Costras carbonatadas en la sucesión aluvial distal eocena de la Formación Hamada de Boudenib II al sur del Alto Atlas (Marruecos)

• Armenteros, I. ^[1] ; Ben Brahim, M. ^[2] ; Blanco, J.A. ^[1] ; Huerta, P. ^[1] ; Suárez, M. ^[1]
  1. [1] Universidad de Salamanca

     Universidad de Salamanca

     Salamanca, España

     
  2. [2] Mohammed 1st University, Marruecos
• Localización: Geogaceta, ISSN 0213-683X, Nº. 34, 2003, págs. 199-202
• Idioma: español
• Títulos paralelos:
  • Calcretes and dolocretes in the Eocene alluvial distal plain succession oi the Hamada de Boudenib II Formation (southern High Atlas Mountains. Morocco)
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• Resumen

  • On the southern edge of the High Atlas Mountains of Morocco, the Tertiary continental deposits form extensive tablelands, the so-called "Hamada", in the Boudenib area. Two units have been defined in the Paleogene: a Lower unit "Hamada de Boudenib I" (lower Eocene) and an Upper one "Hamada de Boudenib II" of Middle/Upper Eocene age. This latter lies unconformably and covers most of the Lower unit; generally dips towards the south and thickens in this same direction. Their central basin deposits essentially consist of mudstones and sandy mudstones, deposited in distal areas (alluvial plain) of alluvial fans with sparse channels and ephemeral carbonate ponding. Intense processes of crust formation produced several facies of calcretes and dolocretes and the ubiquitous palygorskite. The duricrust features indicate that they were formed by continuous processes of carbonate precipitation in the vadose and capillary zones of soil profiles, developed on the alluvial plain, with alternative wetting and drying episodes in a semiarid climate.