Jennifer McElwain's research focuses on the use of fossil plant morphological, anatomical and physiological characteristics, to reconstruct atmospheric carbon dioxide (CO2) concentrations and associated changes in paleotemperatures, on time scales of millions of years, to decades and centuries. More specifically this research has involved investigation of leaf shape (physiognomy), stomatal frequency and stable carbon isotope ratios to elucidate (i) long-term evolution of atmospheric CO2 over the Phanerozoic, (ii) environmental changes associated with the Triassic-Jurassic mass extinction event, and more recently, (iii) carbon cycle dynamics and CO2-temperature interactions during rapid climatic events, such as the Younger Dryas stadial (~12,650 to 11,500 years BP). She is particularly interested in using fossil floras to investigate the environmental changes associated with a number of other, major and minor, faunal extinction events in Earth history, in order to ultimately decipher possible causal mechanisms. Future planned research includes (i) collection of fossil plant material spanning the Triassic-Jurassic boundary in Jameson Land, East Greenland, in order to investigate carbon cycle and vegetation dynamics spanning this important but understudied mass extinction event, (ii) further development of methodology used to estimate paleo-CO2 concentration from fossil plant stomata, and (iii) the development of a novel partial-pressure-based paleo-altimeter. Other Geology Department Research: Fossil Amphibians and Reptiles | Fossil Fishes | Fossil Invertebrates | Fossil Mammals | Fossil Plants | Meteorites | Paleontology