Variations in atmospheric CO_2 are related to climate change (especially temperature) throughout geological time. In order to elaborate more accurate actual palaeoclimatic models for the Cretaceous, several analytic methods will be combined on the fossil conifer cuticles of Frenelopsis (Coniferales, Cheirolepidicaeae) and its chosen nearest modem relative Juniperus. A calibration of the inverse relationship between stomatal density or stomatal index on leaves, and ambient concentrations of CO_2 and climates will be performed. Transmission electronic microscope observations (up to x 200,000) can result in the definition of ultra structural types in Frenelopsis cuticles (the actual leaf matenals) and be a direct record of external constraints and climatic oscillations. Sigma^13C measurements in the living and fossil plants can yield new information on the water constraints, irradiance, atmospheric pCO_2 and temperature. The ecophysiology, geochemistry and ultrastructure technique for study of the structure of conifer leaf cuticles can yield important contributions to understanding Cretaceous Plants and greenhouse climate.
I will learn new plant cuticle techniques (i.e. ultra-structure and geochemistry) and have access to important English fossil material. All necessary laboratory facilities are available at Leeds. I win receive support from an internationally renowned geochemistry group there and from the palaeobotanical group at Sheffleld that studies plant response to atmospheric CO_2 changes using carbon isotope analysis. I will benefit from the Cretaceous climate expertise of Dr Francis and her colleagues. I can also get extra training through their module in palaeoclimatology and the Centre for Biodiversity and Conservation (a Marie Curie Training Site). Ecophysiology, ultra structure and geochemistry of cuticles will be a new research field at Leeds and will complete the work undertaken here to determine ancient atmospheric CO_2 levels. This work will be of interest not only to the palaeobotanical group but other palaeontologists and environmental geochemists worldwide. New data for Cretaceous terrestrial climates will be produced to complement the information commonly derived from the marine record. The results will be published in international journals.