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Lessons Learned from Electron Microscopy of Deformed Opalinus Clay

  • Ben LaurichEmail author
  • Janos L. Urai
  • Guillaume Desbois
  • Jop Klaver
  • Christian Vollmer
  • Christophe Nussbaum
Conference paper
Part of the Springer Series in Geomechanics and Geoengineering book series (SSGG)

Abstract

Using a combined approach of ion-beam milling and electron microscopy, we observe, describe and quantify the microstructure of naturally and synthetically deformed Opalinus Clay (OPA) and deduce its microstructural evolution and underlying deformation mechanisms. The investigated samples derive from the so-called Main Fault, a 10 m offset fold-bend thrust fault crossing the Mont Terri Rock Laboratory in the Swiss Jura Mountains. The samples are slightly overconsolidated, experienced a burial depth of 1350 m and a maximum temperature of 55 °C. Most impact on strain is attributed to frictional sliding and rigid body rotation. However, trans-granular fracturing, dissolution-precipitation of calcite, clay particle neoformation and grain deformation by intracrystalline plasticity have a significant contribution to the fabric evolution. The long-term in-situ deformation behavior of OPA is inferred to be more viscous than measured at laboratory conditions.

Keywords

Shear Zone Clay Particle Accretionary Prism Rigid Body Rotation Rock Laboratory 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Ben Laurich
    • 1
    Email author
  • Janos L. Urai
    • 1
    • 2
  • Guillaume Desbois
    • 2
  • Jop Klaver
    • 2
  • Christian Vollmer
    • 3
  • Christophe Nussbaum
    • 4
  1. 1.Federal Institute for Geosciences and Natural Resources (BGR)HannoverGermany
  2. 2.Structural Geology, Tectonics and GeomechanicsRWTH Aachen UniversityAachenGermany
  3. 3.Institute for MineralogyUniversity MünsterMünsterGermany
  4. 4.Swiss Geological Survey, Federal Office of Topography SwisstopoWabernSwitzerland

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