International Journal of Earth Sciences

, Volume 96, Issue 2, pp 229–252 | Cite as

Structural evolution of the contact between two Penninic nappes (Zermatt-Saas zone and Combin zone, Western Alps) and implications for the exhumation mechanism and palaeogeography

  • Jan PleugerEmail author
  • Sybille Roller
  • Jens M. Walter
  • Ekkehard Jansen
  • Nikolaus Froitzheim
Original Paper


The boundary zone between two Penninic nappes, the eclogite-facies to ultrahigh-pressure Zermatt-Saas zone in the footwall and the blueschist-facies Combin zone in the hanging wall, has been interpreted previously as a major normal fault reflecting synorogenic crustal extension. Quartz textures of mylonites from this fault were measured using neutron diffraction. Together with structural field observations, the data allow a refined reconstruction of the kinematic evolution of the Pennine nappes. The main results are: (1) the contact is not a normal fault but a major thrust towards northwest which was only later overprinted by southeast-directed normal faulting; (2) exhumation of the footwall rocks did not occur during crustal extension but during crustal shortening; (3) the Sesia-Dent Blanche nappe system originated from a continental fragment (Cervinia) in the Alpine Tethys ocean, and the Combin zone ophiolites from the ocean basin southeast of Cervinia; (4) out-of-sequence thrusting played a major role in the tectonic evolution of the Penninic nappes.


Alps Tectonics Exhumation Palaeogeography Quartz texture 



This article benefited from comments and suggestions of the reviewers Giancarlo Molli and Neil Mancktelow, which are gratefully acknowledged. Supported by DFG (grant no. FR700/6).


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Jan Pleuger
    • 1
    Email author
  • Sybille Roller
    • 1
  • Jens M. Walter
    • 2
  • Ekkehard Jansen
    • 2
  • Nikolaus Froitzheim
    • 1
  1. 1.Geologisches InstitutUniversität BonnBonnGermany
  2. 2.Mineralogisch-Petrologisches InstitutUniversität BonnJülichGermany

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