39 research outputs found
Calcimicrobial-archaeocyath-bearing clasts from marine slope deposits of the Cambrian Mount Wegener Formation, Coats Land, Shackleton Range, Antarctica
The carbonate clasts from the Mount Wegener Formation provide sedimentological, diagenetic and palaeontological evidences of the destruction and resedimentation of a hidden/unknown Cambrian carbonate shallow-water record at the Coats Land region of Antarctica. This incomplete mosaic could play a key role in comparisons and biostratigraphic correlations between the Cambrian record of the Transantarctic Mountains, Ellsworth-Whitmore block and Antarctic Peninsula at the Antarctica continent. Moreover, it represents a key record in future palaeobiogeographic reconstructions of South Gondwana based on archaeocyathan assemblages
Lower Cambrian archaeocyaths from Navalcastaño (Sierra Morena, Córdoba, Spain): Systematics and biostratigraphy
El hallazgo de arqueociatos en la localidad de Navalcastaño se realizó en 1971, posteriormente en 1973 se recogió abundante material con arqueociatos del que se hizo un somero estudio y cuyos datos fueron incluidos en la Tesis Doctoral de uno de los autores (A.P.). En este trabajo se describe el conjunto del material recogido en 1973, 2006 y 2007, se analizan las microfacies carbonáticas en las que se encuentran, se propone la distribución estratigráfica de los taxones descritos y sus correlaciones con otras localidades españolas, del SO de Gondwana y de la placa Siberiana. Se describen y figuran 22 taxones de arqueociatos, entre ellos una especie nueva, Nochoroicyathus castanensis sp. nov. La asociación de taxones de género descrita en Navalcastaño está constituida por Anthomorpha, Cordobicyathus, Coscinocyathus, Dokidocyathus, Erismacoscinus, Fallocyathus?, Morenicyathus, Neoloculicyathus, Nochoroicyathus, Okulitchicyathus, Protopharetra, Rotundocyathus, Taylorcyathus y Urcyathus. La presencia de Anthomorpha en estos materiales nos permite asignarlos al Ovetense Superior, ya que este género es característico de las Zonas VI y VII de este piso en España, que en la escala de pisos rusos equivalen al Botomiense 1 y 2 (PEREJÓN, MORENO-EIRIS & MENÉNDEZ, 2006). De acuerdo con el conjunto de géneros identificados, asignamos la asociación de arqueociatos de Navalcastaño a la Zona VI de Arqueociatos de España, nivel más bajo de aparición de Anthomorpha en la Península Ibérica y en el SO de Gondwana.The finding of archaeocyaths in the Navalcastaño locality occurred in 1971, followed by collection of abundant material with archaeocyaths in 1973, which was preliminarily studied and included in the Doctoral Thesis of one the authors (A. P.). All the material collected in 1973, 2006 and 2007 is described in the present paper, together with analyses of the carbonate microfacies in which they were found, the proposal of a stratigraphic distribution of the described taxa and their correlation with other Spanish, SW Gondwanan and Siberian Plate localities.
Twenty-two archaeocyathan taxa are described and figured, among them a new species, Nochoroicyathus castanensis sp.
nov. The association of taxa found in Navalcastaño is made up of the genera Anthomorpha, Cordobicyathus, Coscinocyathus, Dokidocyathus, Erismacoscinus, Fallocyathus?, Morenicyathus, Neoloculicyathus, Nochoroicyathus, Okulitchicyathus, Protopharetra, Rotundocyathus, Taylorcyathus and Urcyathus. The presence of the genus Anthomorpha in these materials allows us to assign the assemblage to the Late Ovetian, which is characteristic of Zones VI and VII in Spain, and equivalent to Botoman 1 and 2 in Siberia, according to the Russian zonation (PEREJÓN, MORENO-EIRIS & MENÉNDEZ, 2006).
