This award supports the development of methods to determine paleo-elevations from the physiognomy of fossil plants and to apply the methods to constrain the history of regional elevation changes of western North America. Using multivariate statistics, correlations will be sought among physiognomic characteristics of plant assemblages, various average temperatures (mean annual temperature, mean daytime temperature, mean summer temperature, etc.), and various average moisture parameters (relative humidity, vapor pressure, or mixing ratio of vapor to dry air). The goal is to determine what average temperature and what moisture parameters can be determined from fossil assemblages, and what uncertainties characterize such determinations. Simultaneously, meteorological data will be used to search for thermodynamic variables of the atmosphere that are as independent of altitude and longitude as possible. Specifically, the moist static energy and the equivalent potential temperature will be calculated using mean temperatures and corresponding mean mixing ratios for meteorological stations in North America. In combination, these parameters will determine paleo-altitudes and allow a better determination of climate and environmental history.
