Timing of subduction exhumation in Syros, Greece

Exploring the exhumation history of the Cycladic Blueschist Unit, Greece using calcite U-Pb dating

The Cycladic Blueschist unit exposed in the Greek islands is well-known for its spectacular high-pressure blueschist and eclogitic assemblages. These rocks preserve an exceptional record of the subduction and exhumation history of remnants of the Jurassic aged Tethys Ocean during the Eocene. These rocks are the perfect location to explore the deformation processes preserved within a fossilised subduction zone. The meta-sediments and meta-ophiolites exposed in the Cyclades, metamorphosed to blueschist and eclogite facies conditions, record both the early high pressure metamorphic and the later extensional exhumation history during Miocene mountain building events.

Brittle transpressional and transtensional deformation fabrics and structures have overprinted the earlier ductile fabrics since the Miocene, meaning the Cyclades preserve a complex structural history spanning both deep and shallow crustal processes. The retrograde overprinting and exhumation history of these complexly deformed rocks remains a topic of considerable debate. Emerging techniques have been developed for directly-dating structures using calcite, a mineral ubiquitous in many brittlely deformed rocks, and have opened up a whole new realm of tectonic investigation in the upper crust.

This project will utilise and help develop this cutting-edge technique in order to unravel timing of exhumation and brittle overprinting within the carbonate assemblages (perfect for calcite U-Pb dating) exposed in the Greek Cyclades. This project will involve fieldwork in the Greek islands to collect suitable calcite samples, which once characterised, will be analysed in the state-of-the-art geochronology laboratories at the University. This represents an exciting opportunity to apply a new method to better understand the timing and rates of exhumation of deep crustal rocks during mountain building