Geogaceta -- Nº 41, (2006)
Permanent URI for this collectionhttps://hdl.handle.net/10272/8443
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Item type: Item , Vertebrados del yacimiento Holoceno de Kobeaga II (Ispaster, Bizkaia)(2006) Murelaga, Xabier; López Quintana, J. C.; Castaños, Pedro; Guenaga Lizasu, A.; Bailon, Salvador; Zubeldia, H.In this paper the faunistic sample, the stratigraphy and the chronology of the archaeological site of Kobeaga II cave (Ispaster, Bizkaia) is described. The five Classes of vertebrates are represented in this site, where, the mammals are the most abundant with five Orders, nine Families, and fifteen Genera. To end, it is remarked the interest of some species as a paleoecological indicator in the general sketch of the Holocene in the North of the Iberian PeninsulaItem type: Item , Validez e interpretación de los datos geotermométricos de los esquistos cloríticos con circón en las peridotitas de Ronda (Cordilleras Béticas)(2006) Esteban, José Julián; Cuevas, Julia; Tubía, José MaríaThis work reports the most precise geochemical compositions and geothermometric calculations of zirconbearing chlorite schists located at the south-western part of the Sierra Bermeja peridotite massif. The combination of electron microprobe and X-ray diffraction analysis shows the lack of interstratifications within chlorite IIb and allow us the use conventional geothermometers in the calculations of chlorite formation temperatures. Moreover, the application of geothermometers that do not depend on the SiO2 composition of the host rock give us a new value ranges between 289-322 ºC for the chlorite schists formation during the serpentinization of the R onda peridotitesItem type: Item , U-Pb dating of Siluro-Ordovician volcanism in the Verín Synform (Orense; Schistose Domain, Galicia-Trás-os-Montes Zone)(2006) Valverde Vaquero, Pablo; Farias, P.; Marcos, A.; Gallastegui, G.El Grupo Paraño constituye la parte más alta de la estratigrafía del Dominio Esquistoso de Galicia-Trásos- Montes y está expuesto en el núcleo de la Sinforma de Verín. Como al resto del dominio, a este grupo se le ha atribuido una edad Silúrica. Con el fin de comprobar su edad se ha datado por el método U-Pb en circón una traquita félsica, de afinidades alcalinas, que ha proporcionado una edad Siluro- Ordovícica de 439,6+/-5 Ma. Esta edad demuestra que la estratigrafia del Dominio Esquistoso es más compleja de lo que se suponía, e invalida la correlación entre las rocas volcánicas en Galicia Central y las riolitas alcalinas de la Serie de Queiroga en la zona de Cabo Ortegal, datadas con una edad de 475 Ma por el método U-PbItem type: Item , Tectonic and Stratigraphic Description and Mapping of the Santa Susana Shear Zone (SSSZ), the SW Border of Ossa Morena Zone (OMZ), Barrancão – Ribeira de S. Cristóvão Sector (Portugal): Theoretical Implications(2006) Oliveira, H.; Dias da Silva, I.; Almeida, P.Se ha realizado una cartografía de la Cuenca de Santa Susana (Vestfalialiense D – Estefaniense A), situada en el limite SW de la ZOM con la Zona Sur Por tuguesa (ZSP). Esta región se caracterizada por una frontera tectónica de orientación N-S entre la ZOM (este) y la ZSP (oeste). La Zona de Cizalla de Santa Susana (ZCSS) está relacionada con la generación de cuencas en pull-apart, con un estilo tectónico transtensivo dextrógiro, seguido por un régimen progresivo y diacrónico, afectando secuencias sedimentarias contemporáneas. Esta importante zona de cizalla evidencia similitudes geométricas, cinemáticas y temporales, con la estrutura tardi-varisca de Porto-Tomar-Ferreira do AlentejoItem type: Item , Some misleading boudin-like structures(2006) Bons, Paul D.; Druguet, ElenaLas estructuras de boudinage son indicadoras de extensión paralela a las capas. Sin embargo, existen estructuras que poseen un alto grado de similitud con los boudins pero cuyo origen no está relacionado con un estiramiento significativo paralelo a las capas, venas o diques aparentemente boudinados. En el presente trabajo se discuten dos de estas estructuras: shear bands y venas en fracturas en zigzag. Las fallas o shear bands pueden cortar una capa separándola en bloques o «boudins» (de ahí el término clivaje de crenulación extensional). Sin embargo, en determinadas circunstancias, estas estructuras pueden formarse en capas paralelas al plano de no estiramiento en cizalla simple, pudiendo así dar un impresión falsa