Timing of formation of Kohistan arc crust: applying the new in situ garnet U–Pb geochronometer

• Applicant: Professor Dr. Horst Marschall
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 578400488

Subduction zones are the most dynamic part of modern plate tectonics and they are the main locus of continental crust formation on Earth. The timescales of crust formation in subduction zones ("island arcs") are crucial for thermal models and for deciphering the connection between deep-crustal processes and the volcanic manifestation of arc magmatism observed on the surface. In this research project we will apply the newly developed U-Pb garnet dating method to the garnet-bearing crustal rocks to the Kohistan Arc, which is arguably the best preserved section of an island arc on Earth. The project aims to decipher the timescales and rates involved in the building of the arc crust. The results will be compared to the set of zircon U–Pb ages from the same section and to the published cooling history established through other geochronometers to enhance our understanding of the behaviour of the U–Pb system in garnet.

• DFG Programme: Research Grants