Trabajos de Geologia最新文献

{"title":"Procedimiento estereológico para la cuantificación del tamaño medio de grano de rocas en 2-D: aplicación a la interpretación petrofísica de la velocidad de corte de granitos con útiles diamantados","authors":"A. R. Rey, L. Calleja, L. M. S. D. Río, V. G. R. D. Argandoña, I. Sarriá, N. Delgado","doi":"10.17811/TDG.24.2004.147-153","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.147-153","url":null,"abstract":"Grain size is a fundamental rock-forming characteristic of rocks that can be estimated under very different techniques. In this paper a simple and efficient 2-D stereological procedure for estimating the numerical density and the mean area of crystal sections as well as the area percentage of minerals in thin sections of rocks is presented. An example applied to the estimation of the mean section area and numerical density of the biotite crystals in a thin section of a tonalite is described in detail. Some results of the procedure application in a research project about Pink Porrino granite sawability are also presented.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"164 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134258835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caracterización del comportamiento elástico de materiales pizarrosos del Sinclinal de Truchas mediante ultrasonidos","authors":"M. Sastre, L. Calleja","doi":"10.17811/TDG.24.2004.153-165","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.153-165","url":null,"abstract":"Truchas Syncline slates has been exploited since the second half of the last century to perform roof slate, as the main industrial application which implies an important economic profit to the mine companies working in this area. Petrographic studies from visu to microscopic scale, added to the physical property determinations report a better reological knowledge of this rocks. Ultrasonic measurements led us establish rock elastic constants, by a non destructive method, and it would inform about rock behaviour during exploitation works in slate quarries. Planar fabric and inclination of the cleavage planes are the main parameters involved in the propagation of the ultrasonic waves including lithologic changes. Maximum values obtained from the ultrasonic propagation are reached when foliation appears at 90o (waves travel along foliation planes) and minimum when waves travel at 0o, perpendicular way at foliation plane. Linear correlation has been obtanined to the main elastic constant from slates but not to Poisson relation.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127372093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Litoestratigráfica del sector occidental de la cuenca cretácica de Asturias","authors":"M. G. Claverol, B. G. Fernández, E. Casares, J. C. García-Ramos","doi":"10.17811/TDG.24.2004.43-81","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.43-81","url":null,"abstract":"espanolSe realiza una puesta al dia del conocimiento de los materiales cretacicos en el area central de Asturias. Son definidas en la zona occidental de la cuenca cretacica 10 formaciones, tres de ellas se establecen aqui por vez primera, tratando de simplificar y unificar la confusa nomenclatura existente hasta el momento. Al establecer las unidades litoestratigraficas se tuvo presente la facilidad para reconocer las formaciones con simples observaciones de campo, de manera que sus limites puedan ser cartografiados sin mayor dificultad (se adjuntan mapas geologicos). Las formaciones descritas, con una potencia total comprendida entre 500 y 600 m, son las siguientes, de muro a techo: Penaferruz, Antromero, Pola de Siero, Ullaga, El Caleyu, La Manjoya, Latores, San Lazaro, La Arganosa y Oviedo. Algunas de ellas se han podido subdividir en miembros. Se produce una alternancia entre las formaciones de naturaleza siliciclastica (Penaferruz, Pola de Siero, El Caleyu, Latores y La Arganosa) y aquellas en las que el contenido en carbonatos es dominante (Antromero, Ullaga, La Manjoya, San Lazaro y Oviedo). La descripcion de las diferentes unidades abarca aspectos variados, tales como: nombres previos, litologia, limites estratigraficos, potencia, microfacies, ambiente sedimentario, contenido fosilifero, afloramientos mas importantes y columnas estratigraficas representativas. De manera novedosa, se logro correlacionar la serie cretacica del litoral de Luanco, al norte de Asturias, con la que aflora en la franja tectonizada (zona intermedia limitrofe entre las cuencas jurasica y cretacica) y, asimismo, con la mejor establecida de la propia cuenca cretacica, mas al sur. Estas correlaciones permitieron completar la sucesion cretacica en este ambito. English: In order to improve the knowledge of the Cretaceous deposits in the central area of Asturias, it has been necessary a reinterpretation of all the available information. A total of 10 formations can be defined in the occidental zone of cretaceous basin, three of them mentioned by the first time, trying to simplify and unify the confused nomenclature used up to the date. In the lithostratigraphic definitions effected, there was born in mind the facility of recognizing these formations into fieldwork so that their limits could be mapped without major difficulty (geological maps are attached). Definitive