Mechanics of pegmatite vein emplacement in the lower crust of the Lofoten Islands

Magma transport and emplacement in the Earth’s crust involve the deformation of the host rock to accommodate the influx of magma. Mechanical models of emplacement of planar igneous intrusions, such as dykes and pegmatite veins, assume dominant elastic bending of the host rock, even in the mid-to-lower crust.

However, at the Lofoten islands, field observations of pegmatite veins emplaced in the deep crust evidence that ductile deformation of the host rock plays a major role during the emplacement of the veins, strongly questioning the relevance of the established theory. Revealing the mechanisms of deep magma emplacement thus requires proper documentation and characterization of the modes of deformation of the host rock in response to the influx of the pegmatitic liquids.

The aim of this MSc project is to characterize and reveal the modes of deformation of the host rock that accommodated the emplacement of pegmatitic veins in the deep crust. Well-exposed veins have been identified at Å, and the southwestern tip of the Lofoten islands, while other pegmatite veins in the area can be discovered.

The main scientific objectives of the project are to (1) map in detail the morphology of the pegmatite veins, (2) map structures in the host rock in the near vicinity of the veins, (3) characterize the deformation mechanisms of the host rock and (4) correlate the morphological features of the veins with the deformation structures in the host rock.

The project will integrate the following tasks:

  • Fieldwork in the Lofoten islands;
  • Detailed structural mapping of pegmatite veins;
  • Morphological analysis of the pegmatite veins;
  • Microstructural analysis of rock samples using SEM and EBSD;
  • Correlation between the morphology of the veins and the deformation mechanisms of the host rock.

The learning outcomes of the project are the following:

  • Fieldwork and structural field mapping;
  • Microstructural analysis on thin sections;
  • Ductile rock mechanics;
  • Advanced analytical techniques (SEM, EBSD)

To implement this project, it is recommended to have:

  • Knowledge in structural geology
Published Sep. 7, 2021 12:33 PM - Last modified Sep. 7, 2021 12:33 PM

Scope (credits)