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La presente Tesis doctoral recoge la caracterización petrográfica y geoquímica del manto subcontinental litosférico (MSCL) bajo el centro de la Península Ibérica a partir del estudio de los xenolitos peridotíticos y piroxeníticos del Campo Volcánico de Calatrava (CVC). Su caracterización geoquímica se ha llevado a cabo gracias a la química de roca total y de sus principales minerales constituyentes, tanto de los elementos mayores como los trazas. También se ha podido analizar su composición isotópica (Sr-Nd) para precisar la naturaleza del MSCL muestreado en el centro de Iberia. En la Región Volcánica Central de España, como la denominó Hernández-Pacheco en 1932, caracterizada por su volcanismo básico alcalino y ultraalcalino, y su condición de campo volcánico monogenético, solo se han encontrado xenolitos procedentes del MSCL en seis de sus más de 260 centros volcánicos. Además de los xenolitos ultramáficos en los que se centra esta Tesis, los fundidos alcalinos del CVC también transportaron una rica y variada carga cristalina que consiste en megacristales de clinopiroxeno, anfíbol y flogopita, de acumulados de grano fino clinopiroxeníticos (y glimmeríticos) y una compleja población de macrocristales y fenocristales (clinopiroxeno verde e incoloro, anfíbol, flogopita y olivino)..., This PhD Thesis reports petrographical, mineralogical and geochemical characterization of the subcontinental lithospheric mantle (SCLM) under the central parts of the Iberian Peninsula by the study of ultramafic xenoliths of the Calatrava Volcanic Field (CVF). The geochemical characterization has been carried out by whole rock analyses and the main mafic minerals chemical composition, both major and traces elements. It has also been possible to analyze whole-rock isotopic compositions (Sr-Nd isotopic signatures) to improve the sampled SCLM nature from the center of Iberia.The Región Volcánica de España (named by Hernández-Pacheco, 1932) is characterized by being a monogenetic volcanic field of basic alkaline and ultra-alkaline magmatism. Peridotite xenoliths have been only found in six of the more than 260 volcanic centres of the CVF. The CVF alkaline melts also transported a rich, varied and complex crystal cargo consisting of clinopyroxene, amphibole and phlogopite megacrysts, fine-grained aggregates of clinopyroxenites, with igneous textures and zoned clinopyroxene crystals, and a complex population of phenocrysts (green and colourless clinopyroxene, amphibole, phlogopite, and olivine)...

Much of the lithospheric subcontinental mantle (SCLM) sampled in the Calatrava Volcanic Field (CVF) shows refertilization by alkaline metasomatic agents. The Cerro Pelado and El Palo ultramafic xenolith suites record the best evidence of this type of metasomatism in this volcanic field. Several groups of peridotite (lherzolite, wehrlite, and dunite) and pyroxenite (clinopyroxenite and websterite) xenoliths have been distinguished. Despite having scarce phlogopites and amphiboles as modal metasomatic phases, all studied xenoliths present a variable cryptic metasomatism, highlighted by the strong Fe-Ti enrichment and fractionated REE patterns in the most evolved wehrlite and pyroxenite varieties. They show a common trend of an Fe-Ti-Ca increase, whereas the pyroxenites are more depleted in Fe compared to the lherzolites and wehrlites. Trace-element (REE and multi-trace) patterns are roughly similar among them, suggesting different interactions and refertilization degrees by alkaline silicate melts. The same Sr–Nd isotopic EAR composition, combined with trace-element chemistry of metasomatic xenolith phases and phenocrysts from the Calatrava volcanics, highlights the main role of this magmatism in percolation processes beneath Central Iberia. These mantle xenoliths also show variable amounts of interstitial glass that originated by in situ partial melting, favored by the enriched chemical nature of cryptically metasomatized clinopyroxene during their volcanic transport. This alkaline-refertilized mantle type represents the main domain within the SCLM beneath Central Iberia, as was also recorded in other Western European Cenozoic volcanic fields., Ministerio de Ciencia e Innovación, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

