Estratigrafía y análisis de facies del Terciario de Melilla

• Autores: David Gómez-Gras, A. Pineda
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 5, 2003 (Ejemplar dedicado a: V Congreso del Grupo Español del Terciario (Granada, 23-25 de septiembre, 2003)), págs. 103-107
• Idioma: inglés
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• Resumen

  • We describe the stratigraphic units and the general facies patterns of the Tertiary succession of the territory of the Ciudad Autonoma de Melilla, and correlate them with the cronostratigraphic units established in the remainder of the Melilla basin in order to assign an age to these units, l/l/e define three new stratigraphic units. The lower carbonate unit is composed of two subunits. The lower reefal subunit is constituted by Porites coral-colonies (boundstones) with well-developed reef-core and reef-slope facies. These reef facies are very similar to the Mediterranean Messinian coral mounds. Overlying and adapting this reefal subunit there is a bioelastic carbonate subunit, mainly composed of molluscan packstones/grainstones including red algae. Bedding in this subunit shows large sigmoid patterns, indicating westward progradation of a bioclastic limestone platform. Then follows an intermediate detrital unit, that consists of yellow, fine-grained siliciclastic sandstones deposited in a prograding deltaic system that filled paleotopographic depressions. The upper carbonate unit unconformably rests upon the previous two, and is composed of oolitic packstones/grainstones and stromatolitic boundstones deposited in a shallow platform. To the SIA/, the whole succession changes into volcaniclastics sediments near the Gourougou volcanic complex. The similarity of the facies of the three stratigraphic units defined and the cronoestratigraphic units described in the Melilla basin permits to assign a Messinian age to the whole succession at the Melilla territory