Formation of Large-Scale Shear Structures during Deposition from High-Density Turbidity Currents, Grès d'Annot Formation, South-East France

  1. William McCaffrey,
  2. Ben Kneller and
  3. Jeff Peakall
  1. J. D. Clark and
  2. D. A. Stanbrook

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304275.ch16

Particulate Gravity Currents

Particulate Gravity Currents

How to Cite

Clark, J. D. and Stanbrook, D. A. (2001) Formation of Large-Scale Shear Structures during Deposition from High-Density Turbidity Currents, Grès d'Annot Formation, South-East France, in Particulate Gravity Currents (eds W. McCaffrey, B. Kneller and J. Peakall), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304275.ch16

Editor Information

  1. School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK

Author Information

  1. Department of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS, UK

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 24 APR 2001

ISBN Information

Print ISBN: 9780632059218

Online ISBN: 9781444304275

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Keywords:

  • field-based approaches;
  • formation of large-scale shear structures during deposition from high-density turbidity currents, Grès d'Annot Formation, south-east France;
  • Grès d'Annot (Annot Sandstone) - part of Eocene–Oligocene succession throughout the Alpine foreland basins;
  • thick-bedded sandstone facies;
  • grain-size distribution;
  • grain orientation relative to palaeocurrent direction;
  • Trois Evêchés outcrop area - comprising amalgamated sheet sandstones with minor channels

Summary

Sedimentary shear structures at the base of thick-bedded graded sandstone beds in the Grès d'Annot turbidite system of south-east France suggest that the deformation was related to the emplacement (transport and deposition) of the overlying thick-bedded sandstones. Examples presented in this chapter from the Trois Evêchés outcrop area, where such structures are well developed, range from rip-up clasts, clastic injection structures, folded beds, recumbent folded strata, and imbricate stacks composed of sandstone beds from the underlying deposits.

Grain fabric analysis presented in this chapter suggests that the transport and deposition process of the overlying sandstones was largely that of a high-density turbidity current. We postulate that high shear stress at the base of flow caused the observed deformation and, locally at the seafloor–sediment interface, rapid flow freezing.