Isotope effects in carbonate minerals: Proxies for environmental changes and biosignatures

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Carbonates such as calcite and aragonite are among the most abundant minerals on the surface of the Earth. Due to their natural ubiquity, these carbonate minerals have frequently been the subject of physical, chemical, and geological studies. In particular, Earth scientists and paleoclimatologists have long used the geochemical properties of marine and continental carbonates to decipher Earth's past environmental variations, providing paleoenvironmental records for the development of accurate climate models that are capable of future climate prediction. For example, corals, cave deposits, fish ear-bones, and shells of marine plankton have been invaluable carbonate climate archives in the fields of paleoclimatology and paleoceanography. With the financial assistance of the Discovery Grants program, my research group will characterize multiple geochemical properties of laboratory-grown carbonates depending on their growth conditions. The mechanisms of these environment-sensitive geochemical signatures will then be identified, establishing theoretical baselines to develop new innovative geochemical tools to better extract the past environmental changes, as well as the fingerprints of biological activities recorded in carbonate minerals when they formed.*******The long-term goals of my research program are (1) to work toward a thorough understanding of the isotope effects observed in various carbonate-water systems, and thus (2) to develop a unifying model by which these physicochemical processes can be predicted on the basis of experimental and/or observational studies in the laboratory or in the field. To achieve these research goals, my research group will perform a series of laboratory experiments designed to closely mimic the growth conditions of natural carbonates using my state-of-the-art research facilities. Subsequently, we will carefully monitor the isotopic variations of multiple elements (e.g., boron, calcium, carbon, lithium, magnesium, oxygen, and clumped isotopes) in these synthetic carbonates as a function of different formational conditions and biological activities. The outcome of my research program will provide our community with more reliable scientific tools to reconstruct Earth's environmental history and also to predict future climate changes. This ability to forecast short- and long-term future climate variability will allow policymakers to prepare relevant government policies and regulations in a timely manner, ensuring many potential social, cultural, and economical benefits to the residents of Canada. Furthermore, our research outcome will also allow the use of carbonate minerals in many other fields of science, such as astrobiology where carbonate minerals could be used to determine potential biosignatures from extra-terrestrial materials.***