de extensión de la capa. Un segundo tipo de «falsos boudins» lo constituyen las venas formadas por la abertura de grietas a lo largo de una fractura, dando lugar a una ristra de cuerpos elongados cuya geometría presenta gran semejanza con los boudins reales formados por estiramientoItem type: Item , Riodeva sites (Teruel, Spain) shedding light to European Sauropod phylogeny(2006) Royo Torres, Rafael; Cobos, Alberto; Aberasturi, A.; Espílez, Eduardo; Fierro, Ignacio; González, Ángel; Luque, L.; Mampel, Luis; Alcalá, LuisEn el término municipal de Riodeva se han excavado hasta el momento tres yacimientos de dinosaurios situados en sedimentos de la Formación Villar del Arzobispo, de edad Titónico-Berriasiense. En ellos se han recuperado restos de tres individuos de saurópodos per tenecientes al menos a dos taxones diferentes, determinados como Diplodocinae indet. y como Eusauropoda indet. Los restos hallados en Riodeva corroboran las propuestas apuntadas en trabajos anteriores acerca de la presencia del clado Diplodocinae y de eusaurópodos basales en la Península Ibérica. El registro de estos taxones proporciona nuevos datos para documentar la evolución de los saurópodos durante el Jurásico Superior y el Cretácico Inferior en EuropaItem type: Item , Resultados preliminares en la caracterización geométrica 3D de un litosoma arenoso de progradación deltaica mediante georadar (GPR) (Fm. Arenisca de Roda, Eoceno, Cuenca de Graus-Tremp)(2006) Coll, Miquel; López Blanco, Miguel; Marcuello, AlexA set of GPR profiles have been recorded in order to determine the 3D geometry of a prograding delta-front sandbody (Roda sandstone formation, Eocene, Graus-Tremp basin). Common Mid Points (CMP) also have been recorded to obtain the velocity of the electromagnetic wave in ground. In order to build the top surface of a 3D prism a set of topographic points have been acquired. Most of the GPR profiles are oriented parallel to the progradation direction (NNE-SSW) and show the expected geometries. The 3D prism has been built from the individual profiles, which shows the three dimensional geometry of the sandy lithosomeItem type: Item , Respuesta mecánica de medios bifásicos. Influencia de la disposición espacial de sus constituyentes(2006) Griera, Albert; Takeda, Y. T.; Gómez Rivas, EnriqueNumerical simulations were per formed to investigate the strain-dependent behaviour of rheological response to flow of two-phase rocks. Two types of microstructures were considered: strong phase supported (SPS) and weak phase supported (WPS) structures. Additionally, the influence of the spatial distribution of the inclusions and the volume of weak fraction were studied. The results showed a non linear behaviour of the composite, with strain hardening preceding strain sof tening in both structures. Otherwise, an anisotropic dependence on viscous and elastic properties was observed in relation to the initial orientation of the inclusions. This behaviour is related with shape changes of phases, the development of internal instabilities and the deformation partitioningItem type: Item , Relación entre composición de areniscas y procedencia. Casos de estudio en areniscas paleozoicas de la Zona Surportuguesa(2006) Moreno Garrido, María Carmen; Sierra del Pino, SoniaTwo different types of Upper Paleozoic sandstones from Southportuguese Zone are studied. Data coming from petrographic, sedimentological and regional analyses of the sandstones point to two different anomalies in relation with Dickinson and et al.’s provenance model. Discrimination between modal analysis and petrographic study of arenites is noted, as well as discrimination between source and tectonic setting of the provenance areaItem type: Item , Química de las aguas de goteo en la Cueva de Canelobre (Alicante)(2006) Cuevas González, Jaime; Andreu Rodes, José Miguel; Cañaveras, J.C.; Hernández Bravo, J. A.; Sánchez Moral, S.; García del Cura, María AngelesThe Cave of Canalobre, located in the west middle of the Alicante province, is one of the most visited cave in Comunidad Valenciana. During the last years some drip water samples have been collected. The analytical results have allowed us the physico-chemical characterization of the waters. Use of principal components analysis (PCA) and a study of hydrodynamic equilibria have allowed us to stablish that the proper ties and composition of these waters depend on both dissolution proccess