Francisco Javier López-Moro

En el sinclinal de La Codosera se encuentran intercalados con materiales supra-ordovicicos sills de diabasa de dimensiones inusuales en el territorio espanol (longitud kilometrica y potencia hectometrica). Las dimensiones de estos cuerpos y su color negruzco representan factores muy positivos para su explotacion como roca ornamental. Se ha realizado un estudio de la potencialidad de estas rocas en cuatro zonas, seleccionadas por presentar los mejores afloramientos, los cuerpos de mayores espesores, aceptables vias de acceso, localizacion en pendiente y por la ausencia de posibles impactos ambientales. El estudio de la blocometria refleja un tamano de bloque promedio extraible siempre reducido, encontrandose los mayores tamanos en las zonas de Puebla de Obando y Villar del Rey. A partir de sondeos y de cortes realizados en diferentes afloramientos se ha puesto de manifiesto un modelo de zonado diferente para los sills meridionales y septentrionales, con una gran heterogeneidad hacia ...

Basic to intermediate high-K, high-Mg mantle-derived rocks occur throughout the Iberian Massif and are particularly important in the Tormes Dome, where vaugnerites form several stocks and small plutons. One of the largest and geochemically most variable among these plutons is the Calzadilla pluton in the Tormes Dome that crystallized at 318 ± 1.4Ma (Bashkirian; U-Pb TIMS zircon). This age reveals that the vaugnerite pluton was emplaced during the transition from late D2 extensional deformation to early D3 contractional deformation (319 to 317Ma). Large-scale extension in the area resulted, on one hand, in extensive anatexis in the crust due to quasiisothermal decompression and mica-dehydration melting and, on the other hand, in the upwelling of the mantle, which induced partial melting of the enriched domains in the lithospheric mantle. The driving reason why crustal and mantle melts were coeval is extension. The U-Pb ID-TIMS age of allanite is not related to the emplacement nor coo...

This is the dataset of the paper "Sequential crystal overproduction triggering Mg-Cr-Ti-V-P-MREE- enrichment in a single-pulse tholeiitic mafic dike in the Central Iberian Zone, Spain". It provides an explanation to Methods used in this paper and results of numerical modeling. It also includes mineral chemistry of apatite, ilmenite, clinopyroxene, amphibole and plagioclase.

espanolLas rocas basicas e intermedias de afinidad shoshonitica y las muy escasas rocas ultrapotasicas del domo del Tormes presentan clinopiroxenos en mayor o menor medida, correspondiendo los mayores contenidos modales a las rocas menos diferenciadas. Este aserto sugiere que la actividad de la silice tuvo un papel relevante en el proceso de uralitizacion. Composicionalmente, todos los clinopiroxenos estudiados son diopsidos, ricos en Mg y Ca, y pobres en Ti. Las temperaturas obtenidas a partir de esta fase son excesivamente bajas para ambientes magmaticos, sugiriendo la existencia de procesos de reequilibrio subsolidus, sobre todo en las rocas ultrapotasicas. Las condiciones de fugacidad de oxigeno calculadas a partir de la composicion del clinopiroxeno son mas reductoras que las determinadas en la misma roca con la biotita, una fase mas resistente a los reequilibrios subsolidus. En magmas que pueden llegar a tener originalmente hasta un 5,5% en peso de agua es factible postular la...

En el domo varisco del Tormes se han diferenciado tres asociaciones de rocas en funcion de sus diferentes contenidos en feldespato potasico, K,P y LREE: a)asociacion dioritica, con terminos desde dioritas a tonalitas b)asociacion granodioritica, con terminos desde monzodioritas hasta sienogranitos y que incluye a vaugneritas. C)asociacion monzonitica con un rango composicional desde monzodioritas a cuarzomonzonitas porfidico-biotiticas y esporadicamente granitos. Desde el punto de vista del quimismo, la asociacion dioritica es calcoalcalina de alto K, mientras que las otras dos son afines a las shoshonitas. A partir del estudio quimico-mineralogico se establece la naturaleza hidratada(4-5% H2 O) y oxidante(condiciones por encima del tampon Ni-NiO) de estos magmas. Los calculos geotermometricos indican presiones de emplazamiento en torno a 3,5-4 Kbar para las rocas intermedias y entre 4-5 Kbar para los granitos. Las temperaturas liquidus calculadas estan en el rango entre 1060-950oC ...

