223 research outputs found
La zona wolframífera centro-oriental de Salamanca
[Resumen] Las mineralizaciones e indicios más importantes se encuentran a pocos kilómetros al sur de la capital de provincia, dentro de un área metamórfica de grado medio, con granitos de carácter esencialmente leucocráticos; las concentraciones de más interés aparecen en masas estratiformes, en series detríticas con dominio de porfiroides, areniscas, térrlinos pelíticos y grauváquicos etc., básicamente en dos niveles: en bandas alternantes con neises biotítico-feldespáticos ricos en rutilo yapatito, en el seno de esquistos turmaliníferos, yen bandas calcosilicatadas, con fuerte dispersión en pequeños granos y venas. El metamorfismo regional, posterior, complica notablemente el problema genético, pero se han puesto de relieve algunos factores muy significativos: a) Abundancia de series con niveles ricos en boro. b) Existencia de rocas con aporte volcánico. c) Presencia de niveles wolframíferos asociados a bandas feldespático-biotíticas ricas en apatito. d) Scheelita en bandas calcosilicatadas con minerales que contienen elementos halógenos[Abstract] The main mineralizations are found near of Salamanca city, several kilometers toward the South, ¡nto a metamorphic area of medium to high grade, with leucocratic granites; strongest concentrations are in stratabound rocks, etc., mainly in two levels: alternate bands with rich apatite and rutile gneiss, ¡nto tourmaline schists, and calco-silicate beds, with big dispersion in little grains and veins. The later regional metamorphism is a powerfu! complication feature, but some interesting
characteristic have been emphasised: a) Series abundance rich in bore. b) Existence of rocks with volcanic participation. c) Presence of tungsten-bearing levels associated to feldespathic-biotitic bands with much apatite. d) Scheelite in calcosilicate levels, together with hllogen-rich mineral
Factores geológicos y genéticos en los yacimientos wolframíferos del norte de la provincia de Salamanca
[Resumen] Las mineralizaciones más importantes de este área aparecen como intragraníticas, con scheelita como mineral esencial, presente dentro de bandas paralelas. El proceso metalogenético se inicia con bastante precocidad, según mecanismos que implican fuertes actividades de disoluciones iónicas de elementos alcalinos, manifestado por el desarrollo de feldespatos potásico y sódico. Con posterioridad, la moscovitización llega a ser importante, incrementándose la acidez del medio; las sucesivas paragénesis mineralógicas reflejan los cambios de basicidad y potencial redox del ambiente. Tales acontecimientos se regulan por los factores geológicos condicionantes de la consolidación granítica, que se desarrollan de manera desigual dentro de la zona estudiada.[Abstract] The main minerals of the ore deposits are scheelite and quartz, in paralIel intragranitic bands. The mineralising process begins early, by mechanisms impliying strong activity of alcaline-ion solutions; this is evidenced by potassic and sodic feldspars development. Later, the muscovitisation
will be important, with increasing the acidity; the next mineralogical paragenesis reflect alcalinity and Et, changes, events reguled by geological features than are responsible of the granite consolidation,
although these phenomena are developed unequally in the studied zone
Ground temperatures, landforms and processes in an Atlantic mountain. Cantabrian Mountains (Northern Spain)
This research was supported by the Formación de Profesorado Universitario FPU13/05837 (Ministerio de Educación Cultura y Deporte) program, by the OAPN 053/2010 (Organismo Autónomo Parques Nacionales, MAGRAMA) project, by the I + D + I CGL2015-68144-R (Ministerio de Economia y Competitividad) project, by the Leverhulme Trust International Network Grant IN-2012-140 and the Royal Geographical Society Dudley Stamp Memorial Award.Peer reviewedPostprin
Quaternary glacial evolution in the Central Cantabrian Mountains (Northern Spain)
Peer reviewedPostprin
Geoquímica del W en el área circundante al yacimiento de cheelita de Barruecopardo (Salamanca)
La microclinización, proceso ácido débil, implica una corrosión de plagioclasas y una transformación biotita-clorita, con paso del W de dicha biotita a la fase volátil, bajo forma compleja. El descenso de presión en las fisuras (filones) hace precipitar a los wolframatos. Este mecanismo explica el empobrecimiento en W en las inmediaciones del yacimiento, y justifica una explicación geoquímica y mineralógica expuesta precedentemente
Geoquímica del W en el área circundante al yacimiento de cheelita de Barruecopardo (Salamanca)
La microclinización, proceso ácido débil, implica una corrosión de plagioclasas y una transformación biotita-clorita, con paso del W de dicha biotita a la fase volátil, bajo forma compleja. El descenso de presión en las fisuras (filones) hace precipitar a los wolframatos. Este mecanismo explica el empobrecimiento en W en las inmediaciones del yacimiento, y justifica una explicación geoquímica y mineralógica expuesta precedentemente
Histogram Reweighting Method for Dynamic Properties
The histogram reweighting technique, widely used to analyze Monte Carlo data,
is shown to be applicable to dynamic properties obtained from Molecular
Dynamics simulations. The theory presented here is based on the fact that the
correlation functions in systems in thermodynamic equilibrium are averages over
initial conditions of functions of the trajectory of the system in phase-space,
the latter depending on the volume, the total number of particles and the
classical Hamiltonian. Thus, the well-known histogram reweighting method can
almost straightforwardly be applied to reconstruct the probability distribution
of initial states at different thermodynamic conditions, without extra
computational effort. Correlation functions and transport coefficients are
obtained with this method from few simulation data sets.Comment: 4 pages, 3 figure
Multi-scale Web Mapping for Geoheritage Visualisation and Promotion
Due to the renewed interest for sites of geological interest, both in nature conservation and tourist sectors, numerous regional and national geosite inventories have been carried out in several countries during the last two decades. For this purpose, various assessment methods have been developed and published. The issue of the representation of the results of inventories—in particular, the mapping system, the question of updating data—remains open. Moreover, if in the field of nature conservation, practitioners are used to working with GIS, it is not the case in the tourist sector where data must be delivered to the users in open-access and easy-to-use formats. This paper discusses what opportunities of web mapping methods and techniques there are in the domain of geoheritage assessment and promotion. A web mapping application in Google Maps application programming interface (API) framework is proposed to disseminate the results of geosite inventories carried out in Switzerland both at national and regional scales. The interest of the proposed application is discussed according to three main criteria: mapping interests and limitations, management purposes and interpretive issues
Late Pleistocene climate of the northern Iberian Peninsula: New insights from palaeoglaciers at Fuentes Carrionas (Cantabrian Mountains)
Producción CientíficaNew Be dates for glacial landforms in the Fuentes Carrionas area (Cantabrian Mountains, nothern
Spain) are presented. Mapped and dated landforms in Fuentes Carrionas made possible a palaeoglacier
reconstruction for four glacial stages. Results were compared to other nearby palaeoenvironmental proxies, so a
final approximation on the mean annual temperature and annual precipitation that caused the four glacial advance
stages is proposed. Glaciers reached their maximum extension at 36 ka, in a cold and dry environment. A second
advance stage took place between 18.5 and 19.5 ka, during the Last Glacial Maximum (LGM), when glaciers
advanced in a wet environment, with positive rainfall anomalies. A third glacial advance was dated during the Oldest
Dryas, in which climate shifted to extremely cold and dry conditions. Finally, a last stage has been identified and
proposed to the Younger Dryas, in which precipitation anomalies are negligible. Our results confirm some of the
previously made palaeoglacial and palaeoenvironmental inferences for the Iberian Peninsula, as well as provide
Q4 valuable and accurate anomalies, which are useful for climate modelling.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R
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