of the rock during the downward passage and climatic concentration in the soil of the components dissolved in the rainwaterItem type: Item , Pulsos de inundación marina en la terminación de una plataforma carbonatada (Aptiense inferior de Aralar, Cuenca Vasco-Cantábrica)(2006) Millán, M. I.; Fernández Mendiola, Pedro Ángel; García Mondéjar, JoaquínThe Lower Aptian Sarastarri Limestone unit (Aralar, nor thern Spain), mainly consists of rudist and coral micrites and is nearly 200m thick. The uppermost 30m of the unit show sharp-based marly intervals attributed to two drowning events. Both marly intervals are immediately preceeded by laminated bioclastic rudstone facies, attributed to quick shoaling processes ending with subaerial exposure. A change of local subsidence conditions from uniform during the Sarastarri Limestone episode, to varying with distance during the Lareo Marl succeeding episode, is invoked to explain both drownings. Influence of oceanographic causes reported in other contemporaneous carbonate platforms is, however, not excludedItem type: Item , Procedencia de los conglomerados sinorogénicos de La Pobla de Segur, Pirineos centro-meridionales(2006) Barsó Romeu, D.; Ramos Guerrero, EmilioClast composition of conglomerates in sedimentary record has been broadly used in palaeogeographic and palaeotectonic reconstruction, as they reflect the litology of the source area. Moreover, in sintectonic sediments, as in the case here analized, clast composition informs about the kinetic and deformational history of the orogen. This paper focuses about clast conglomerate analyses in sinorogenic sediments of La Pobla de Segur basin in order to analyse his provenance in relation to thrust-sheet emplacement in the Pyrenees, during Eocene-Oligocene timesItem type: Item , Procedencia de los materiales terrígenos finos del Paleógeno continental, zona de Vic, NE España(2006) Balañá, J.; Colombo Piñol, Ferrán; Vaquer, R.In the Vic area, the non-marine Palaeogene clastic materials are arranged in two successive lithostratigraphic formations: the lower, Vilanova de Sau (VS) mainly composed of lutites and some channels of sandstones, and the upper, Romagats (RO) mainly consisting of conglomeratic sandstones with few lutitic intercalations. The VS is interpreted as distal and lateral alluvial fan facies, whereas the RO is regarded as alluvial fan proximal facies. The clay mineral analysis, the study of the main palaeocurrents and the different clast lithologies distribution along the studied stratigraphic logs suggest that the source area was located to the east of the present outcrops. In addition, the geochemical analysis of the fine-grained materials provide more evidence that the main source area was placed eastwards, at the area at present occupied by the Mediterranean sea and relatively near the coastItem type: Item , Primeros datos bioestratigráficos de los grupos evaporíticos de la Cuenca de Fortuna (Cordillera Bética)(2006) Tent Manclús, José Enrique; Lancis, Carlos; Dinarès Turell, Jaume; Estévez, AntonioThe present work offers the first biostratigraphic calibration based on calcareous nannoplankton of the three evaporitic assemblages in the Rio Chicamo section. The A. primus FAD is registered at the upper part of the Sanel marls, above the lower gypsum, and bellow the Tale gypsum. The A. delicatus FAD, and the A. amplificus FAD occurs in the lower and upper part of the Chicamo Cycles, respectively, which allow to calibrate the Chicamo Cycles reversal as the chron C3Ar. The Tortonian/Messinian boundary is found at the Tale gypsumItem type: Item , Primeras evidencias de paleoterremotos en la falla de Carboneras: estudio paleosismológico en el segmento de La Serrata(2006) Moreno, Ximena; Masana, E.; Gràcia, E.; Pallàs, R.; Ruano, Patricia; Coll, Miquel; Stepancíková, P.; Santanach, P.A paleoseismological analysis was performed along the La Serrata segment of the Carboneras fault (Eastern Betics) in order to establish its seismic potential. The site was selected after a general geomorphological analysis of the whole fault and af ter a near-fault study of the surface geology. Trenches across the fault exposed colluvial wedges, which evidenced sudden deformation events (paleoear thquakes). The Carboneras is, thus, a seismogenic fault. Evidence of a minimum of four events in the last 50 ka was detected suggesting a mean recurrence period of 14 ka. The geometry of