Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway
 

Summary: Applications of inclusion behaviour models to a major shear zone system:
The Nordfjord-Sogn Detachment Zone in western Norway
Fernando O. Marques a,*, Daniel W. Schmid b
, Torgeir B. Andersen b
a
Faculdade de Cie^ncias, Departamento de Geologia and IDL, Universidade Lisboa, Edificio C6, Piso 2, 1749-016 Lisbon, Portugal
b
Physics of Geological Processes, University of Oslo, P.O. Box 1048, Blindern, 0316 Oslo, Norway
Received 10 February 2007; received in revised form 3 May 2007; accepted 15 May 2007
Available online 30 June 2007
Abstract
Rigid inclusion models have reached a stage where one should be able to use them to obtain quantitative values from ductile shear zones. We
used natural data collected in three sites and combined analogue and theoretical modelling to assess vorticity, strain, nature of rigid inclusion/
matrix interface and confinement in the large-scale, ductile Nordfjord-Sogn Detachment Zone (NSDZ) of the Caledonides of western Norway.
Our study shows that: (1) the observed shape preferred orientation (SPO) at higher structural levels of the NSDZ at Site 1, Gjervika, can be
explained by simple shear (pure shear/simple shear ratio Sr ¼ 0) associated with a slipping inclusion/matrix interface. (2) The observed SPO
at deeper structural levels of the NSDZ at Site 2, near Sandane can be produced by simple shear associated with a significant amount of short-
ening across the shear zone (Sr z 1), acting upon rigid inclusions in slipping contact with the enclosing matrix. (3) Observed back rotated bou-
dins deeper in the NSDZ at Site 3, Biskjelneset, can form in confined flow associated with a considerable amount of shortening across the shear
zone (Sr ! 0.4). (4) The observed tails of porphyroclasts indicate a minimum (at least local) strain of ca. g z 20. (5) The clasts in the studied

  

Source: Andersen, Torgeir Bjørge - Centre for Physics of Geological Processes & Department of Geosciences, Universitetet i Oslo

 

Collections: Geosciences