Petrologie und Geochemie

Dr. Ralf Dohmen

Wissenschaftlicher Mitarbeiter
Laborleiter für gepulste Laserabscheidung

Dohmen - Photo
Dr. Ralf Dohmen

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:

  • 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
  • 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

 

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

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