Magnetoestratigrafía del Eoceno inferior y medio en el frente Surpirenaico (Sierras Exteriores): implicaciones cronoestratigráficas y cinemáticas

Esta tesis describe un trabajo centrado en la aplicaciones de técnicas paleomagnéticas con el fin de abordar diferentes problemáticas y enfoques estructurales en la parte central y oriental de las Sierras Exteriores de la Cuenca surpirenaica (del Pirineo Alto aragonés). Se presenta la adquisición un conjunto robusto y denso de nuevos datos magnetoestratigráficos a lo largo de casi 2 Km de serie en facies marino someras, principalmente de las Formaciones Boltaña y Guara con la finalidad de aportar una nueva cronología en la cuenca para el Cuisiense y Luteciense. Se presentan un conjunto significativo de datos bioestratigráficos para recalibrar de las biozonas de macroforaminíferos bentónicos involucradas. También se presenta un apartado de estudio de desarrollo metodológico de modelos numéricos y un caso de estudio que aborda en problema de solapamiento de componentes paleomagnéticas. Fuente de error que afecta los valores y estabilidad de los datos paleomagnéticos y que gracias a este estudio puede ser cuantificable y abordable. Finalmente, un estudio de generación de datos robustos y de calidad para el control de cinemática de la estructura del anticlinal de Balzes y alrededores del entorno de Arguis permite develar el origen mixto de la curvatura del pliegue y acotar etapas de plegamiento y rotación para las zonas de estudio. Estos aspectos en conjunto aquí desarrollados, aportan gran cantidad de datos de muy buena calidad y representan una aportación innovadora y significativa para el Eoceno inferior y medio de la Cuenca surpirenaica occidental

Cinemática rotacional del cabalgamiento basal surpirenaico en las Sierras Exteriores Aragonesas: Datos magnetotectónicos

The magnetotectonic analysis of 32 sites located along the External Sierras (mainly in Middle Eocene marls) shows the primary character of the magnetisation and pennits the differences between the paleovectors obtained to be interpreted as a result of the rotational kinematics of the southpyrenean floor thrust in the study area. The constancy of the directions of the defined unblocking intervals (300"-425°C for the thermal treatment) and the homogeneity of the magnetic carriers (these were always low coercitivity phases, probably sulphides andlor magnetite) prove the stability of the magnetisation. On the other hand, the primary character of the magnetisation (Middle Eocene) can be demonstrated by: a) the constancy of the magnetic inclination (47.3 +/- 1.7) and its similarity with the reference direction; b) the occurrence of reversals, and the positive result of the fold-test made in the Pico del Águila anticline; c) the consistency between the reference direction (DEC = 005", INC = 51°, a95=6 ") and the direction obtained for the authocthonous footwall (DEC = 005", INC = 38", a95= 8") which crops out in the western sector of the Sierras Exteriores thrust front. The interpretation of the paleomagnetic data within the External Sierras structural framework clearly shows that the kinematics of individual thrust sheets involves a clockwise component, at least during a period of their evolution. The maximum rotation values were found in the western and central sectors (42" and 30" respectively). The age of the rotation decreases towards the west along with the age of deformation of the cover rocks. Starting in late Priabonian the kinematics of the thrust front resulted in a lack of rotation in the central sector of the Sierras, while the western sector undenvent a clockwise rotation. The differential movement between both sectors gave rise to the development or reactivation of structures (i. e. Rasal-Anzáñigo anticlines) that articulated the deformation of adjacent zones with different rotational components

Cinemática rotacional del cabalgamiento basal surpirenaico en las Sierras Exteriores Aragonesas: Datos magnetotectónicos