Los xenolitos granulíticos del volcán de La Encomienda (Campo Volcánico de Calatrava) representan un conjunto de composición félsica peralumínica. Su química mineral permite estimar condicio- nes de temperatura y presión en torno a los 883-889 oC y 0.76-0.84 GPa, lo que implica profundidades propias de la corteza inferior (25- 28 km). Se trata de granulitas de tipo charnockítico, metasedimen- tario y metagranítico. Su petrografía y química mineral indican que sus protolitos son de origen ígneo (composición intermedia-ácida) y/o sedimentario. Al comparar con xenolitos granulíticos del Sistema Central Español (SCE), queda de manifiesto que en Calatrava no se llegan a alcanzar las condiciones de ultra-alta temperatura que sí se logran en el SCE, así como el marcado carácter félsico de la corteza inferior bajo la Zona Centro-Ibérica., The granulite xenoliths from the La Encomienda volcano (Calatrava Volcanic Field) represent a felsic peraluminous suite. Mineral chemistry allows estimating temperature and pressure conditions inthe range of 883-889 oC and 0.76-0.84 GPa, in accordance with a lower crustal derivation (25-28 km). These enclaves are charnockitic, metasedimentary and metagranitic granulites. Their petrography and mineral chemistry indicate an igneous (intermediate-acid composition) or sedimentary origin for the protoliths. When comparing with granulite xenoliths from the Spanish Central System (SCS), it is apparent that Calatrava granulites did not attain the ultra-high temperature conditions characteristic of the SCS xenoliths, although both regions point to a mainly felsic nature of the lower crust under the Central Iberian Zone., Ministerio de Ciencia e Innovación, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

So far, the nature and evolution of the lower crust under central Spain have been constrained mainly on the basis of a heterogeneous suite of granulite xenoliths from the Spanish Central System (SCS). In recent years, ultramafic volcanics from the Calatrava Volcanic Field (CVF) have also provided deep-seated crustal xenoliths which have not been studied in detail. Our data, combining mineral, whole-rock and isotopic geochemistry with U–Pb–Hf isotope ratios in zircons from the CVF and SCS xenoliths, highlight the felsic composition of the lower crust under central Iberia. A number of the Calatrava xenoliths represents Variscan igneous protoliths, which are a minor population in the SCS, and were likely formed by crystallisation of intermediate and felsic melts in the lower crust during the Variscan orogeny (leucodiorite protolith age of 314 ± 3 Ma and leucogranite protolith age of 308 ± 2.5 Ma). U–Pb data of metamorphic zircons show that granulite-facies metamorphism mainly occurred from 299 to 285 Ma in both areas. These ages are slightly younger than those of granitic intrusions that could be genetically related to the granulitic residue, which points to a main role of U–Pb isotope resetting in lower crustal zircons during HT or UHT conditions. The zircon U–Pb–Hf isotopic ratios support the idea that the lower crust in central Iberia consists mainly of Ordovician–Neoproterozoic metaigneous and metasedimentary rocks associated with the Cadomian continental arc of northern Gondwana. These rocks provide evidence of mixing between juvenile magmas and an enriched crustal component, ultimately extracted from an Eburnean crust. Other more evolved components present in detrital zircons are likely related to recycling of Archean crust derived from North Africa cratonic terranes., Ministerio de Ciencia e Innovación (MICINN), LA-ICPMS laboratory at the University of Johannesburg, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

Two types of lherzolite xenoliths appear in the Cerro Gordo maar from the Cenozoic Calatrava volcanic field. Hydrous lherzolites (group-1) show a major proportion of metasomatic amphibole (>5 modal%), whereas group-2 lherzolites have only accessory amounts or an absence of amphibole. Group-1 lherzolites show a higher LREE-Ba-Sr-Th content in whole-rock composition compared to group-2 lherzolites. The most depleted group-2 lherzolite xenoliths indicate a low degree of partial melting (<5%) of the mantle source, similarly to other Calatrava xenolith suites. Trace element content combined with Sr-Nd isotopic ratios suggests a protolith mantle source with the characteristics of a depleted MORB Mantle (DMM type). This mantle protolith was later refertilized by subduction-related metasomatism, causing the formation of modal amphibole and obliterating the original MORB-like chemical features in the most transformed xenoliths (group-1 lherzolites). The entrainment of these mantle fragments in the volcanic alkaline magma promoted amphibole breakdown reactions during its transport, generating silica-rich glasses with the associated unusual formation of secondary orthopyroxene. The suprasubduction character of the protolithic mantle combined with previously published Re-Os model ages in nearby lherzolite xenoliths suggests that the sampled lherzolites could represent the old Cadomian mantle wedge of the Central Iberian zone., Secretaría de Estado de Investigación, Desarrollo e Innovación, Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

