Sarah Incel – NERC Independent Research Fellow

Project summary

How strong is Earth’s crust? This question is the main motivation behind my NERC Independent Research Fellowship (IRF), funded by UK Research and Innovation. The main goal of my NERC IRF is to estimate stresses in crustal rocks. To do so, I aim to create a new tool, i.e., a piezometer, which will be based on mechanical twinning in plagioclase – the most common mineral group of Earth’s crust. By conducting uniaxial compression tests on micrometre-sized plagioclase-pillars, I will be able to study and quantify the onset of mechanical twinning as well as twin morphology as a function of pillar diameter, plagioclase chemistry, total strain, strain rate, and temperature in situ. Furthermore, I will experimentally study the interplay between cracking and twinning over a broad pressure, temperature, and strain rate range in millimetre-sized plagioclase aggregates using a Paterson gas-medium apparatus installed in the Rock and Mineral Physics Laboratory at the University of Minnesota. The ultimate goal is to apply this new piezometer to natural rocks exhumed from mid to lower crustal depths (approx. 20 to 60 km).

Academic career & research profile

In 2014, I graduated with an M.Sc. in Geology from Freie Universität Berlin. From 2014 to 2017, I was a PhD student at the Ecole Normale Supérieure Paris with Prof Alexandre Schubnel as PhD advisor. In 2017, after receiving my PhD, I obtained a Feodor-Lynen Fellowship, awarded by the Alexander von Humboldt-Foundation, which enabled me to conduct two years of postdoctoral research at the University of Oslo. I continued my postdoctoral research in the Experimental Geophysics Laboratory of Prof Jörg Renner at Ruhr-Universität Bochum from 2019 to 2022. As a NERC Independent Research Fellow, I joined CASC in October 2022.

My research involves the experimental investigation of the deformation behaviour of rocks at high-pressure, high-temperature conditions prevailing at lower crustal depths. Most of my previous research focused on the interplay between deformation and alteration processes in complex materials such as crustal rocks, e.g., natural blueschist and granulite. To investigate the interplay between rock deformation and chemical reactions, I perform chemical and micro- and nanostructural analyses on natural rocks as well as on experimental rock samples. To extrapolate the experimental results to nature, I directly compare the experimental with natural micro- and nanostructures and/or quantify scale-independent processes such as reaction kinetics in the experimental samples.