Microstructural map of a thin-section scale fold pair; implications for folding mechanism in a fine-grained garnet

  1. Aerden, Dominicus G.A.M.
  2. Aldaher, S.
  3. Bouybaouene, M.
  4. Sayab, M.
Revista:
Trabajos de geología

ISSN: 0474-9588

Año de publicación: 2009

Número: 29

Páginas: 60-63

Tipo: Artículo

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Otras publicaciones en: Trabajos de geología

Resumen

etailed microstructural mapping of thin section-scale folds in a garnet bearing micaschist sample from the RIF Mountains (Morocco), including analysis of inclusion trails in 62 small garnets, reveals interesting details about the folding mechanism. A number of classic fold mechanisms capable of producing axial-plane cleavage are reviewed and shown to insufficiently explain the mapped microstructural patterns including cleavage fanning, wedge-shaped microlithons, and detailed crenulation geometries associated with different stages of compositional differentiation (S2). A new model is proposed in which crenulation cleavage evolves from initial conjugate kink bands to sets of closely spaced micro-shear zones with major shortening components.

Referencias bibliográficas

  • AERDEN, D. G. A. M. (1996): The pyrite-type strain fringes from Lourdes, France: indicators of Alpine thrust kinematics in the Pyrenees. J. Struct. Geol., 18: 75-92.
  • BELL, T. H. (1981): Foliation development – the contribution, geometry and significance of progressive, bulk, inhomogeneous shortening. Tectonophysics, 75: 273-296.
  • GRAY, D. R. and DURNEY, D. W. (1979): Investigations on the mechanical significance of crenulation cleavage. Tectonophysics, 58: 35-80.
  • HOBBS, B. E., MEANS, W. D. and WILLIAMS, P. F. (1982): The relationship between foliation and strain: an experimental investigation. J. Struct. Geol., 4: 411-428.
  • PRICE, N. J. and COSGROVE, J. W. (1990): Analysis of geological structures. Cambridge University Press, 502 pp.
  • TREAGUS, S. H. (1983): A theory of finite strain variation through contrasting layers, and its bearing on cleavage refraction. J. Struct. Geol., 5: 351-368.
  • WILLIAMS, P. F. (1990): Differentiated layering in metamorphic rocks. Earth Sci. Rev., 29: 267-281.
  • WRIGHT, T. O. and HENDERSON, J. R. (1992): Volume loss during cleavage development in the Meguma Group, Nova Scotia, Canada. J. Struct. Geol., 14: 281-290.
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