Dr. Sebastian Kommescher

Research Profile

I am studying the fluxes of fluid-mobile elements during subduction-related processes. Specifically, I examine the distribution of boron and its isotopes in particular, as it has been proven to be a powerful tracer during fluid-mediated processes.

I take advantage of the experimental petrology facilities at Leibniz University Hannover (LUH) to simulate the conditions in subduction zones under controlled conditions. I make use of the analytical facilities at the Leibniz Universität Hannover, that provide a laser ablation system coupled to a multi-collector mass spectrometer which allows in-situ measurements of stable isotopes. We not only use this possibility to measure boron isotope variations that are difficult to determine through classical geochemical separation, but also continue work on titanium isotope variations in various terrestrial settings - a topic that builds on work from my Ph.D.

Current Projects

• Boron isotope fractionation during fluid exsolution from arc basalts at magmatic temperatures (Project FO 698/10-1, funded until 2023)

Collaborations:

• Dr. Tomáš Magna (Czech Geological Survey)
• Dr. Marc-Alban Millet (School of Earth and Environmental Sciences Cardiff University)

Recent Publications

Kommescher, S., Fonseca, R. O. C., Kurzweil, F., Thiemens, M. M., Münker, C., & Sprung, P. (2020). Unravelling lunar mantle source processes via the Ti isotope composition of lunar basalts. Geochemical Perspectives Letters, 13–18. https://doi.org/10.7185/geochemlet.2007

Rzehak, L. J. A., Kommescher, S., Kurzweil, F., Sprung, P., Leitzke, F. P., & Fonseca, R. O. C. (2021). The redox dependence of titanium isotope fractionation in synthetic Ti-rich lunar melts. Contributions to Mineralogy and Petrology, 176(3), 19. https://doi.org/10.1007/s00410-020-01769-y

Education

• 2008-2011 B.Sc. in Geological sciences, FU Berlin
• 2011-2014 M.Sc. in Geological sciences, FU Berlin
• 2016-2020 Dr. rer. nat. in Mineralogy, Universität zu Köln, Institut für Geologie und Mineralogie. Dissertation: Mass-dependent titanium isotope variations in terrestrial and extra-terrestrial basalts

Positions

• 09/2020 – now
  Postdoctoral researcher, Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Germany (office address: Leibniz Universität Hannover, Institut für Mineralogie, Callinstr. 3, 30167 Hannover; Building 2511, Room 215, Phone: +49-(0)511-762 5974)