Pliocene temperatures from the tropics: the Eastern Cordillera of Colombia

Graduate student Lina Perez-Angel and CIRES Fellow Peter Molnar plan to make the first reliable, quantitative estimates of surface temperatures from the tropics for Pliocene time  (5.3-2.5 million years ago). This was the last time when global temperatures were similar to those expected for the late 21st Century, and when CO2 concentrations may have been as high as today's, about 400ppm. A recent summary of Pliocene temperatures included no sites within 10° of the equator; Perez-Angel and Molnar plan to fill that data gap. Their work will involve both fieldwork (collecting samples for calibration, for estimating Pliocene temperatures, and for dating) and laboratory analysis (two main techniques: a proxy that uses the distribution of soil bacterial branched glycerol dialkyl glycerol tetraethers and cosmogenic burial dating through the Purdue Rare Isotope Measurement Laboratory). A by-product of this study may be constraints on the elevational history of the Eastern Cordillera, which has posed some challenges for geodynamicists.