Carbonate clumped isotope thermometry : principles, challenges and applications at IPGP

While most of the history of stable isotopic geochemistry focused on the concentrations of molecules containing only one rare isotope, clumped isotope geochemistry defined in 2004 focus on the extent to which rare (heavy) isotopes bond with each other rather than with the surrounding abundant light isotopes. It has become an increasingly important field in geochemistry over the last decade with particular interest on carbonate clumped isotope thermometry (?47) that show unprecedented promises for reconstructing past temperature in a variety of geological settings. Such potential relies on the fact that ?47 thermometry is based on the thermodynamic preference of 13C and 18O to bond with each other inside the mineral lattice at low temperatures. This proxy therefore does not require to know the isotopic composition of the water from which the carbonate has grown (a main limitation of the traditional and extensively used ?18O temperature proxy). Here I will describe some key applications of the ?47 proxy in multiple fields of research (e.g., paleoclimatogy, water-rock interactions and carbonate diagenesis, geospeedometry, paleoaltimetry) as well as fundamental work currently carried out at IPGP to refine methodological and interpretational frameworks of this emergent proxy.