Abstract Sierra de la Estrella outcrops belong to the Sierra del Castillo Unit, which is defined in the Guadiato Area, SW Spain, where sedimentation occurred during the Late Viséan. The Guadiato Area is located on the boundary between the Ossa-Morena and Central Iberian structural zones, in the southwestern Iberian Peninsula, where Lower Carboniferous outcrops are common. The stratigraphic succession from Sierra de la Estrella is dated precisely by means of foraminifers (Zone 15). The studied rocks are interpreted as having developed on a storm-dominated ramp. Microbial buildups occur interbedded between tempestites and marls. Two main types of mud mounds have been distinguished: large tabular and smaller dome-shaped mud mounds, which were developed in a middle-ramp setting.

Abstract Lower Carboniferous (Upper Viséan and Pendleian) rocks from the Guadiato Area, in the southwestern part of Spain, comprise mixed carbonate-siliciclastic platform facies, with siliciclastics predominant. The calcareous intervals contain a highly diversified foraminiferal fauna, composed mainly of endothyroids, although some primitive fusulinids are also present. Fourteen families, 9 subfamilies, 67 genera, and 134 species or species groups of foraminifera have been identified. These allow the identification of zones 14 to 18 of Mamet’s classification. Within this zonal framework the appearance, disappearance, and maximum abundance of selected taxa in the Guadiato Area are described and discussed. The first appearance of foraminiferal species and genera in the Guadiato Area is compared to that in other European (Montagne Noire, northern France and Belgium; Britain; and Ireland) and North African (Algéria and Morocco) basins. It shows that some foraminifera occurred earlier in Spain whereas other taxa occurred later than in these regions. These early or late appearances of taxa are grouped in two trends, which are probably related to tectonic movements coeval with sedimentation in the Guadiato Area. Moreover, cluster analysis comparing the foraminifera of the twelve neighboring Carboniferous basins or regions establishes the paleobiogeographical relationship between the Guadiato Area and these other regions.

Abstract Dome-shaped mud mounds ranging in size from 2 m to 25 m thick and from 2 m to 100 m in diameter are present in the Upper Viséan of Sierra de la Estrella, Guadiato Valley, in the Sierra Morena region of SW Iberian Peninsula. The mounds are composed of up to 70% peloidal matrix and contain a varied but sparse assemblage including bryozoans, crinoids, brachiopods, calcareous algae, foraminifers, and gastropods. A three-stage biotic succession is recognizable in the mounds. The first stage consists of crinoid-sponge spicule packstones. The second stage is represented by a low-diversity, autochthonous assemblage of scattered sponges and up to 40-60% by volume of the microproblematical taxon Saccamminopsis fusulinaeformis (McCoy). The third stage consists of peloidal framework and cementstone with abundant primary growth cavities. These rocks are interpreted to be microbial boundstone-cementstone. The three stages of mound growth developed below storm wave base, and the probable coeval, level-bottom beds consisting of marls are interpreted to have been deposited in a dysphotic environment.

Abstract The Carboniferous Foraminifera are composed of representatives of three classes: Fusulinata, Miliolata and Nodosariata. Despite ample literature on Paleozoic Allogromiata and Textulariata, the real presence of these classes remains questionable during the Carboniferous and they are thus excluded herein. The main biostratigraphical markers belong to the superfamilies Archaediscoidea, Lasiodiscoidea and Bradyinoidea, even if many genera among the archaediscoids still have a controversial nomenclature, as well as do some lasiodiscids and bradyinoids. Secondary biostratigraphical markers belong to Lituotubelloidea (= ‘Tournayelloidea’ of the authors), Endothyroidea and Loeblichioidea (these latter giving rise to the primitive Fusulinida). The Miliolata appear at the Visean/Serpukhovian boundary interval. The typical Carboniferous miliolates are primitive nubeculariins and cornuspirinins. Tubiphytids might be miliolate and cyanobacterium consortia, derived from the nubeculariin Palaeonubecularia . The most primitive nodosariates (syzraniids) appeared in the Moscovian; and gave rise, in the latest Carboniferous, to Protonodosaria , Nodosinelloides and possibly Polarisella , Paravervilleina and the oldest Geinitzinoidea. Palaeobiological data are mainly provided by the genera Bradyina , Tetrataxis and Climacammina . Palaeobiogeographical distributions of Pojarkovella , Janischewskina, Eosigmoilina , Brenckleina , Spireitlina , Hemigordius and Syzrania testify to the successive foraminiferal migrations between the Palaeotethys, Ural and Panthalassan oceans. Two taxa are created: Eoparastaffellidae and Banffellinae.