Interpretation of Bedding Geometry within Ancient Point-Bar Deposits

  1. M. Marzo and
  2. C. Puigdefábregas
  1. B. J. Willis

Published Online: 14 APR 2009

DOI: 10.1002/9781444303995.ch9

Alluvial Sedimentation

Alluvial Sedimentation

How to Cite

Willis, B. J. (1993) Interpretation of Bedding Geometry within Ancient Point-Bar Deposits, in Alluvial Sedimentation (eds M. Marzo and C. Puigdefábregas), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303995.ch9

Editor Information

  1. Barcelona, Spain

Author Information

  1. Department of Geological Sciences, State University of New York at Binghamton, Binghamton, NY 13901, USA

  1. Bureau of Economic Geology, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-7508, USA

Publication History

  1. Published Online: 14 APR 2009
  2. Published Print: 16 SEP 1993

ISBN Information

Print ISBN: 9780632035458

Online ISBN: 9781444303995



  • bedding geometry within ancient point bar deposits;
  • production and migration of Synthetic deposits;
  • palaeochannel deposits (storeys);
  • deposit thickness, bedding geometry, grain size variation, palaeocurrent orientations;
  • Higher in the storey planar-stratification;
  • small-scale cross-stratification;
  • super imposition over sediments due to chute cutoff


Few ancient river-channel deposits have been described in enough detail to allow interpretation of channel-bar geometry and migration. Such interpretations require an understanding of the interaction between the style of channel migration, temporal and spatial variation in channel-bar geometry and facies, and outcrop orientation. This interaction is modelled with the aid of a computer model which predicts thickness, bedding geometry, grain size and palaeocurrent orientations of deposits formed by a migrating, curved alluvial channel segment. Computer simulations are compared with several well-described ancient point-bar deposits. These comparisons suggest that bedding geometry and sedimentary characteristics observed in outcrops can be interpreted in terms of specific cross-sections through migrating channel bends of prescribed geometry and hydraulics.