Der Einfluß von Druck, Temperatur und Sauerstofffugazität auf die Stabilität subduzierter Karbonate und Konsequenzen für den Kohlenstoffkreislauf im Erdinneren

• Antragstellerin: Privatdozentin Dr. Catherine McCammon
• Fachliche Zuordnung: Mineralogie, Petrologie und Geochemie
• Förderung: Förderung von 2013 bis 2018
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 236945944

Surface processes play an important role in the cycling of carbon through the atmosphere, oceans and shallow surface environment; however carbon also cycles through the Earth's deep interior, which may contain a large proportion of terrestrial carbon. The goal of the project is to use an experimental approach to determine the chemical and physical properties of phases in the system FeCO3-CaCO3-MgCO3 that are relevant to quantifying the deep carbon cycle. We will use a laser-heated diamond anvil cell to simulate conditions in the deep Earth, coupled with X-ray diffraction and nuclear resonance methods (including Mössbauer spectroscopy) established at in house and third-generation synchrotron facilities to probe the structural and electronic state of carbonate samples in situ at high pressure and temperature. We will address the following scientific questions in our project: (1) Which phases are stable in the system FeCO3-CaCO3-MgCO3 at pressures and temperatures down to the base of the lower mantle? (2) Which phase(s) is/are the dominant carrier of carbon into the deep mantle? (3) What is the stability of the dominant carbon carrier phase(s) with respect to oxygen fugacity at pressures and temperatures down to the base of the lower mantle? (4) What are the valence and spin states of iron in the dominant carbon carrier phase(s) at pressures and temperatures down to the base of the lower mantle? The answers to these questions will be used to construct a new model for the deep carbon cycle that identifies the pathways for carbon exchange and quantifies the fluxes along those pathways.

• DFG-Verfahren: Sachbeihilfen
• Beteiligte Personen: Professor Dr. Leonid Dubrovinsky; Professor Dr. Daniel J. Frost