FOR 2881:  Diffusion Chronometry of magmatic systems

• Subject Area: Geosciences
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 405665352

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. High temperature magmatic systems provide an excellent natural laboratory for developing and calibrating these tools because various kinds of observations from monitoring volcanoes are able to provide cross checks on the results. Subsequently, the newly developed and refined tools may then be applied to a much wider range of geological and planetary settings. This project aims to bring together field geologists, experimental scientists, theoreticians and modellers from geosciences as well as neighbouring fields of physics and materials science to advance this development. Some of the main objectives of the first phase of the proposal for this research unit are: the measurement of missing diffusion parameters in pyroxenes and plagioclase, exploring the recently discovered role of isotopic fractionation at high temperatures due to diffusion, calibrating phase relations to enable the setting of boundary and initial conditions in high resolution diffusion models, exploring the role of textural evolution, and field tests in a divergent as well as at a convergent plate margin magmatic setting (Oman and Kamchatka, respectively).These will be accompanied by the development of user-friendly codes that incorporate the advances. The software would be distributed to the general community free of cost. Future plans include extension to more complex magmatic (e.g. explosive, caldera forming events) and melt-fluid- rock systems (migmatites, mantle metasomatism, ore formation). These would necessitate studies of diffusion in more complex minerals and polycrystalline systems (e.g. amphiboles, micas, water-bearing systems).

• DFG Programme: Research Units
• International Connection: United Kingdom

Projects

• Application of phase-field simulation of solidification and texture evolution to diffusion chronometry (Applicant Kundin, Julia )
• Chronometry in plutonic rocks: cooling rates of ancient oceanic crust (Applicants Faak, Kathrin ;  Kirchenbaur, Maria )
• Coordination Funds (Applicant Chakraborty, Ph.D., Sumit )
• Diffusion-driven Fe-Mg and Li isotope fractionation in olivine: An experimental investigation and new modeling approach (Applicants Dohmen, Ralf ;  Weyer, Ph.D., Stefan )
• Diffusion in common mineral phases. Part 1: pyroxene (Applicants Behrens, Harald ;  Dohmen, Ralf )
• Diffusion in common mineral phases. Part 2: plagioclase. (Applicants Behrens, Harald ;  Dohmen, Ralf )
• Phase stability fields in calc-alkaline magmatic systems and textural evolution of crystalline aggregates (Applicants Chakraborty, Ph.D., Sumit ;  Holtz, Ph.D., Francois )
• User friendly codes for the generalized application of diffusion chronometry (Applicant Chakraborty, Ph.D., Sumit )

• Spokesperson: Professor Dr. Sumit Chakraborty, Ph.D.