The Modern and Ancient Pattern of Sandflow through the Southern Namib Deflation Basin

  1. K. Pye2 and
  2. N. Lancaster3
  1. I. Corbett

Published Online: 8 APR 2009

DOI: 10.1002/9781444303971.ch4

Aeolian Sediments: Ancient and Modern

Aeolian Sediments: Ancient and Modern

How to Cite

Corbett, I. (1993) The Modern and Ancient Pattern of Sandflow through the Southern Namib Deflation Basin, in Aeolian Sediments: Ancient and Modern (eds K. Pye and N. Lancaster), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303971.ch4

Editor Information

  1. 2

    Reading, UK

  2. 3

    Reno, Nevada, USA

Author Information

  1. Department of Geology, University of Cape Town, Rondebosch 7700, South Africa

Publication History

  1. Published Online: 8 APR 2009
  2. Published Print: 27 MAY 1993

ISBN Information

Print ISBN: 9780632035441

Online ISBN: 9781444303971



  • sandflow modern and ancient pattern in southern Namib deflation basin;
  • yardang distribution formed from Precambrian dolomite and aeolian transport corridors;
  • morphology of southern Namib deflation basin;
  • surface windflow pattern;
  • coastal sediment entry points and barchan dune trains;
  • spatial sandflow variation;
  • displacement of aeolian transport corridors;
  • sea level movement on deflation basin dynamics and sand sea maintenance;
  • Fiskus sandstone bed cut and southern Namib deflation basin shift


The aeolian system within the 0–20 km wide coastal tract of the southern Namib deflation basin is governed by unimodal southwesterly to south-southeasterly surface windflow. A strong seasonality characterizes the wind energy of the system, with the peak occurring from September to March, when gusting at 80–100 km h−1 is common.

Despite the high energy of the aeolian system, beach deflation supplying sediment to the aeolian system is restricted to log-spiral and south-facing re-entrant embayments, along the otherwise exposed Atlantic coastline. Sand trap data from a traverse perpendicular to sandflow some 30 km downwind of one such point source prove that rather than fanning out, the sandflow remains within a 1–2 km wide linear, wind-parallel zone. This zone and other similar linear zones are delineated by barchan dune trains which extend up to 120 km from the coast to the Namib Sand Sea. The high-sandflow zones thus act as aeolian transport corridors, in which optimal conditions for aeolian creep transport occur. The possible existence of longitudinal vortices within the planetary boundary layer above the deflation basin provides one mechanism by which the corridors might be maintained.

The distribution of yardangs formed from Precambrian dolomite on the floor of the present-day deflation basin supports the conclusion that the position of aeolian transport corridors has varied with time. Palaeoyardang surfaces, lying outside the present aeolian transport corridors, are undergoing modification by solution weathering. These features must, however, have previously lain within the path of an aeolian transport corridor generated from a regressive coastline. Thus the distribution of aeolian transport corridors has been, and still is, governed by coastal morphology, which is a function of sea level fluctuation and deflation basin morphology. Changes of this sort provide a key to understanding the periodic expansion and contraction of the post-Miocene sand sea, as evidenced by the ongoing formation of erosional, regional bounding surfaces.