About 65 % of plutonic rocks from the Variscan Tormes Dome (Central Iberian Zone) consist of equigranular leucogranites, including coarse-grained, medium-grained and fine-grained granite types. A crustal affinity (S-type granite melts) can be inferred, among others, from the following geochemical features: 1) a high A/CNK index; 2) negatively-slopped normalized spidergrams, showing an enrichment of incompatible and mobile elements, such as Rb and K, as well as negative anomalies in Nb, Ti, Sr, Ba and Eu; 3) high REE fractionation values, (La/Lu)n ranging from 28 to 75, and 4) high δ18O (10.3-12.9 ‰). Despite textural differences, mainly in relation to grain size variation, a compositional overlapping is worth noting, making any geochemical approach difficult to discriminate the two-mica granite groups. Variable partial melting degrees after glandular gneisses is unlikely to be the only reason to account for the linear trend on the ACF diagram, since such a trend is characteristic of...

Las rocas plutonicas hercinicas basicas e intermedias del Domo del Tormes forman tres tipos de asociaciones: a) Dioritico-tonalitica b)Monzonitica, con allanita caracteristica, y c)Asociacion granodioritica, con vaugneritas relacionadas. Las texturas de mezclas son comunes en las dos ultimas asociaciones y estan marcadas por la presencia de agregados de feldespato alcalino y/o agregados anfibolicos. Los granitoides I parecen estar relacionados con la asociacion granodioritica, aunque los terminos menos diferenciados y mas ricos en potasio se integran en la asociacion monzonitica. La evolucion geoquimica de las rocas basicas e intermedias es tipica de rocas ricas en potasio: desde las rocas mas precoces dioriticas y tonaliticas, de afinidad calcoalcalina, hasta las mas tardias, las rocas de la asociacion monzoniticas, que son de caracter shoshonitico y puntualmente ultrapotasico. Es relevante la abundancia en Rb, Ba, Cs, Th y LREE. Esta abundancia combinada con las anomalias en Nb, T...

espanolLos anfiboles de las rocas de afinidad shoshonitica del domo del Tormes presentan un rango composicional entre magnesiohornblenda y actinolita. La mayoria parecen ser secundarios y generados a partir de clinopiroxeno, aunque otros, en equilibrio textural con feldespato potasico y localizado en bolsadas, podrian ser primarios. A tenor de su composicion quimica e isotopica se deduce un origen igneo, y no metamorfico, siendo magmaticos los anfiboles de la asociacion monzonitica y postmagmaticos los de las vaugneritas. Los calculos termometricos indican, sobre todo en las vaugneritas, condiciones por debajo del solidus, lo que implica la accion de una fase acuosa exsuelta del magma que ha reequilibrado el sistema. Teniendo en cuenta la composicion altamente magnesica de los anfiboles reequilibrados, se proponen unas condiciones bastante oxidantes de la fase exsuelta, como pone de manifiesto la gran abundancia de titanita. Unas condiciones maximas de emplazamiento de 2,5 kbar calc...

The still active Los Santos granite quarries, about 50 km to the south of Salamanca, have been documented as a source material for many historical buildings in Salamanca. The excellent conditions of the natural outcrops, together with activation of the Via de la Plata Roman route, are essential factors in explaining the competitive use of the Los Santos granite. Two different granite facies, both belonging to the Spanish Central System Batholith, have been distinguished: an external facies made up of biotite (± muscovite) and cordierite-bearing porphyritic monzogranites, and an internal facies, consisting of biotite porphyritic monzogranites, the latter one containing about 15% of biotite in volume. Heterogeneities are shown by both granite in quarries and monuments, microgranular mafic enclaves being the most remarkable feature in the internal facies, whereas internal-flow structures appear to be common at the contact of two facies. Geochemical classification and chondrite-normaliz...

Basic to intermediate high-K, high-Mg mantle-derived rocks occur throughout the Iberian Massif and are particularly important in the Tormes Dome, where vaugnerites form several stocks and small plutons. One of the largest and geochemically most variable among these plutons is the Calzadilla pluton in the Tormes Dome that crystallized at 318 ± 1.4Ma (Bashkirian; U-Pb TIMS zircon). This age reveals that the vaugnerite pluton was emplaced during the transition from late D2 extensional deformation to early D3 contractional deformation (319 to 317Ma). Large-scale extension in the area resulted, on one hand, in extensive anatexis in the crust due to quasiisothermal decompression and mica-dehydration melting and, on the other hand, in the upwelling of the mantle, which induced partial melting of the enriched domains in the lithospheric mantle. The driving reason why crustal and mantle melts were coeval is extension. The U-Pb ID-TIMS age of allanite is not related to the emplacement nor coo...

