132 research outputs found

    Alpine kink bands on foliated rocks of the Central System variscan basement

    Get PDF
    La asociación espacial y cinemática entre kink bands en rocas con foliación varisca y cabalgamientos alpinos en el basamento del Sistema Central, permiten deducir que los primeros tienen una edad cenozoica, y no varisca o tardivarisca. Sistemáticamente, la dirección de los ejes de los kinks es subparalela a los cabalgamientos. Se estudian tres afloramientos clave: El Cabalgamiento de Villares de Jadraque, el Cabalgamiento de Valdesotos y el Retrocabalgamiento de El AtazarThe spatial and kinematic association between kink bands in rocks with variscan foliation and alpine thrusts in the Central System basement, allow us to deduce that the former have a Cenozoic age, and not variscan or late-variscan. Systematically, the fold axes trend of the kinks is sub-parallel to the strike of the thrusts. Three key outcrops are studied: the Villares de Jadraque thrust, the Valdesotos thrust and the El Atazar back-thrus

    Alpine kink bands on foliated rocks of the Central System variscan basement

    Get PDF
    La asociación espacial y cinemática entre kink bands en rocas con foliación varisca y cabalgamientos alpinos en el basamento del Sistema Central, permiten deducir que los primeros tienen una edad cenozoica, y no varisca o tardivarisca. Sistemáticamente, la dirección de los ejes de los kinks es subparalela a los cabalgamientos. Se estudian tres afloramientos clave: El Cabalgamiento de Villares de Jadraque, el Cabalgamiento de Valdesotos y el Retrocabalgamiento de El Atazar.The spatial and kinematic association between kink bands in rocks with variscan foliation and alpine thrusts in the Central System basement, allow us to deduce that the former have a Cenozoic age, and not variscan or late-variscan. Systematically, the fold axes trend of the kinks is sub-parallel to the strike of the thrusts. Three key outcrops are studied: the Villares de Jadraque thrust, the Valdesotos thrust and the El Atazar back-thrust.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

    Variscan inheritance induces Alpine upper crustal delamination in East Spanish–Portuguese Central System

    Get PDF
    The Spanish–Portuguese Central System (SPCS) is an Alpine Mountain range with crystalline basement characterised by a two-layer rheological structure. This structure formed after primary (protolith) and secondary (tectonometamorphic) processes during the extensional collapse of the Variscan Orogen. The SPCS structure is usually controlled by foreland-directed thrusts and strike-slip faults. However, the eastern SPCS is dominated by NW-directed, imbricate backthrusts and lacks the main thrust directed to the foreland basin located southeast of the mountain range (Madrid Cenozoic Basin). The SPCS exhibits a crustal root (> 40 km depth) supporting SE-directed crustal-scale thrusting. Alpine backthrusts sole into an SE-dipping décollement within the Variscan basement. Variscan extension-related structures parallel the SE-dipping geometry of Alpine backthrusts, so they provided favourably oriented rheological weaknesses to accommodate Alpine shortening. Backthrusts geometry, their hanging wall position within the fault that raised the SPCS and gravity modelling support an Alpine crustal delamination process. Tectonic wedging and delamination of the more competent basement occurred in the footwall of Variscan extensional faults (Daurius domain), which enforced the shearing off of a rheologically weaker upper layer of the crust, located in the hanging wall of the Variscan extensional faults (Arriaca domain) by inverting Variscan extensional faults. This led to NW-directed incipient continental subduction of the weaker crust. Intraplate subduction and crustal delamination can be independent from lithosphere-scale inheritance and be conditioned by structural inheritance in the overlying crust. Alpine shortening for the Cretaceous cover is around 17.7 km (10.5% shortening), and 11 km (7%) for the upper-lower crust limit

    Climate effects and stature since 1800

    Get PDF
    During the last 30 years, economic and social historians have collected and analysed large amounts of anthropometric data in order to explore key aspects of the human past. Attention has also been devoted to the examination of factors that can exert an influence on stature. This article outlines the different ways in which climate might influence stature, either directly or indirectly. It then uses Geographical Information System (GIS) software to explore the relationship between variations in temperature and precipitation and the average heights of men in France, India, Mexico, Spain and the United States (US) over the last two centuries. It is possible to observe an influence of climate on stature in some countries, especially during the nineteenth century, but the relationship weakens across time and largely disappears in recent decades. The attenuation of this relationship is attributed to a process of “technophysio evolution” as countries modernised and developed economically

    The Boinás Cenozoic thrust (Cantabrian Mountains, Spain)

    Get PDF
    The opencast gold mine of Boinás, has allowed to outcrops the contact between the variscan basement and the Cenozoic sediments. It is observable that the contact is a post - Lower Oligocene thrust, with a N40ºE trend. From a macrostructural point of view, Boinás thrust spreads along more than 10 km with a constant orientation, a vertical gap that reaches 400 m, and a NW vergence. Northwestwards another Alpine thrust develops (Tineo, A l o n s o y Pulgar , 2004) with a parallel orientation an opposite vergence. Between both thrusts a tectonic pop-down appears (Narcea Pop-down). The dynamic analysis shows that this structure was activated by a paleostress tensor with an horizontal s1 trending N139ºE, with a stress regime close to uniaxial compression (R=0.06). This stress allows the geometrical interchanges between s2 and s3. The outcrop also allows to observe a secondary population of normal faults, that fits to an extensional stress tensor (R=0.01) with s3 trending N146ºE, that is coaxial with the main compressive stress tensor. We interpret both fault populations as generated by the tectonic thrust emplacemen

