Lower Devonian stromatoporoids from the northern Obejo-Valsequillo-Puebla de la Reina Domain (Badajoz and Córdoba provinces, Southern Spain)

Abstract

The stromatoporoid fauna from three locations in the “Peñón Cortado Limestone” (Pragian to Upper Emsian) from the area of Quintana de la Serena (Badajoz Province) and Peñarroya-Pueblonuevo (Córdoba Province) in the Obejo-Valsequillo-Puebla de la Reina Domain (Sierra Morena, Southern Spain) were investigated. The 71 stromatoporoid specimens collected belong to 11 different species.

The “Peñón Cortado” section in the Córdoba Province contains two different stromatoporoid-bearing horizons with very different fauna (bed 14 and bed 19b). In the older bed 14 dominates Plectostroma salairicum (Javorskij, 1930), meanwhile in the younger bed 19b Actinostroma compactum Ripper, 1933 and Pseudotrupetostroma anacontentoae May, 2005b dominate. The fauna of the younger bed 19b of the location “Peñón Cortado” correlate well with the stromatoporoid-bearing beds of the locations “Guadámez II” and “La Chamorra” in the Badajoz Province.

The absence of stromatoporoids with branched skeletons and the scarcity of stromatoporoids of the type which forms thin-layered crusts probably inhibited reef development. A possible explanation for this may be a relatively low water temperature.

Biogeographically, the fauna of the Sierra Morena belong to the Old World Realm and is closely related to Emsian fauna of Australia and Canada. The fauna indicate an Emsian age for the stromatoporoid-bearing beds in the “Peñón Cortado Limestone”. Furthermore, the stromatoporoids from the locations “Guadámez II” and “La Chamorra” suggest an Upper Emsian age much more strongly than a Lower Emsian age.