COLLABORATIVE RESEARCH: Tropical Vegetation during the Early Part of an Ice Age: An Intercontinental Comparison of Mid-Carboniferous Floras in their Geochronologic Setting

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

Collaborative Research: Tropical Vegetation during the Early Part of an Ice Age: An Intercontinental Comparison of Mid-Carboniferous Floras in their Geochronologic Setting Hermann Pfefferkorn EAR-0207848 ABSTRACT Earth history records major climatic intervals that can be generalized as either globally warm or cold. Transitions to a globally cold Earth, representing the onset of an ice age in the broadest sense, has happened only a few times since the establishment of terrestrial ecosystems, for instance in the Carboniferous and Late Tertiary (at the beginning of our current cold climate phase). At such times of transition, there are expected to be significant changes in the flora in all environments and at all scales. This project focuses on the changes in tropical terrestrial floras during the initial phases of the Carboniferous ice age, up to and immediately after the Mid-Carboniferous boundary (320 Ma). Fossil plant-bearing rocks from coal basins in the United States, Poland, and the Czech Republic provide remarkably stratigraphically complete macrofloral and microfloral data sets, which have been collected for decades from rocks overlying the coals (macroflora) and the coals themselves (microflora). Additionally, volcanogenic ash-fall tuffs have been identified within some sections, providing minerals that can provide isotopic ages, permitting control of biostratigraphic correlations within and between the basins and other parts of the world. From these unpublished data and the supporting collections, a standard reference profile of vegetational changes will be established that will document the rates of taxonomic turnover through time. These data will allow for a quantitative analysis of the geographical extent and dominance-diversity magnitude of vegetational community changes in the tropics. Results from this project can serve as a baseline for the study of similar intervals in our current ice age.