Magma formation and evolution in the western South Aegean Volcanic Arc: Implications for crustal growth and arc migration

• Applicant: Professor Dr. Karsten Matthias Haase
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 534818895

Subduction zones like the Aegean arc typically show extensive magmatic activity including explosive volcanic eruptions and intrusion of large plutons contributing to the growth of the continental crust. The magmas a highly variable in composition ranging from mafic to felsic and from low-K calc-alkaline to shoshonitic series. The formation of these magmas in space and time, the relationship between mafic and felsic melts, and the relation of tectonic and magmatic processes are poorly understood. Here we suggest to test several hypotheses of magma formation in the Aegean arc: (1) different parental magmas in the Aegean form at different times reflecting variable sediment subduction, (2) magmas form in diapiric structures possibly by decompression melting, (3) fractional crystallization including assimilation occurs at different crustal levels, and (4) felsic rocks are closely related to associated mafic rocks from the mantle. Lava samples from selected magmatic centres in the Aegean arc from NE Greece, Samothraki, Limnos, Samos, Pausanias and Milos will be stueied. By defining the composition of primitive low-K calc-alkaline to shoshonitic magmas we will be able to model the succession of mixing and melting processes in the mantle causing their formation and to compare the compositions to those of experimental work in order to define temperature and pressure. Studies of olivine, clinopyroxene and amphibole in the lavas will provide insight into the composition of primitive magmas, the depths of stagnation, and the successive assimilation processes during ascent. Geochronological studies of volcanic rocks in NE Greece and in the younger Aegean arc will help to define the migration of magmatic activity and the evolution between different magma series.

• DFG Programme: Research Grants