The magnetotectonic analysis of 32 sites located along the External Sierras (mainly in Middle Eocene marls) shows the primary character of the magnetisation and pennits the differences between the paleovectors obtained to be interpreted as a result of the rotational kinematics of the southpyrenean floor thrust in the study area. The constancy of the directions of the defined unblocking intervals (300"-425°C for the thermal treatment) and the homogeneity of the magnetic carriers (these were always low coercitivity phases, probably sulphides andlor magnetite) prove the stability of the magnetisation. On the other hand, the primary character of the magnetisation (Middle Eocene) can be demonstrated by: a) the constancy of the magnetic inclination (47.3 +/- 1.7) and its similarity with the reference direction; b) the occurrence of reversals, and the positive result of the fold-test made in the Pico del Águila anticline; c) the consistency between the reference direction (DEC = 005", INC = 51°, a95=6 ") and the direction obtained for the authocthonous footwall (DEC = 005", INC = 38", a95= 8") which crops out in the western sector of the Sierras Exteriores thrust front. The interpretation of the paleomagnetic data within the External Sierras structural framework clearly shows that the kinematics of individual thrust sheets involves a clockwise component, at least during a period of their evolution. The maximum rotation values were found in the western and central sectors (42" and 30" respectively). The age of the rotation decreases towards the west along with the age of deformation of the cover rocks. Starting in late Priabonian the kinematics of the thrust front resulted in a lack of rotation in the central sector of the Sierras, while the western sector undenvent a clockwise rotation. The differential movement between both sectors gave rise to the development or reactivation of structures (i. e. Rasal-Anzáñigo anticlines) that articulated the deformation of adjacent zones with different rotational components

Flexural unfolding of complex geometries in fold and thrust belts using paleomagnetic vectors

Three-dimensional reconstructions of the subsurface are an important field in Earth Sciences due to their considerable socio-economic implications as exploration of petroleum resources. 3D reconstruction aims at providing a plausible image of the underground which entail the integration of discrete and heterogeneous datasets. They are based on geometric/mechanic laws and are designed to tackle areas with scarce and heterogeneous data. Restoration algorithms are an important tool to validate these 3D geological reconstructions of the subsurface. Restoration is the way back from the deformed to the undeformed states. Undo the deformation and achieve an initial surface with geological meaning is useful to validate the reconstruction of the folded structure and the deformation processes assumed. The main postulate in most restoration methods is the horizontality of the initial layers while restoration algorithms are based in several deformation processes as flexural slip or simple shear. We deepen in restoration techniques in next chapter but we want to emphasize the importance of a continuous feedback between reconstruction and restoration. This become especially important when complex deformation processes are implied and limited data is available. In addition, restoration tools may also be useful to predict deformation patterns for well characterized structures. However, existing restoration methods do not always succeed for complex structures like non-cylindrical, non-coaxial and/or areas undergoing vertical-axis rotations (out-of-plane motions). We suggest using paleomagnetic information, known in the undeformed (horizontal) and deformed states, as an additional and powerful constraint to improve restoration methods and to reduce the uncertainty of the results. The use of paleomagnetism in restoration tools was recommended in the early 1990¿s. So far, however, relatively few researchers have tried using paleomagnetic information to double-check the rotation inferred from restoration methods and hardly ever paleomagnetism is used as primary information of these tools. In this PhD we want to show how paleomagnetism can reduce the uncertainty in restoration tools when it is used as a constraint, particularly for structures with out-of-plane motions. The bedding plane is the basic 2D reference to relate the undeformed and deformed states, but never could be a real 3D indicator. Our proposal is the usage of paleomagnetism together with the bedding plane as references known in both states. The bedding plane determines the horizontal rotation and paleomagnetism the vertical axis rotation. Paleomagnetic vectors are the record of the ancient magnetic field at the time of the rock formation and we assume that it behaves as a passive marker during the deformation process. Its original orientation can be known in the undeformed surface, and it is represented by the paleomagnetic reference vector. If we see the deformation mechanisms, paleomagnetism allow reducing the number of variables, since it is a passive marker that records the internal deformation and provides us with information of vertical axis rotation. Because accurate paleomagnetic data is necessary to improve results we also work on a good data acquisition. Paleomagnetism may be incorporated in many restoration tools, particularly; we centre our study in geometrical surface unfolding algorithms valid for globally developable surfaces. Developable surfaces are those with Gaussian curvature equal to zero everywhere. These surfaces in geology are stratigraphic horizons folded under flexural conditions that have minimum internal deformation. That implies surfaces isometrically folded with preservation of lengths and angles and consequently with preservation of area. By globally we mean that these constraints are valid almost everywhere but there are areas where internal deformation is possible. We can find this kind of structures in the fold and thrust belts of competent layers at crustal levels. In order to test the restoration methods we develop analog models of complex structures. Laboratory-scale models are based on non-coaxial structures of External Sierras (Pyrenees). These analogs are digitalized with photogrametry and X-Ray CT scanner. In this way, models are completely characterized before and after deformation. This allows the calculus of real deformation of the folded surface and the comparison of the restored surface with the initial one