the units and S-C structures observed in trenches indicate a lef t-lateral with some reverse component movement along the fault in its most recent activityItem type: Item , Presencia de Scapanorhynchus raphyodon (Agassiz), en el Turoniense Inferior de Picofrentes (Cordillera Ibérica septentrional, Soria, España)(2006) Pascual, Carlos; Hernández, N.; Latorre, P.; Sanz Pérez, EugenioPicofrentes is one of the most important reference sections for the Cenomanian -Turonian, in the Northern Iberian R ange, characterized by the presence of an abundant marine fossil content, notably ammonites. A single, isolated specimen of shark tooth shark belonging to the species Scapanorhinchus raphyodon (Agassiz) has been found for the first time in this area. This species, common in other places during this stratigraphic interval, lived in marine waters of open continental platforms as do its recent descendants (Mitsukurina owstoni, Jordan)Item type: Item , Presencia de la icnoespecie Dactyloidites ottoi en el complejo de abanico costero de Sant Llorenç del Munt (Eoceno, Cuenca del Ebro, NE de España)(2006) Gibert, J. M. de; López Blanco, Miguel; Ramos Guerrero, EmilioThe presence of Dactyloidites ottoi is first recorded in the Eocene Sant Llorenç del Munt fan-delta complex. This constitutes the first citation for the Paleogene. The ichnospecies occurs in the lower part of a prograding fan-delta front sequence, associated to other traces produced by sediment-feeders. This association is substituted in the upper part of the sequence by abundant vertical Ophiomorpha indicating an increase of energetic conditions. The paleoenvironmental setting interpreted for Dactyloidites is consistent with that of previous described occurrencesItem type: Item , Preliminary paleomagnetic and paleocurrent data from the mid-Cretaceous Black Flysch Group, Western Pyrenees: tectonic implications(2006) Agirrezabala, Luis Miguel; Dinarès Turell, JaumeDatos paleomagnéticos y de paleocorrientes preliminares correspondientes a depósitos turbidíticos en torno al monoclinal sinclinal de Aitzeta (margen norte de la Cuenca Vasco-Cantábrica) indican rotaciones de eje vertical de bloques de edad Albiense superior (Subzona C. auritus) y terciaria (?). Los datos, combinados con los rasgos estructurales del área, evidencian una rotación antihoraria de ~27º (bloque de Deba) durante la Subzona C. auritus, y rotaciones antihorarias de ~27º y ~55º (bloques de Galdonamendi y Mizkia, respectivamente) y horarias de ~40º (bloque de Andutz) de edad terciaria (?). Los resultados obtenidos son coherentes y permiten reconstruir la compleja historia estructural y deposicional del áreaItem type: Item , Petrografía, geoquímica y posible origen del plutón de Salvatierra de los Barros (Zona de Ossa Morena, Badajoz)(2006) Carracedo Sánchez, Manuel; Sarrionandia Eguidazu, Fernando; Eguiluz, Luis; Apalategui, OctavioThe Salvatierra de los Barros pluton is mainly composed by medium grain biotite monzogranites and granodiorites, with common monazite and apatite, and lesser cordierite and allanite. These rocks show massive structure and apparent isotropic fabric, but have a solid state, brittle to brittle – ductile microstructural deformation. These rocks are peraluminous, with variable amounts in potassium, high contents in calcium and low contents in ferromagnesian minerals; they have also normative corundum. Radiometric data obtained by different authors are in agreement with our geochemical data, and indicate an hibrid origin from mixing of pelitic melts and basaltic melts, in a Cadomian post-collisional settlingItem type: Item , Nuevos yacimientos de icnitas de dinosaurios carixienses. Sur del Alto Atlas Central (Goulmima. Marruecos)(2006) Hadri, Majid; Boutakiout, Mohamed; Pérez Lorente, FélixOn the nor th of the Goulmima-Tinerhir line three new dinosaur ichnological sites were discovered. The new ichnites and sites (21 and 3) are added to the 23 footprints and 4 outcrops known until now. All sites are in the Aghbalou Formation (Carixian) being those described in this work, older that previously known. Eubrontes, other not identified theropod and possibly sauropod ichnites are described in the new localities. The litology and the direct and indirect structures accompanying of the footsteps also suppose a contribution for the extension of variation both in the sedimentary materials and morphologic ichnological types in the region