Fossil assemblages and biostratigraphy of metamorphic rocks of the Nevado-Filábride Complex from the Águilar tectonic arc (SE Spain)

Abstract

Abundant marine macrofossils are present in graphitic marbles and calc-silicate schists belonging to the Veleta nappe of the Nevado-Filábride Complex (Internal Zones of the Betic Cordillera, SE Spain), in what is called the Águilas tectonic arc. These fossils have resisted metamorphism and deformation, and in some instances have been finely preserved. The fossil assemblages are dominated by crinoids, followed by minor cephalopods, brachiopods, rugose corals, and putative sections of trilobites. In addition to these confidently identified groups, there are other fossil represented, but deformation and extensive recrystallization have destroyed anatomical characters, hampering their taxonomic identification. Among the crinoids, the columnal parataxa Pentagonopentagonalis (col.) and Bystrowicrinus (col.) have been recognized. Planispiral cephalopods assigned to either primitive ammonoids attributable to the order Agniatitid (one of them being a possible member of the family Mimosphinctidae) or coiled nautilids, as well as orthoconid sections of possible orthoceratids or bactritids are present. Finally, there are rugose coral attributable to the family Phillipsastreidae, possibly Peneckiella. Among the remains with obscure taxonomic assignment, we recognize possible laminar calcareous algae an benthic foraminifers Finally, irregular, massive structures showing a rough laminar organization and longitudinal tubes with rounded sections are found in some black marble beds. These can be identified either as possible chaetetids or bryozoans. The report of these taxa has limited the rocks studied to the Emsian, late Early Devonian