Isotope fractionation; Carbon; Early Earth; Diamond/Graphite; Carbonatites; Reduced Mantle
Wijbrans CH Rohrbach A Klemme S. (2016), An experimental investigation of the stability of majoritic garnet in the Earth’s mantle and an improved majorite geobarometer., in Contributions Mineralogy Petrology
, 171, 50.
Golubkova A Schmidt MW Connolly JAD (2016), Ultra-reducing conditions in the mantle: a thermo-dynamic model for SiC formation., in Contributions Mineralogy Petrology
, 171, 41.
Golubkova A Merlini M Schmidt MW (2015), Crystal structure and high pressure – high temperature behavior of carbonates on the K2Mg(CO3)2 – Na2Mg(CO3)2 join., in American Mineralogist
, 100, 2458-2467.
Wijbrans CH Klemme S Berndt J Vollmer C. (2015), Experimental determination of trace element partition coefficients between spinel and silicate melt: The influence of chemical composition and oxygen fugacity., in Contributions Mineralogy Petrology
, 69, 45.
Kang N Schmidt MW Poli S Franzolin E Connolly JAD (2015), Melting of FeCO3 to 20 GPa and thermodynamic properties of siderite melt., in Chemical Geology
, 400, 34-43.
Ghosh S Schmidt MW (2014), Melting of phase D in the lower mantle and implications for recycling and storage of H2O in the deep mantle, in Geochimica Cosmochimica Acta
, 145, 72-88.
Schmidt MW Gao C Golubkova A Rohrbach A Connolly JAD (2014), Natural moissanite – a low temperature mineral formed from highly fractionated ultra-reduced COH-fluids., in Progress Earth Planetary Sciences
, 1, 27.
Rohrbach A, Ghosh S, Schmidt MW, Wijbrans CH, Klemme S (2014), The stability of Fe-Ni carbides in the Earth's mantle: evidence for a low Fe-Ni-C melt fraction in the deep mantle., in Earth Planet Sci Lett
, 388, 211-221.
Kang N Schmidt MW Poli S Franzolin E Connolly JAD, Melting relations in the system FeCO3-MgCO3 and thermodynamic modeling of Fe-Mg carbonate melts., in Contributions Mineralogy Petrology
Kueter N Soesilo J Fedortchouk Y Nestola F Belluco L Troch J Wälle M Guillong M Von Quadt A, Tracing the depositional history of Kalimantan diamonds by zircon provenance and diamond morphology studies., in Lithos
The redistribution of carbon within the early Earth and the deep carbon cycle since Earth accretion is one of the most fascinating topics in modern petrology and geochemistry. This project is about how carbon moves and redistributes in the deep Earth. The tools to understand these transfers between different reservoirs are experiments (i) defining stabilities and compositions of minerals, melts and fluids involved, (ii) quantifying physical properties of carbonatites, and (iii) determining carbon (and nitrogen) isotope fractionation factors between minerals and liquids. In subproject A this project addresses Fe-carbide and Fe-C-melt involving redox equilibria that occur when subduction derived carbonatites reduce to elemental carbon in a metal bearing mantle. Furthermore we investigate the high pressure density and wetting angles of carbonatite melts which are key physical and thermodynamic properties of such melts. Their knowledge is necessary to understand melt percolation and to calculate phase relations of carbonatite melts. Subproject B investigates element and isotope fractionation of N and C between a reducing gas phase, representing the early reduced atmosphere, and a silicate or metal melt representing the magma ocean and suspended metal droplets therein. The experimental results will allow modeling C and N degassing from the magma ocean and establish C and N contents of primordial mantle and core material and to understand the related isotope fractionation. This project addresses the accretion stage of the Earth and its volatile budget. Finally, project C deals with recycling of carbon during subduction, its mobilizing in a fluid or melt and a possible re-precipitation in the mantle. We will investigate carbon isotope fractionation between the main carrier minerals of C (carbonates, graphite, diamond, carbides) and fluids, carbonatites or C-rich silicate melts. This project will constrain changes in the C-isotope composition during recycling into the mantle, the transport ways of carbon in the deep Earth (through the related isotope fractionation) and quantify e.g. the effects of Rayleigh fractionation on the C-isotope composition of diamonds.