Petrology and Geochemistry Dr. Ralf Dohmen Research Scientist Pulsed Laser Deposition Laboratory Manager Dr. Ralf Dohmen Photo by Raúl Fonseca Dr. Ralf Dohmen (Dr. rer. Nat. 1999, Köln, Germany) E-Mail - ralf.dohmen@rub.de Tel.: +49 234 32-24394 Raum: IA 4/113 Research Interests Experimental and theoretical petrology. My research interest covers various different topics within theoretical and experimental petrology where diffusion or diffusion-controlled processes are involved. It comprises theoretical modeling as well as experiments to understand and quantify the reaction kinetics of multi-phase systems or simply to measure diffusion coefficients for various applications, e.g., mineral rheology or diffusion chronometry. Some of my current projects are: Pulsed Laser Deposition of silicate thin films and its application to volume and grain boundary diffusion experiments Experimental investigation and modeling of diffusive fractionation of isotopes and elements Thermodynamic modeling of element partitioning between plagioclase and melt Experimental and theoretical studies of diffusion and partitioning behavior of Li in olivine Diffusion modeling of chemical zoning in primitive meteorites to extract cooling rates and identify oxidation events in the solar nebula Modeling of chemical zoning in phenocrysts to determine time scales of magma recharging events Current scientific collaborations: International Katharina Marquardt, Imperial College London, Department of Materials, London, UK Paul Baral, Michaël Coulombier, Hosni Idrissi, Institute of Mechanics, Materials and Civil Engineering (IMMC), Louvain‐la‐Neuve, Belgium Patrick Cordier, Univ. Lille, Unité Matériaux et Transformations, France Corentin Le Guillou, Unité Matériaux et Transformations, Université de Lille, France National Tomoo Katsura, Hongzhan Fei, Lin Wang, Bayerisches Geoinstitut, Bayreuth Horst Marschall, Institut für Geowissenschaften, Universität Frankfurt Harald Behrens, Martin Oeser, Stefan Weyer, Institut für Mineralogie, Universität Hannover Publication List Selected recent publications Baral, P., Orekhov, A, Dohmen, R, Coulombier, M, Raskin, JP, Cordier, P, Idrissi, H, Pardoen, T (2021) Rheology of amorphous olivine thin films characterized by nanoindentation. Acta Materialia, 219, Article Number 117257, DOI 10.1016/j.actamat.2021.117257 Polednia, J, Dohmen, R, Marquardt, K (2020) Grain boundary diffusion and its relation to segregation of multiple elements in yttrium aluminum garnet. Eur J Mineral 32, 675-696 DOI 10.5194/ejm-32-675-2020 Dohmen R, Marschall HR, Ludwig T, Polednia J (2019) Diffusion of Zr, Hf, Nb and Ta in rutile: effects of temperature, oxygen fugacity, and doping level, and relation to rutile point defect chemistry. Phys. Chem. Minerals, 46, 311-332 Ellis BS, Szymanowski D, Magna T, Neukampf J, Dohmen, R, Bachmann, O, Ulmer P, Guillong M (2018) Post-eruptive mobility of lithium in volcanic rocks. Nature Communications 9, Article Number 3228, DOI10.1038/s41467-018-05688-2 Dohmen R, Faak K, Blundy JD (2017) Chronometry and Speedometry of Magmatic Processes using Chemical Diffusion in Olivine, Plagioclase and Pyroxenes. Reviews in Mineralogy & Geochemistry, 83, 535-575 Dohmen R, Ter Heege J, Becker H-W, Chakraborty S (2016) Fe-Mg interdiffusion in orthopyroxene. Am Mineral 101, 2210-2221. Jonas L, Mueller T, Dohmen R, Baumgartner L, Putlitz B (2015) Transport-controlled hydrothermal replacement of calcite by Mg-carbonates. Geology 43, 779-782. Oeser M, Dohmen R, Horn I, Schuth S, Weyer S (2015) Processes and time scales of magmatic evolution as revealed by Fe-Mg chemical and isotopic zoning in natural olivines. Geochim. Cosmochim. Acta. 154, 130-150. Le Guillou C, Dohmen R, Rogalla D, Mueller T, Vollmer C, Becker H-W (2015) New experimental approach to study aqueous alteration of amorphous silicates at low reaction rates. Chem. Geol. 412, 179–192. von Strandmann PAEP, Dohmen R, Marschall HR, Schumacher JC, Elliott T (2015) Extreme Magnesium Isotope Fractionation at Outcrop Scale Records the Mechanism and Rate at which Reaction Fronts Advance. J. Petrol. 