denominations, with a global thickness among 500 and 600 m, are the following ones, in ascending order: Penaferruz, Antromero, Pola de Siero, Ullaga, El Caleyu, La Manjoya, Latores, San Lazaro, La Arganosa and Oviedo. A few of them could be differentiated into members. An alternation takes place between siliciclastic formations (Penaferruz, Pola de Siero, El Caleyu, Latores y La Arganosa) and those which are dominated by carbonate content (Antromero, Ullaga, La Manjoya, San Lazaro y Oviedo). Description ofthese units includes several aspects such as: previous names, lithology, stratigraphic boundaries, thic","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130575393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"La cinemática del plegamiento: algunas claves geométricas para su interpretación","authors":"F. Bastida, J. Aller, N. C. Toimil, N. C. Bobillo-Ares","doi":"10.17811/TDG.24.2004.9-43","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.9-43","url":null,"abstract":"Computer modelling of fold profiles formed by a specific folding mechanism is possible when the equations to find transformation relationships from points of the initial configuration to points of the folded configuration of the layer are known. From these equations, folds formed by the successive or simultaneous superposition of tangential longitudinal strain, flexural flow and several types of homogeneous strain (layer shortening, compaction, and fold flattening parallel or perpendicular to the axial trace) have been modelled. The geometry and strain pattern of the theoretical folds allow predictions about the characteristics of natural folds formed by the above mechanisms. The strain state in the folded layer is a typical feature of every mechanism or mechanism superposition and it can be described by two types of curves, which show the variation of the major axis plunge of the strain ellipse and the variation of the aspect ratio of this ellipse with the layer dip. Tangential longitudinal strain is the only mechanism analysed that produces different curves for the two boundaries of the folded layer. Ramsay’s classification or classifications based on parameters derived from it also give results specific for every folding mechanism or mechanism superposition. Analysis of folding mechanisms that operated in a specific natural fold can be made by trial and error modelling a fold with the same geometrical characteristics as the natural fold. The geometrical features to be analysed in the latter are those involved in the modelling. In natural folds with cleavage, an approach to the curve of the major axis plunge of the strain ellipse against the layer dip can be obtained by measuring the dip variation of the cleavage as a function of the layer dip. The greatest problem in the kinematical analysis of folding is posed by the difficulty of obtaining strain measurements in folded rocks.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126239583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometría y cinemática de pliegues relacionados con cabalgamientos","authors":"J. Poblet","doi":"10.17811/TDG.24.2004.127-147","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.127-147","url":null,"abstract":"This study pretends to be a compendium of the most relevant aspects developed during the last decades on the geometry and kinematics of thrust-related folds. First of all, the main features of these structures, as well as the goals and the methodology employed to study them, are described. A modern classification of thrust-related folds is presented, and the geometry and kinematics of simple fault-bend folds, fault-propagation folds and detachment folds is described using the most common models. Finally, the techniques proposed to distinguish the different types of thrust-related folds are briefly explained.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129882397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caracterización petrológica y geoquímica de los diques basálticos de Cadavedo (Valdés, Asturias)","authors":"L. G. Menéndez, O. Suárez","doi":"10.17811/TDG.24.2004.81-91","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.81-91","url":null,"abstract":"The Cadavedo basaltic dikes (Valdes, Asturias) form part of a system of dikes and sills that intrudes the cambric sedimentary rocks in the Asturoccidental-leonese Zone. The studied dikes are composed of amphibole and plagioclase as the primary minerals and this association was affected by a subsolidus hydrothermal event. The geochemistry indicates a transitionalalkaline nature of these intraplate basaltic dikes. Rare earth geochemical modelling indicates that these dikes come from a peridotitic source free of garnet (or in very low modal proportions), that underwent low degrees of partial melting.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127850561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Piedras de construcción de la fuente prerrománica de Foncalada: tipos y origen","authors":"F. Mateos, Luis Valdeón, A. Rojo","doi":"10.17811/TDG.24.2004.119-127","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.119-127","url":null,"abstract":"Se realiza un estudio de las aguas subterraneas de la cuenca jurasica de Asturias, diferenciando, por primera vez, dos acuiferos de naturaleza carbonatada dentro de la Formacion Gijon (Triasico Superior-Jurasico Inferior) de tipo fisural y karstico, y varios siliciclasticos en las formaciones del Jurasico Superior: La Nora, Vega y Lastres. La calidad del agua ha sido clasificada en funcion de la conductividad electrica y de los parametros geoquimicos (contenido en sulfatos y bicarbonatos) medidos en las fuentes y surgencias naturales.