Formation of orogen-perpendicular thrusts due to mechanical contrasts in the basal décollement in the Central External Sierras (Southern Pyrenees, Spain)

Oskar Vidal-Royo, Hemin A. Koyi, Josep Anton Muñoz

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Two series of analogue models are used to explore the effect of ductile-frictional contrasts of the basal décollement on the development of oblique and transverse structures during thin-skinned shortening. These models simulate the evolution of the Central External Sierras (CES; Southern Pyrenees, Spain), which constitute the frontal emerging part of the southernmost Pyrenean thrust. The CES are characterised by the presence of N-S to NW-SE anticlines, perpendicular to the Pyrenean structural trend and developed in the hanging-wall of the thrust system. They detach on unevenly distributed Triassic materials (evaporitic-dolomitic interfingering). The models simulated the effect of adjacent ductile versus frictional décollements during shortening. Model Series A tests the thickness ratio between overburden and the ductile layer, whereas model Series B tests the width (perpendicular to the shortening direction) of frictional décollement. Model results confirms that deformation reaches further in areas detached on a ductile layer whereas above frictional décollement areas, shortening is accommodated by additional uplift and penetrative strain. This replicates the structural style of the CES: higher structural relief of N-S anticlines with regard to orogen-parallel structures, absence of a representative ductile décollement in the core, plunging towards the hinterland and foreland-side closure not thrusted by the South Pyrenean thrust.

Original languageBritish English
Pages (from-to)523-539
Number of pages17
JournalJournal of Structural Geology
Volume31
Issue number5
DOIs
StatePublished - May 2009

Keywords

  • Analogue modelling
  • Brittle deformation
  • Detachment
  • Ductile deformation
  • External Sierras
  • Pico del Aguila
  • Southern Pyrenees

Fingerprint

Dive into the research topics of 'Formation of orogen-perpendicular thrusts due to mechanical contrasts in the basal décollement in the Central External Sierras (Southern Pyrenees, Spain)'. Together they form a unique fingerprint.

Cite this