56, 33-58. Dohmen R, Blundy J (2014) A predictive thermodynamic model for element partitioning between plagioclase and melt as a function of pressure, temperature and composition. Am. J. Sci., 314, 1319-1372. Marschall HR, Dohmen R, Ludwig T (2013) Diffusion-induced fractionation of niobium and tantalum during continental crust formation. Earth. Planet. Sci. Lett. 375, 361-371. Saunders K, Blundy J, Dohmen R, Cashman K (2012) Linking petrology and seismology at an active volcano. Science 336, 1023-1027. Dohmen R, Milke R (2010) Diffusion in Polycrystalline Materials: Grain Boundaries, Mathematical Models, and Experimental Data. In: Diffusion in Minerals and Melts. Rev. Mineral. Geochem. 72, 921-970. Dohmen R, Kasemann S, Coogan L, Chakraborty S. (2010) Diffusion of Li in olivine. Part I: Experimental observations and a multi species diffusion model. Geochim. Cosmochim. Acta 74, 274-292. Dohmen R, Chakraborty S (2007) Fe-Mg diffusion in olivine II: Point defect chemistry, diffusion mechanisms and a model for calculation of diffusion coefficients in natural olivine. Phys Chem Minerals 34, 409–430. Teaching Wintersemester 176305 Polarisationsmikroskopie I BSc-Level (3. Semester): Dohmen 176504 Polarisationsmikroskopie II BSc-Level (5. Semester): Dohmen Sommersemester 176107 Sicherheit in Gelände und Labor Chakraborty, Sumit; Fockenberg, Thomas; Schuth, Stephan; Dohmen, Ralf; Duda, Mandy Education 1999 – Dr. rer. nat. Degree, University of Cologne Dissertation: Gas phase as a mediator for solid-solid reactions: Knudsen cell mass spectrometry experiments and a thermodynamic kinetic modelling 1996 – Physics Diploma, University of Cologne Thesis: Development of a computer control of a Knudsen cell mass spectrometer to investigate element fractionations in the Solar Nebula Positions held 04/2010 - present: Research Associate Institute for Geology, Mineralogy and Geophysics, Ruhr-University Bochum 02/2009 - 03/2010: Research Associate Dept. of Earth Sciences, University of Bristol, United Kingdom 12/1999 - 01/2009: Research Associate Institute for Geology, Mineralogy and Geophysics, Ruhr-University Bochum 02/1996 - 10/1999: Research Assistant Institute for Mineralogy and Geochemistry, University to Cologne Academic honours 1999 Best Paper published in 1998 in American Mineralogist award, Mineralogical Society of America Das könnte Sie auch interessieren DFG Forschergruppe 2881 Diffusion Chronometry of magmatic systems Geological processes occur in and on the Earth over a range of timescales that form a nested, hierarchical structure. 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DFG Forschergruppe 2881 Diffusion Chronometry of magmatic systems Geological processes occur in and on the Earth over a range of timescales that form a nested, hierarchical structure. Determining the durations of processes that occur on the shorter end of this time-spectrum has been a challenge. The tools of diffusion chronometry have emerged as a very promising method to provide solutions in many situations. The Forschergruppe
Physico-chemical Mineralogy Prof. Sumit Chakraborty Experiments, theory and field studies to understand timescales and mechanisms of geochemical and cosmochemical processes. Atomistic mechanisms of flow and creep. Diffusion controlled processes in Materials Science problems. mehr erfahren Prof. Sumit Chakraborty
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