A Silurian/Ordovician extensional event in the southernmost sectors of the Central Iberian Zone is inferred from the Sm/Nd isochron obtained (436±17 Ma) after the diabase sills from the La Codosera syncline. From the geochemical and mineralogical points of view, the diabase sills are subalkaline and range between high-Mg tholeiite diabases to tholeiite andesites. LREE enrichment, an Nb negative anomaly, the absence

The strategic importance of tantalum and its scarcity in Europe makes its recovery from low grade deposits and tailings interesting. In Penouta, the contents of Ta and Sn in old tailings from an Sn mine are of economic interest. Due to the relatively low grade of Ta of around 100 ppm, a detailed study of the mineralogy and liberation conditions is necessary. In this study, the mineralogy and the liberation characteristics of Sn and Ta ores of the Penouta tailings were investigated and compared with the current leucogranite outcropping ores. The characterization was conducted through X-ray diffraction, scanning electron microscopy, and electron microprobe. In addition, automated mineralogy techniques were used to determine the mineral associations and liberation characteristics of ore minerals. The grade of the leucogranite outcropping was found to be about 80 ppm for Ta and 400 ppm for Sn, and in the tailings used for the liberation study, the concentrations of Ta and Sn were about ...

We study the causes of Mg-Cr-Ti-V-P-MREE enrichment in a 134 m thick mafic sill emplaced in a single magma pulse. Whole-rock chemistry indicates that TiO2 (up to 5.51 wt%) and P2O5 (up to 1.60 wt%) enrichment occurred in a closed system. Immiscibility processes during magmatic crystallization and interaction with late fluids seem to have played little or no role for the Ti-P distribution. Liquid lines of descent for anhydrous and hydrous condi- tions reveal that the melt did not follow a Fenner trend (anhydrous), which may lead to strong Ti or P enrich- ment, but a Bowen trend (hydrous), during crystallization at low fO2 (ΔFMQ-2) and low water contents (0.5% H2O). The Mg-Cr-Ti-V-P-MREE-rich samples are cumulates and their composition is offset from the liquid line of descent due to postcumulus compaction and compositional convection. Theoretical formulation of compaction and compositional convection demonstrates that classical postcumulus scenarios of strong undercooling (sill b150 m thick) and high accumulation rates (ca. 1 m/y), using uniform cooling and anhydrous viscosity values, properly explain the observed Ti enrichment, but not the P and Cr enrichment. Latent heat released during over- production of clinopyroxene, plagioclase, ilmenite, and apatite may result in non-uniform cooling with periods of near-isothermal conditions. Non-uniform cooling may locally reduce the accumulation rate, which temporarily enhances the efficiency of compaction and compositional convection and leads to the development of Mg\Cr\, Ti\V\, or P-MREE-rich cumulates. The efficiency of postcumulus processes declines once the latent heat does not compensate heat loss to the country rock, leading to cumulates with high intergranular liquid fractions and without Cr, Ti, and P enrichment. High water contents in the upper level of the sill facilitate postcumulus pro- cesses and migration of residual liquids and fluids upwards, leading to the formation of abundant pegmatoid pockets and the development of a sandwich horizon that does not follow the liquid line of descent.

Se ha estudiado la procedencia del material pétreo de doce molinos de diferentes yacimientos cogotenses de la Cuenca del Duero. Utilizando una marcha metodológica previa, se alcanza una caracterización petrográfica, mineralógica y geoquímica del material, incluyendo el tratamiento de elementos traza mediante diagramas de normalización y comparación con datos disponibles de áreas fuente potenciales. Esto ha permitido, en muchos casos, la identificación de áreas fuente locales ya que la signatura geoquímica representa una huella arqueológica fidedigna de las facies o subtipos de rocas implicadas. La mayoría de las áreas fuente identificadas son graníticas, existiendo también granodioritas, gneises y areniscas, todas ellas pertenecientes al basamento varisco. Una de estas áreas incluye minerales de cobre, eventualmente aprovechables para metalurgia. Probablemente, ya desde la fase inicial de Cogotas I dejó de regir el principio del mínimo esfuerzo en el aprovisionamiento del material. ...

The subsurface sedimentary succession of the Iberian Trough, Spain was examined using geophysical techniques (analogue seismic profiles) and inverse distance weighted (IDW) interpolation algorithm implemented in a gvGIS open source software. The results showed that the Late Cretaceous succession is divided into two depositional sequences: DS-1 (Late Albian-Middle Turonian) and DS-2 (Late Turonian-Campanian). From the analogical seismic sections, digital data and quantitative isopach maps for DS-1 and DS-2 were obtained. The new isopach maps obtained for the DS-1 sequence showed that the deeper sectors of the basin were located to the northeast and the proximal ones to the southwest. The palaeoshoreline was inferred to be situated in the N 150 direction. Across and parallel to this direction several blocks were delimited by faults, with a direction between 30 N and N 65. The thickness of the sediments in these blocks varied in direction NW-SE, with subsidence and depocentres in hangi...