DEVELOPING A PROCESS-BASED UNDERSTANDING OF THE FACTORS CONTROLLING THE SEASONAL FORMATION OF PEDOGENIC CARBONATE

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Dr. Timothy M. Gallagher has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at the University of Texas at Austin. The investigation will focus on understanding the seasonal formation of carbonate minerals in soils. The project will consist of three components: laboratory experiments, computer modeling, and application of experimental and modeling results to a geological problem. The anticipated results will be of interest to a wide range of disciplines including those within the earth, biological, and soil sciences. Throughout this fellowship period Dr. Gallagher will actively convey the importance of environmental change to the general public through participation in events such as the University of Texas K-12 oriented Forty Acres Fest. In addition, he will mentor graduate students and develop and supervise independent research projects for undergraduates. Dr. Gallagher will co-teach an undergraduate environmental isotope geochemistry course, developing new assignments designed to expose students to the power and utility of computer modeling.The research project will take the novel approach of pairing experimental soil manipulations with cutting-edge reactive transport modeling in order to gain a thorough understanding of processes drivingpedogenic carbonate formation. The research plan will include (1) experimental manipulation of soil columns where different seasonal patterns of precipitation are simulated, (2) use of reactive transport models to place the experimental results of the research into a quantitative and predictive framework, and (3) application of the experimental and modeling results to a geologic case study centered on pedogenic carbonate derived paleoelevation histories of Andean uplift. Carbonate minerals in soils are an important archive of past environmental conditions, that is widely used by the scientific community for reconstructing past climatological, ecological and tectonic changes. The accuracy of these paleo-reconstructions is hindered, in large part because the processes controlling the seasonal timing of pedogenic carbonate formation have not been fully characterized. It is expected that this investigation will contribute to this knowledge gap.