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132674008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cinética de la ascensión del agua por capilaridad en la “Arenisca de La Marina” (Jurásico superior de Asturias)","authors":"V. G. R. D. Argandoña, L. Calleja, L. M. S. D. Río, A. Rodríguez-Rey, C. Celorio","doi":"10.17811/TDG.24.2004.177-185","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.177-185","url":null,"abstract":"The water movement by capillarity inside La Marina Sandstone (yellow variety) of the Jurassic of Asturias, used as dimension stone, is studied. The rock texture has been characterized under different techniques: elastic wave velocity, Hg porosimetry and X-ray computed tomography. Using the obtained results the modelling and interpretation of the water absorption kinetics due to capillarity have been done. The X-ray tomograhy allows to image the absorption process and to calculate the size of the radius of capillary access. All the results and observations confirm the anisotropic behaviour of the capillarity due to the presence of Liesegang rings perpendicular to the bedding surfaces.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123762316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Actividad sísmica en el Noroeste de la Península Ibérica observada por la red sísmica local del Proyecto Gaspi (1999-2002)","authors":"C. López-Fernández, J. A. Pulgar, J. Gallart, J. M. González-Cortina, J. Díaz, Mario Ruiz","doi":"10.17811/TDG.24.2004.91-107","DOIUrl":"https://doi.org/10.17811/TDG.24.2004.91-107","url":null,"abstract":"The northwestern part of the Iberian Peninsula is of low to moderate magnitude within the seismotectonic context of the Euro-Mediterranean region. However, a significant increase of the seismic activity has taken place since 1995. Several crises occurred in Lugo province, with a main earthquake of magnitude 5,3 in 1997. The poor coverage from permanent stations monitoring the area has traditionally made difficult any rigorous analysis of this activity. Hence, we undertook a detailed study of the local seismicity between 1999 and 2002, based on the deployment of a temporary seismic array. More than 500 local events were collected during this period. The seismicity is scattered over the NW Iberian Peninsula including the continental platform. The highest concentration of events is located in the Southern and Eastern part of Galicia, decreasing progressively towards the western part of Asturias. The most active seismic focus is located near the epicentre of the 1997 earthquake (SW of Becerrea, Lugo). The detection of a poorly-known ‘background seismicity’ through all the NW Iberian Peninsula is another important finding of this work. The results allow to differentiate two seismotectonic domains within NW Iberia: the Atlantic and the Cantabrian domains. In the Atlantic one the seismicity seems to be associated mainly to a NNE-SSW fault system. Lower activity has been found in the Cantabrian domain were the active faults are generally NNW-SSE oriented. The most active zone coincides with the limit between these two zones.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125539870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estratigrafía y estructura del Antiforme del Ollo de Sapo en el área de Viana do Bolo-A Gudiña (Provincia de Orense, NO de España): nuevos datos sobre la posición estratigráfica de la Formación porfiroide Ollo de Sapo","authors":"D. Arias, P. Farias, A. Marcos","doi":"10.17811/TDG.23.2002.1-2","DOIUrl":"https://doi.org/10.17811/TDG.23.2002.1-2","url":null,"abstract":"Detailed mapping of the Viana do Bolo-A Gudina area furnished new data on the stratigraphy and structure of the Ollo de Sapo Antiform in the sector located between the Verin and Truchas synclines. The stratigraphic sequence is formed by several mappable lithological units that can be correlated with the Lower Cambrian-Upper Ordovician succession in the West Asturian-leonese Zone. The Ollo de Sapo formation is interbeded within the Upper CambrianLower Ordovician Cabos Series, which is consistent with the ca. 480 Ma isotopic ages recently obtained in other localities. The general structure of this antiform is characterized by the existence of kilometre-scale open folds with related subvertical crenulation cleavage, developed during the last variscan refolding event. These folds deform previous overturned and N-vergent folds, related with the first variscan deformation event. The whole area is affected by different variscan metamorphic and magmatic events. The strongest one is the high-T metamorphism associated with the intrusion of S-type two-mica granites that lead to partial melting in the metasediments and metavolcanics.","PeriodicalId":252745,"journal":{"name":"Trabajos de Geologia","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130096214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}