Professor Mark Anderson (University of Plymouth, SoGEES) – Contact me
Professor Luca Menegon, Department of Geosciences, University of Oslo
Dr Nick Roberts, British Geological Survey
Professor Jamie Wilkinson, Natural History Museum
How does the base of a mountain belt deform and localize large earthquakes? Does it represent a preferential conduit for fluid flow in the Earth’s crust? This PhD project will address these questions using a continuous 2.4km section of core drilled through the base (décollement) of the Caledonian mountain belt as part of the International Continental Drilling Programme project “Collisional Orogeny in the Scandinavian Caledonides” (COSC-2) . The core represents a unique opportunity to examine the role of fluids in facilitating deformation in the lower plate during continental collision , sections of the continental crust that are inaccessible in areas of active continental collision because they are deeply buried. The results will be used to critically re-evaluate mechanical models for lower plate deformation in active mountain belts and implications for better modelling of seismic hazard in these settings .
Mineral veins represent proxies for fluid flow during deformation. Microstructural and petrographic analyses of vein samples and associated alteration will determine the spatial distribution, relative timing and mechanism of vein forming processes throughout the core-section. U-Pb geochronology (using laser ablation inductively coupled plasma mass spectrometry) and fluid inclusion studies will constrain the vein chronology and the pressure, temperature and composition (including isotopic composition) of vein-forming fluids . Together the data will be used to evaluate the role of fluids in relation to slip on thrust faults within both ancient and modern décollements.
The successful candidate will be part of a large international collaborative research team working under the wider remit of COSC-2. Training will be given in structural analysis of drill core (using state-of-the art logging tools), electron microscopy/microprobe analysis, electron backscatter diffraction, U-Pb geochronology and fluid inclusion analysis. The student will develop expertise in each method and their application to understanding how geological fluids influence deformation. Training will also be given in communication of research results and how these can be integrated with geophysical models for seismicity in active collisional settings .
Candidates should have a degree in Earth Sciences/Geology or similar. Desirable experience includes structural geology, geochemistry, plate tectonics and natural hazards.