International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

The Odivelas Limestone: evidence for a Middle Devonian reef system in western Ossa-Morena Zone (Portugal)

Pages: 121 - 137

Authors: GIL MACHADO, JINDRICH HLADIL, LEONA KOPTIKOVA, PAULO E. FONSECA, FERNANDO T. ROCHA, ARNOST GALLE

Abstract: The Odivelas Limestone constitutes one of the few records of Middle Devonian sedimentation in the western Ossa-Morena Zone. Although deformed and metamorphosed the limestones have an abundant fossil content which allows their positioning as late Eifelian/early Givetian in age and to relate the reef fauna with the typical Rhenish facies for the same time period. Magnetic susceptibility analysis was attempted and is in agreement with the biostratigraphy, but the limited extent of sections and the metamorphism precludes firm correlations. The field evidence, petrographic and geochemical analysis point to a close paleogeographical relation and dependence of the reef system on volcanic structures which are included in the Beja Igneous Complex. The age of part of the volcanic and sub-volcanic suite of this complex is thus constrained.

Keywords: Eifelian/Givetian, Paleozoic orogens, Ossa Morena Zone, Beja Igneous Complex, biostratigraphy, reef fauna, carbonate petrology, magnetic susceptibility

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