Research
Granulite facies metamorphism – Crustal melting and mineral textures
Granulite facies rocks offer crucial insights into the thermal and chemical evolution of the middle-lower continental crust. Found in various orogenic belts, these rocks exhibit diverse P-T conditions and chemical compositions. Their typical mineral assemblage includes dry phases like garnet or pyroxene, with hydrous phases being rare. This suggests low H2O content, often resulting from metamorphism of initially water-saturated protoliths. The lack of an aqueous fluid/melt phase can preserve local disequilibria, seen in mineral textures. Understanding crustal melting processes, aided by partially melted rocks, helps reconstruct the P-T-X-t history, shedding light on geodynamic evolution and high-grade metamorphism.
REE- and U/Th-bearing accessory minerals – Tiny crystals with big impact
Accessory phases like monazite, xenotime, and allanite play a crucial role as REE carriers in natural rocks, remaining stable across a broad P-T range. In metamorphosed pelitic rocks, monazite is stable from greenschist to granulite facies, making it valuable for studying elemental fractionation during metamorphism and melting. Crystallized melt inclusions, known as nanogranitoids, within minerals like monazite and garnet can provide insights into the geochemical evolution of rocks during crustal melting. Investigating element partitioning in the garnet-monazite-melt system and using geochronology to date melting events offers a deeper understanding of the complex processes involved in high-grade metamorphism.
Early Earth evolution: Archean metamorphism, crustal differentiation and the onset of plate tectonics
This research focuses on understanding the early evolution of the Earth, particularly during the Archean eon, through the study of metamorphic and igneous rocks from southwest Greenland. Key areas of investigation include determining the nature, age, and tectonic setting of metamorphism affecting the Isua Supracrustal Belt, as well as understanding the processes that led to the development of the modern felsic crust. Dating methods, such as Sm-Nd, Lu-Hf and U-Pb isotopic systems, alongside thermobarometric calculations and thermodynamic modeling, are employed to trace the pressure-temperature-time evolution of the rocks. Additionally, the study of garnet growth zones and accessory minerals like monazite and zircon helps to provide insights into the distribution of trace elements and further refine the geochronological framework of early Earth's crustal evolution.