Analysing non-coaxial folding effects in the Small Circle Intersection method

The Small Circle (SC) tools analyse the stereographic tracks (small circles) followed by the palaeomagnetic vectors during folding processes. Working with interfolding and synfolding remagnetizations, the Small Circle Intersection (SCI) method allows finding the best solution of grouping that should correspond with the remagnetization direction. Once this is known, it is possible to determine the magnetization age as well as the degree of bed tilting at this moment. The SC tools are based on some assumptions, among which the coaxiality between the different deformation events is the one addressed in this work (i.e. absence of vertical axis rotations, VARs, or differential horizontal axis rotations, dHARs). This assumption is based on the necessity of knowing the rotation axis for folding after the acquisition of the remagnetization, and SC tools consider the bedding strike as this axis, something that is only accomplished under coaxial folding. In order to explore how non-coaxiality affects the solutions derived from the SC methods, we first (i) identify the variables that control these errors through simple models that only consider two theoretical palaeomagnetic sites, after that it is possible (ii) to derive the mathematical relationships between them. Finally, we (iii) simulate errors derived from the use of SC tools using a population of 30 palaeomagnetic sites recreating different possible scenarios with VARs and dHARs in nature.Research financed by the projects DR3AM- CGL2014-55118 and CGL2016-77560-C2 from the Spanish Ministry of Science (MINECO) and by the Applied Geology (GeoAP-E0117R) and Geotransfer groups of the Government of Aragon, as well as by the project BU235P18 (Junta de Castilla y Leon, Spain) and the European Regional Development Fund (ERD). It has also benefited from the MAGIBER-II network (CGL2017-90632-REDT) funded by the Ministry of Science, Innovation and Universities

Selecció de novetats editorials de comunicació

Obra col·lectiva biennal, creada per l'Institut de la Comunicació de la Universitat Autònoma de Barcelona (InCom-UAB), l'any 2000. La setena edició, corresponent al bienni 2011-2012, va comptar amb el suport de la Generalitat de Catalunya; el patrocini de Gas Natural Fenosa; la col·laboració científica del Baròmetre de la Comunicació i la Cultura (Fundacc); la subscripció institucional de l'Ajuntament de Barcelona, el Col·legi de Periodistes de Catalunya i la Societat Catalana de Comunicació (filial de l'Institut d'Estudis Catalans); i la col·laboració acadèmica de l'Observatori de la Comunicació Local (OCL InCom-UAB)/URV/Diputació de Barcelona, l'Observatori de Polítiques de Comunicació (OPC InCom-UAB), i el Portal de la Comunicació (InCom-UAB).En el marc del Grup Internacional d'Estudis sobre Comunicació i Cultura (InCom-UAB), reconegut com a Grup Consolidat de Recerca de la Generalitat de Catalunya per al període 2010-2013 (Referència de concessió 2009 SGR 00615).Aquest capítol aporta una selecció d'obres d'autors vinculats a universitats i institucions catalanes, editades a Catalunya durant els anys 2011 i 2012, elaborada a partir de la base de dades del catàleg de la Biblioteca de Comunicació i Hemeroteca General de la Universitat Autònoma de Barcelona, seguint els criteris acadèmics que el Portal de la Comunicació InCom-UAB (www.portalcomunicacio.cat) utilitza a la seva secció "Novetats editorials". Es tracta d'una relació en la qual es prioritzen les publicacions científiques per davant de les publicacions de caràcter més mediàtic i tècnic

Layer parallel shortening and tectonic transport direction inferred by the anisotropy of magnetic susceptibility (AMS) from Central-Pyrenees post-hercynian rocks, Aragón-Subordán valley, Pirineo Oscense

