shorelines of the Holocene Megalake Chad (Africa, Sahara) investigated with very high resolution satellite imagery (Pléiades) : example of the Goz Kerki paleo-spit

  • Mathieu Schuster Institut de Physique du Globe de Strasbourg, UMR7516, CNRS – Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex
  • Claude Roquin Institut de Physique du Globe de Strasbourg, UMR7516, CNRS – Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex
  • Abderamane Moussa Département de Géologie et Paléontologie, Faculté des Sciences, Université de N’Djamena
  • Jean-François Ghienne Institut de Physique du Globe de Strasbourg, UMR7516, CNRS – Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex
  • Philippe Duringer Institut de Physique du Globe de Strasbourg, UMR7516, CNRS – Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex
  • Frédéric Bouchette Géosciences-Montpellier CNRS / Université Montpellier II 34095 Montpellier
  • Arnaud Durand SERTIT, Université de Strasbourg, 300 Boulevard Sébastien Brandt, 67412 Illkirch-Graffenstaden
  • Bernard Allenbach SERTIT, Université de Strasbourg, 300 Boulevard Sébastien Brandt, 67412 Illkirch-Graffenstaden

Résumé

Megalake Chad (350,000 km2), the largest paleo-lake of the Sahara-Sahel area, is one of the most emblematic marker of the hydroclimatic changes that occurred during the African Humid Period (AHP; ca. 11,500 – 5,000 years BP) in subtropical Africa. From field surveys, the existence of Megalake Chad is well demonstrated by widespread typical lake deposits. However, considering the very large size of this paleo-lake, it is best evidenced and understood from space. Conspicuous paleo-littoral features distributed along hundreds of kilometers are clearly visible on second generation satellite images. These features represent major archives of the Megalake Chad and of the climate during the AHP. This paper is the first attempt to investigate the paleo-littoral of Megalake Chad with very high resolution satellite imagery. A Pléiades scene (images and DEM) is used to characterize the fossil sand spit of the Goz Kerki, which is one of the most representative and best preserved littoral features of Megalake Chad. Thanks to Pléiades stereoscopic images the geomorphology and the lithology of this paleo-spit can now be detailed and the evolution of the paleo-bathymetry of Megalake Chad can be reconstructed. This brings new insights into the paleo-environments and paleo-climates of the Sahara-Sahel region.

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Publiée
2014-09-05
Comment citer
SCHUSTER, Mathieu et al. shorelines of the Holocene Megalake Chad (Africa, Sahara) investigated with very high resolution satellite imagery (Pléiades) : example of the Goz Kerki paleo-spit. Revue Française de Photogrammétrie et de Télédétection, [S.l.], n. 208, p. 63-68, sep. 2014. ISSN 1768-9791. Disponible à l'adresse : >https://www.sfpt.fr/rfpt/index.php/RFPT/article/view/114>. Date de consultation : 22 nov. 2017
Rubrique
Articles

Mots-clés

african humid period, beach ridges, paleo-lake, littoral