Palaeoecology and palaeobiogeographic relationships of Lower Devonian bryozoans from the Guadámez and Peñón Cortado Sections of Sierra Morena (SW Spain)

Abstract

Lower to Middle Devonian rocks crop out at the Ossa-Morena Zone (SW Spain), between the Guadiana and Guadalquivir Valleys along 200 km (Fig. 1). The Devonian succession comprises more than 600 m of shales, sandstones, limestones and marls. The limestones show reefal features, but they have limited lateral and vertical development. The most complete successions of these reefal facies are located in five sections, Guadámez-2, Arroyo del Lobo, Zújar, Peñón Cortado and Arroyo del Pozo del Rincón (Rodríguez-García, 1978). Pragian reefal facies occur in most of these localities, being best exposed in the Peñón Cortado section. Emsian reefs are only developed in the Guadámez-2 section. During the field trip in 2007 rich bryozoan assemblages occurring in the reefal and peri-reefal facies were collected. The present paper aims the taxonomic description of the abundant and diverse Lower Devonian bryozoan fauna from the Peñón Cortado and Guadámez-2 sections at the Ossa-Morena Zone. Febrel (1963) first mapped the Devonian outcrops near the Valsequillo village, southern from the Sierra del Pedroso. Herranz (1970) and Llopis-Lladó et al. (1970) described the regional stratigraphy of the Sierra del Pedroso and surrounding region, including Precambrian and Palaeozoic rocks. They provided the first description of the Devonian regional stratigraphy. Both papers indicated the presence of reefal facies BACKGROUND