In accordance with the whole set of identified genera, we assign the archaeocyathan assemblage from Navalcastaño to
the Spanish Archaeocyathan Zone VI, the lowest level for the appearance of Anthomorpha in the Iberian Peninsula and SW
Gondwana.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEEspaña. Ministerio de Educación y Cienciapu
New documentary data from the Geominero Museum (the Spanish Geological Survey, Madrid) on the archaeocyathan collection from the Ermitas Hill of Cordoba
La colección de arqueociatos del Cerro de las Ermitas (Córdoba) del Museo Geominero ha sido objeto de revisión
recientemente debido al hallazgo de nuevos documentos en relación con el estudio, por parte de uno de los autores, de la vida profesional de D. Eduardo Hernández-Pacheco en el archivo del Museo Nacional de Ciencias Naturales. En esta documentación se pone de manifiesto que los ejemplares de arqueociatos de las Ermitas conservados en el Museo Geominero fueron enviados por Eduardo Hernández-Pacheco antes de 1902 a Lucas Mallada e incorporados a las colecciones del museo y que fueron posteriormente estudiados
por Hernández Sampelayo en 1933 y 1935. Esto implica que ésta es la colección de arqueociatos españoles más antigua depositada en un museo español, despejándose además las dudas del origen y fecha en la cual se llevó a cabo el ingreso del material en los fondos del Museo GeomineroThe archaeocyathan collection of the Ermitas Hill (Cordoba) of the Geominero Museum in Madrid has recently been revised due to the discovery of some documents related to the study by one of this paper’s authors of the professional life of Eduardo Hernández-Pacheco in the National Natural History Museum archives. This documentation shows that the Ermitas Hill archaeocyathan collection now preserved in the Geominero Museum were sent by Eduardo Hernández-Pacheco to Lucas Mallada before 1902 to be incorporated in the museum’s collections and were then studied by Hernández Sampelayo in 1933 and 1935. This fact implies that this collection is the oldest Spanish archaeocyathan collection deposited in a Spanish museum, besides clearing up the doubts about its origins and when the material was in deposited in the
Geominero MuseumDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
Lower Cambrian archaeocyaths from Córdoba Range (Sierra Morena, Spain): a new record
Se estudia la asociación de arqueociatos hallada en niveles carbonáticos de la Formación Pedroche que afloran, de forma dispersa, a lo largo de la Carretera Córdoba-Villaviciosa, al Norte de la ciudad de Córdoba. Los fósiles seencuentran a techo de la sucesión, en niveles tabulares o biostromos con mesoestructura trombolítica. Se describe una nueva especie, Erismacoscinus lucanoi nov. sp. y la asociación estudiada está constituida por tres géneros, Protopharetra, Erismacoscinus y Nochoroicyathus. La edad asignada a estos materiales se corresponde con las Zonas I-III de arqueociatos (Perejón & Moreno-Eiris, 2006) Ovetiense inferior (Cámbrico Serie 2, Piso 3).The archaeocyathan assemblage from carbonate beds of the Pedroche Formation that crop out dispersed along the Cordoba-Villaviciosa Road, North of Cordoba city, is studied. The fossils are in thrombolite biostromes at the top of the succession. A new species is described, Erismacoscinus lucanoi nov. sp. The archaeocyathan assemblage stu- died is consisted of three genera, Protopharetra, Erismacoscinus and Nochoroicyathus. The age assigned to carbonate materials is I-III archaeocyathan Zones (Perejón & Moreno-Eiris, 2006) Early Ovetian (Cambrian Series 2, Stage 3)Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)pu
The westernmost sector of the lower-Cambrian Los Navalucillos Formation: microbialites in tidal deposits, Central Iberian Zone, Toledo Mountains, Spain
In the Central Iberian Zone of the Iberian Massif, the Los Navalucillos Formation, interpreted as tidal and shallow-marine carbonate deposits, contains a significant archaeocyathan faunal assemblage. Two new characteristic exposures are described here from the westernmost outcrops of the formation, close to La Nava de Ricomalillo area: (i) La Estrella, where the rocks are strongly affected by contact metamorphism due to the nearby plutonic complex; and (ii) the Finca Higueruela succession, without calcimicrobial-archaeocyathan boundstones, although different microbialites as stromatolites and oncolites are conspicuous
Fósiles
24 páginas, 43 fotos.-- En: Muñoz Barco, P. & Martínez Flores, E. (coord.).Peer reviewe
Discontinuidades sedimentarias en la transición Cámbrico Inferior-Medio del manto del Esla, Zona Cantábrica
In the Esla nappe, three major discontinuities have been recognized within the Lancara Formation. Discontinuity D1 is located at the top of the white bedded limestones. It is recognized as an erosive contact and marks a sharp change from a peritidal-dominant, homoclinal ramp to a ramp with oolitic and bioclastic shoals distinguished here as the grey lenticular limestones. Discontinuity D2 is placed at the top of the grey lenticular limestones and is the boundary between the lower and upper Lancara members. A discontinuous ferruginous level or hard ground marks the boundary in the Esla nappe. Discontinuity D3 is placed at the bottom of the griotte tectofacies. It marks a major tectonic pulse and the input of fine-grained siliciclastics. In some areas, it is not sharp but gradual. D3 is a diachronous boundary, dated in some areas of the Cantabrian platform. The D3 surface is easily recognisable in SW Europe as a tectonically induced contact reflecting the diachronous and progressive breakdown of some platforms in SW Europe
New Bilbilian (early Cambrian) archaeocyath-rich thrombolitic microbialite from the Láncara Formation\ud (Cantabrian Mts., northern Spain)
Recent palaeontological and microfacies studies carried out on the Láncara Formation (early Cambrian) provide evidence for an interesting, previously undescribed association of archaeocyaths (Salce locality) and microbialites (Salce and Barrios de Luna localities). The archaeocyathan assemblage consists of Archaeocyathus laqueus (Vologdin, 1932) and Pycnoidocyathus erbiensis (Zhuravleva, 1955), indicating an early Bilbilian age (Stage 4, Series 2, Cambrian) for these materials. The analysis of the upper part of the lower member has allowed differentiation of eleven carbonate facies that have been grouped into: i) non-skeletal grain packstone-grainstone, ii) fenestral mudstone-packstone, iii) heterolithic stylonodular facies, iv) microbialites, v) bioclast-intraclast packstone-grainstone. Archaeocyaths occur reworked in stylonodular facies as well as forming small archaeocyaths-thrombolitic patches (centimetre-scale). The archaeocyath-rich thrombolitic microbialites from Salce were developed in very shallow subtidal conditions surrounded by other microbialites and small lenticular intertidal bars in the inner ramp. Toyonian biostratigraphic and paleobiogeographic analyses have also been carried out. After the comparison with Toyonian archaeocyathan rich facies from Gondwana, it has become evident that the early Cambrian record from the Cantabrian Mountains provides the richest generic assemblage from Gondwana for Toyonian time
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