Lower crustal fault surfaces

In this project, you will focus on fault surfaces in lower crustal rocks from Lofoten, Northern Norway. Earthquakes in the lower crust of Lofoten produced frictional melts, which solidified to form dark, fine-grained fault rocks called pseudotachylyte.

You will characterize the topography and mineralogy of the interface between the host and the pseudotachylyte (the fault surface) with different techniques such as X-ray microtomography and scanning electron microscopy. Fault roughness has been used to determine whether movement on the fault was fast (earthquakes) or slow (creep); however, this has mainly been done for upper crustal faults, where confining pressure, mineralogy, and fluid content may be significantly different than in the lower crust.

Depending on your interests, you could also investigate the differences in the behaviour of different minerals along the fault surface using electron microscopy. Different minerals have different melting points, but they may not always be relevant in such fast processes. Other properties of the minerals, such as fracture toughness, might be more important.

This project will introduce you to a number of high-end analytical techniques, and provide you with insights into science at the intersection of geomechanics and structural geology (and petrology).

Published Sep. 5, 2022 1:22 PM - Last modified Sep. 5, 2022 1:22 PM

Scope (credits)