 to 1.5 km.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author