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San Sebastián de los Reyes, Spain

Cesari S.N.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Alvarez-Vazquez C.,Centro Paleobotanico | Mendez-Bedia I.,University of Oviedo | Alvarez-Lao D.,University of Oviedo | And 2 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2015

The first record of an anatomically preserved flora from Stephanian outcrops at Arnao beach (Asturias, Spain) is presented. The stratigraphic section is part of a geological heritage site that preserves exceptional Devonian reef deposits. The Carboniferous succession contains coal seams worked by one of the earliest mines in Spain and its plant-fossil assemblages were reported in the 19th century but scarcely revised later. The new assemblages recovered in the beach, during extreme low tides, represent the first record of permineralised trunks in northwestern Spain. Large cordaitalean specimens are referred to a new species of Cordaixylon characterised by non-septate pith, araucarian radial pitting of the tracheids and cross-fields with phyllocladoid pits. Part of the root mantle of Psaronius is preserved in water-worn pebbles, indicating the presence of tree ferns in the palaeoflora. The associated compression/impression assemblage includes lycophytes, sphenophytes, pteridosperms and pteridophytes. A comparison of the assemblage confirms its importance for reconstructing the Late Pennsylvanian floral succession in the region. © 2015 Elsevier B.V. Source

Upper Barruelian, "Saberian," and Stephanian B (Kasimovianlower Gzhelian) strata in northwestern Spain represent a strongly subsiding alluvial plain connected to the Paleotethys and adjacent to a mountainous hinterland. The rocks have been deformed into steeply dipping, often isoclinal synclines delimited by foreland-directed thrust faults; a steep basin margin with paleovalleys occurs on the hinterland side. One of these tectonic outliers is the La Magdalena Coalfield, of "Saberian" age, where the quantification of a substantial floral record (140 taxa) from 85 localities in 1200 m of strata allows us to observe changes in floral composition through time matched with broad changes in sedimentary facies corresponding to increased remoteness from a receding basin margin. Within the context of a humid environment, a predominantly fluvial facies changed upward and in time into more generalized semi-lacustrine and peat-forming facies. Although pteridosperms and marattialean tree ferns (pecopterids) are dominant throughout, a proportional increase in tree ferns is observed for the higher part of the succession where calamitaceans become less common and lycopsids more noticeable. These floral changes reflect wetter sedimentary conditions, conducive to the production of coals (high ash) of limited lateral extent. © 2011 SEPM (Society for Sedimentary Geology). Source

The upper Stephanian fern Sphenopteris hadrophylla Knight, described originally in an unpublished thesis on the Sabero Coalfield in León, NW Spain, is now validly introduced on the basis of new, more complete, material collected from the La Magdalena Coalfield in León. This includes sporangiate pinnae interpreted as possibly attributable to Discopteris Stur. A holotype and paratypes are designated from this material. The more fragmentary specimens from Sabero are recorded also. Additional specimens from Villablino (León), El Bierzo (León), Ciñera-Matallana (León), and the Narragansett Basin in New England (U.S.A.) are referred to and partly illustrated, thus demonstrating the wider distribution of the species. Comparisons are made with several species of Stephanian age known from Europe and North America. Source

Wagner R.H.,Centro Paleobotanico
Review of Palaeobotany and Palynology | Year: 2012

Records of plant megafossils in the Devonian of the Iberian Peninsula refer to sparse drifted remains in marine strata, apart from unidentifiable debris, and misidentified ichnofossils. The age attributions are sometimes questionable. A critical analysis leaves only five localities with incidental Devonian plant megafossils capable of sustaining approximate taxonomic identifications. Another two localities of possible late Devonian age are more likely earliest Carboniferous. The various records are discussed in their geological context, taking into account that the Iberian Massif was constituted from different terranes in Pennsylvanian times. A critical discussion is presented of the reviews published by Montero (2008) and Montero and Diéguez (2010), particularly the latter which adds considerations on floral composition and sedimentary environments which lack a factual basis. A later paper by Cascales-Miñana et al. (2011) is commented on. © 2011 Elsevier B.V. Source

Pendleton J.L.,University of Sheffield | Cleal C.J.,National Museum Wales | Falcon-Lang H.J.,Royal Holloway, University of London | Falcon-Lang H.J.,University of Munster | And 2 more authors.
Review of Palaeobotany and Palynology | Year: 2012

The Bristol Coalfield of southwest Britain, although intensively studied in the early history of palaeobotany, has received little attention for 75. years. Here we review the palaeobotany of the mid-Bolsovian to Cantabrian (Moscovian) Warwickshire Group of the Bristol Coalfield, which comprises, from base to top, the Winterbourne, Pennant Sandstone and Grovesend formations. Based on an investigation of all available adpression and sandstone-cast plant assemblages in a facies context, we develop a new system of biostratigraphical zonation and elucidate palaeoecology. Our key findings are: (1) Using the new biozonation we identify a stratigraphical gap encompassing the early to mid-Asturian, occurring between the mid- and late Bolsovian Pennant Sandstone and the late Asturian Grovesend formations. This tectonic-induced stratigraphical gap most likely relates to the Leonian Phase of the Variscan uplift and can be correlated with contemporaneous hiatuses in the South Wales and other European coalfields. (2) We recognise a diverse patchwork of plant communities as follows: Peat mires of the Bolsovian Winterbourne and Pennant Sandstone formations were dominated by lepidodendrids and ferns, but were replaced by tree-fern and fern-dominated mires in the late Asturian Grovesend Formation. Clastic swamps fringed these mires and were characterised by a diversity of pteridosperm, calamitaleans and ferns. Riparian communities associated with the coarse-grained deposits of large-scale braided fluvial systems that vertically alternate with the coals/shales, variously comprised . Sigillaria, calamitaleans and cordaitaleans, with pockets of pteridosperms and calamitaleans surrounding channel abandonments. In addition, large cordaitaleans were common in drier interfluve and/or hinterland areas. Switching between stable mire communities and disturbed fluvial communities either reflects autocyclic channel switching or allocyclic alternations driven by climate change. © 2012 Elsevier B.V. Source

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