A N-S section has been studied in post-hercynian rocks of a Central Pyrenees sector in order to search for a relationship between magnetic fabric (ASM) and the regional deformation pattern. The section, which is normal to the main ESE-WNW macrostructures, comprises materials from Upper Cretaceous to Eocene (nine sites, 253 samples). Two main types of stretching lineations have been interpreted from the ASM fabrics: The first one is defined by a magnetic lineation parallel to the major structures and interpreted by layer-parallel shortening. The second one is normal to the bedding-cleavage intersection lineation and thus coincides with the regional tectonic transport direction. Both magnetic lineations fit into the bedding surface and them are not related with the regional cleavage, suggesting its early acquisitio

Preliminary paleomagnetic characterization and anisotropy of magnetic susceptibility (AMS) of ancient terraces of the Ebro river

En este trabajo se realiza el estudio paleomagnético preliminar del nivel de terraza más antiguo (198-220 m) del río Ebro, en el sector central de la Cuenca del Ebro. Igualmente se ha realizado un análisis conjunto de la anisotropía de susceptibilidad magnética (AMS) y los datos de paleocorrientes en la zona. Las desmagnetizaciones muestran direcciones con una clara polaridad inversa de alta temperatura (300-675°C), con una componente adicional normal viscosa <100ºC, indicando que la edad del depósito es anterior al límite Brunhes-Matuyama (773.000 años). La ASM muestra un comportamiento más complejo controlado por la mineralogía magnética. Las fábricas con susceptibilidad paramagnética dominante mostraron foliación magnética paralela al plano de estratificación indicando su posible utilidad en el estudio de paleocorrientesIn this work we carry out a preliminary paleomagnetic analysis focused in the oldest fluvial terrace (198-220 m) of the Ebro River, in the central sector of the Ebro Basin. We have also conducted a combined analysis of anisotropy of magnetic susceptibility (ASM) and paleocurrent data in the area. The paleomagnetic record shows a clear high temperature (300-675° C) reverse polarity with an additional viscous normal component <100º C, indicating that the materials were deposited during the Matuyama chron (reverse polarity) which implies an age > 773.000 years. The ASM shows a more complex behaviour controlled by the magnetic mineralogy. Dominant paramagnetic fabrics show magnetic foliation parallel to the bedding indicating their potential utility in the study of paleocurrent

Subcortical brain volume, regional cortical thickness, and cortical surface area across disorders: findings from the ENIGMA ADHD, ASD, and OCD Working Groups

Objective Attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders that frequently co-occur. We aimed to directly compare all three disorders. The ENIGMA consortium is ideally positioned to investigate structural brain alterations across these disorders. Methods Structural T1-weighted whole-brain MRI of controls (n=5,827) and patients with ADHD (n=2,271), ASD (n=1,777), and OCD (n=2,323) from 151 cohorts worldwide were analyzed using standardized processing protocols. We examined subcortical volume, cortical thickness and surface area differences within a mega-analytical framework, pooling measures extracted from each cohort. Analyses were performed separately for children, adolescents, and adults using linear mixed-effects models adjusting for age, sex and site (and ICV for subcortical and surface area measures). Results We found no shared alterations among all three disorders, while shared alterations between any two disorders did not survive multiple comparisons correction. Children with ADHD compared to those with OCD had smaller hippocampal volumes, possibly influenced by IQ. Children and adolescents with ADHD also had smaller ICV than controls and those with OCD or ASD. Adults with ASD showed thicker frontal cortices compared to adult controls and other clinical groups. No OCD-specific alterations across different age-groups and surface area alterations among all disorders in childhood and adulthood were observed. Conclusion Our findings suggest robust but subtle alterations across different age-groups among ADHD, ASD, and OCD. ADHD-specific ICV and hippocampal alterations in children and adolescents, and ASD-specific cortical thickness alterations in the frontal cortex in adults support previous work emphasizing neurodevelopmental alterations in these disorders

El projecte Telephassa: una experiència de cooperació entre biblioteques europees

Exposició dels objectius del Projecte Telephassa del Progrma COMETT-II de les Comunitats Europees, que es centra en la difusió i l'aplicació de com les noves tecnologies poden ajudar a proporcionar serveis d'informació cada vegada més innovadors