We are pleased to welcome Sarah Incel to our Petrology Lunch, who will be speaking on the topic of: Hydration and deformation of the lower continental crust.

Abstract:

Plagioclase minerals represent the most common mineral group of Earth’s lower continental crust. Yet, experimental data on their deformation behaviour at comparable pressure and temperature conditions, prevailing at lower crustal depths, are scarce. The few existing quantitative data on plagioclase deformation favour the model of a weak lower continental crust sandwiched between two strong layers – the upper crust and the upper mantle. However, due to the record of lower crustal earthquakes, e.g., below the Tibetan plateau, and pseudotachylyte veins found in lower crustal rocks, e.g., in SW and N Norway, the lower continental crust could be much stronger than expected. Due to the mechanical coupling between the lithospheric layers, deciphering the deformation behaviour of lower crustal rocks is not only of importance to unravel the puzzling nature of lower crustal earthquakes but also of tremendous importance to better understand the complex deformation of Earth’s lithosphere as a whole. Throughout the past 5 years, Sarah has experimentally investigated the deformation behaviour of plagioclase-rich rocks with the focus on highlighting the influence of fluid-rock interactions at eclogite-facies conditions on their deformation behaviour. This impact of fluids on the deformation behaviour of plagioclase-rich rocks under eclogite-facies conditions will be the centre of this presentation. Further, some current research on the development of a deformation twin-based piezometer for plagioclase will be shown – a potential tool to estimate paleo-stresses in plagioclase-rich rocks.

For Zoom access:

Meeting ID: 977 6770 1874

Passcode: 090420