Project description

What is the critical shear stress that activates different slip systems in plagioclase? Can we use mechanical twinning in plagioclase as a paleo piezometer in natural plagioclase-rich rocks?

Our aim is to quantify the critical resolved shear stresses (CRSS) that activate different slip systems of plagioclase. We also want to quantify the critical resolved shear stress for mechanical twinning. Quantifying the stresses required to activate the crystal-plastic deformation of plagioclase is of paramount importance to better understand the deformation of lower crustal rocks, as plagioclase is the most abundant rock-forming mineral in the crust. In addition, quantifying the critical resolved shear stress for twinning can provide an estimate of paleo stresses in natural plagioclase-bearing rocks. To quantify the CRSS of different slip systems, we use a novel experimental approach to test the mechanical behavior of hard materials, called micropillar compression. This technique is mainly used in materials science to test the mechanical behaviour of hard materials, which mainly deform by brittle fracture when deformed in a standard mechanical test setup. By deforming micropillar with a diameter of only a few µm, brittle deformation of the samples is prevented, as the stresses that trigger plastic deformation are expected to be lower than those that generate and propagate cracks. This novel technique has the potential to allow us to study and quantify the plastic deformation of “difficult” materials that either remain largely brittle even under high pressure and high temperature conditions or become unstable under such conditions, e.g. dehydration.

Project duration

2022 -

Funding agencies

NERC Independent Research Fellowship (2022-2024)

Cooperation

RWTH Aachen