    Specific micronutrient concentrations are associated with inflammatory cytokines in a rural population of Mexican women with a high prevalence of obesity

    Get PDF
    It has been recognised recently that obese individuals have lower concentrations of micronutrients and this may affect the concentrations of inflammatory cytokines. A cross-sectional study was carried out to evaluate the association of specific micronutrients' status with chronic inflammation caused by obesity in 280 women (36·1 (sd 7·5) years) from seven rural communities in Mexico. Measurements of weight, height and waist circumference were made on all women and body composition was determined by dual-energy X-ray absorptiometry. Concentrations of the cytokines IL-1, TNF-α, IL-6, IL-10 and IL-12, lipid profile, and the micronutrients Zn and vitamins A, C and E were determined in fasting blood samples. Ordered logistic regression models were used to determine associations between categorised cytokine levels and micronutrients. It was found that 80 % of women were overweight or obese, and had significantly higher concentrations of C-reactive protein than normal-weight women (P = 0·05). The risk of higher levels of TNF-α, IL-6, IL-10 and IL-12 was reduced significantly among women with higher Zn concentrations (OR 0·63, 95 % CI 0·42, 0·96, P = 0·03; OR 0·57, 95 % CI 0·39, 0·86, P = 0·025; OR 0·63, 95 % CI 0·41, 0·96, P = 0·04; OR 0·62, 95 % CI 0·41, 0·95, P = 0·03, respectively). Higher concentrations of vitamin A were slightly associated with reduced risks of higher levels of IL-1 and IL-12 (OR 0·97, 95 % CI 0·95, 0·99, P = 0·03; OR 0·97, 95 % CI 0·94, 0·99, P = 0·03, respectively); when adjusting for BMI, this association was lost. No associations were found between vitamin C or vitamin E:lipids concentrations and inflammatory cytokines. In conclusion, higher Zn concentrations are associated with reduced risks of higher concentration of inflammation markers in a population of women with a high prevalence of obesity

    Modelación del crecimiento de pollos de engorda criados en pastoreo o confinamiento

    Get PDF
    Objective: To evaluate the growth of pasture or confinement-raised broiler chickens, using the Gompertz, Logistic and Richards models, and identify the most appropriate. Methodology: One hundred ten straight-run broilers Ross 308 were distributed in two systems: pasture or confinement. Birds were weighed every week until 56 d of age. Three growth models (Gompertz, Logistic and Richards) were considered and compared based on three goodness of fit criteria (coefficient of determination, Akaike information criterion and Bayesian information criterion). Results: The initial (L) and exponential (K) growth rates of the Gompertz and Logistic models, respectively, were higher in confined birds (L = 0.1232, K = 0.0779) compared to those raised in pasture (L = 0.0944 , K = 0.0657). The maximum relative growth (K) of the Richards model was lower in chickens in confinement (0.0129) than in pasture system (0.0153). With the three models, higher asymptotic weights (WA) were estimated for confined chickens (3,967.1 to 9,095.5) compared to pasture birds (2,461.7 to 5,192.6). According to the criteria considered, the Richards model had the best fit. Implications of study: The results are only valid for straight-run Ross 308 broiler chickens and under the specified management conditions. Findings: The growth of pasture or confinement-raised broiler chickens can be described with the Gompertz, Logistic and Richards models, however, the latter has a better fit.Objetivo: Evaluar el crecimiento de pollos de engorda criados en pastoreo o confinamiento, mediante los modelos Gompertz, Logístico y Richards, e identificar el más adecuado. Metodología: Ciento diez pollos de engorda mixtos Ross 308 se distribuyeron en dos sistemas de crianza: pastoreo o confinamiento. Semanalmente se obtuvo el peso corporal de cada ave, hasta los 56 d de edad. Tres modelos de crecimiento (Gompertz, Logístico y Richards) fueron considerados y se compararon con base en tres criterios de bondad de ajuste (coeficiente de determinación, criterio de información de Akaike y criterio de información Bayesiano). Resultados: Las tasas de crecimiento inicial (L) y exponencial (K) de los modelos Gompertz y Logístico, respectivamente, fueron mayores en las aves en confinamiento (L = 0.1232, K = 0.0779) respecto a las criadas en pastoreo (L = 0.0944, K = 0.0657). El máximo crecimiento relativo (K) del modelo Richards fue menor en pollos en confinamiento (0.0129) que en pastoreo (0.0153). Con los tres modelos, se estimaron mayores pesos asintóticos (WA) para los pollos en confinamiento (3,967.1 a 9,095.5) respecto a las aves en pastoreo (2,461.7 a 5,192.6). De acuerdo a los criterios considerados, el modelo Richards es el que tiene un mejor ajuste.         Implicaciones del estudio: Los resultados obtenidos sólo son válidos para pollos de engorda mixtos Ross 308 y bajo las condiciones de manejo especificadas. Conclusión: El crecimiento de pollos de engorda criados en confinamiento o pastoreo, puede describirse con los modelos Gompertz, Logístico y Richards, sin embargo, este último tiene un mejor ajuste
    corecore