Influence of décollement friction on anisotropy of magnetic susceptibility in a fold-and-thrust belt model

Thorben Schöfisch, Hemin Koyi, Bjarne Almqvist

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Anisotropy of magnetic susceptibility can provide insights into strain distribution in models simulating fold-and-thrust belts. Models with layers of sand and magnetite mixture shortened above adjacent décollements with high and low friction, are used to study the effect of décollement friction on the magnetic fabric. Above high-friction décollement, an imbricate stack produced a ‘tectonic’ fabric with magnetic foliation parallel to thrusts. In contrast, above the low-friction décollement deformation propagated farther into the foreland, and deformation intensity is gradual from the foreland to the hinterland by defining a transition zone in between. In this zone, magnetic lineation rotated parallel to the deformation front, whereas in the hinterland the principal axes do not show a preferred orientation due to different deformation mechanisms between “thrust-affected” and “penetrative-strain affected” area. Above both décollement types, the principal axes of susceptibility developed tighter clustering with depth. Along the boundary between the two décollements, a deflection zone formed where rotation of surface markers and magnetic fabric reflect the transition between structures formed above the different décollements. Through quantifying magnetic fabric, this study reemphasises the clear link between décollement friction, strain distribution and magnitude in fold-and-thrust belts.

Original languageBritish English
Article number104274
JournalJournal of Structural Geology
Volume144
DOIs
StatePublished - Mar 2021

Keywords

  • Analogue modelling
  • Anisotropy of magnetic susceptibility
  • Basal friction
  • Décollement
  • Fold-and-thrust belt

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