En el volcán de Los Tormos (Campo de Calatrava) se han distinguido dos grupos principales de xenolitos mantélicos en función del análisis modal, presencia de anfíbol y composición química del clinopiroxeno, lo que permite deducir al menos dos sectores del manto ligados a eventos metasomáticos de diferente naturaleza. El grupo más abundante son lherzolitas con espinela, formados por minerales con contenidos altos de Mg, y clinopiroxeno con bajo contenido en elementos traza incompatibles y espectros normalizados relativamente planos, que evidenciaría afinidad con un manto empobrecido tipo MORB, el manto más primitivo del conjunto. Sin embargo, las anomalías negativas en Nb-Ta y enriquecimiento variable en los elementos más incompatibles (Th, U, Pb, tierras raras ligeras) y elementos móviles (Sr, K, Ba) en dichos espectros indicarían la interacción con fluidos metasomáticos derivados de zonas de ubducción, que actuarían con distinta intensidad. Las wehrlitas con anfíbol destacan por la riqueza en hierro de sus minerales, así como por la composición del clinopiroxeno, con espectros de elementos traza normalizados enriquecidos en los elementos medianamente incompatibles, todo lo cual sugiere el paso de fundidos metasomáticos de naturaleza silicatada alcalina rica en carbónico. Este mismo metasomatismo afectaría a algunos xenolitos lherzolíticos con espectros similares., In xenoliths from the Los Tormos volcano (Calatrava volcanic field), two main mantle xenolithic groups have been distinguished according to modal analysis, amphibole occurrence and clinopyroxene chemical composition. These features suggest different origins for each xenolith group, evidencing mantle sectors metasomatized by different agents. The spinel-bearing lherzolite xenoliths define the most abundant group, showing high magnesium and low trace-element contents in the rock-forming minerals, with nearly flat clinopyroxene trace element pattern, suggesting affinity to depleted mantle sources (MORB type). The well-pronounced Nb-Ta negative anomaly in these patterns indicates later variable interaction with subduction-related metasomatic agents. The amphibole-bearing wehrlite group shows Fe-rich mineralogy and clinopyroxene normalized trace-element spectra enriched in the most incompatible elements, defining typical metasomatism by carbonate-rich silica under-saturated alkaline melt. The other xenoliths showing similar trace element patterns than hydrous wehrlites are also affected by silica-undersaturated alkaline metasomatism., Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

This work reports petrographical, mineralogical and geochemical data of a suite of mantle xenoliths from the Morrón de Villamayor volcanic centre (MVM), which belongs to the Calatrava Volcanic Field (CVF), a part of the Circum-Mediterranean Anorogenic Cenozoic Igneous Province. The MVM volcano is the only centre belonging to the first stage of the CVF magmatism, an ultrapotassic stage that provides a sampling of the subcontinental lithospheric mantle beneath central Spain. The MVM peridotites record a variable host melt interaction (spongy texture and reaction zones), more intense toward xenolith-host leucitite contacts that it was formed during transport within the volcanic melt. The studied mantle xenoliths are spinel lherzolites equilibrated at lower temperatures (618–942 °C) and similar pressure ranges (8.8–13.6 kbar) than other studied CVF mantle xenoliths, and record a lithospheric mantle before the main volcanic Calatrava event. The MVM lherzolites could be classified in two groups by their chondrite-normalized rare earth element (REE) clinopyroxene patterns: group-1 lherzolites show flat pattern, and group-2 lherzolites display a LREE-depleted (N-MORB like) pattern. Group-1 lherzolites represent a more residual lithospheric mantle (up to 9 partial melting %) than group-2 lherzolites (~ 5%), the latter with similar partial melting degrees than other mantle xenoliths from the CVF. Moreover, group-1 lherzolites have undergone a post partial melting refertilization by different metasomatic agents: silicate and alkaline silicate melts different in composition to host leucitite. A primary clinopyroxene concentrate from these MVM lherzolites provides high Sr (87Sr/86Sr = 0.706104) and intermediate Nd (143Nd/144Nd = 0.512830) initial radiogenic ratios, not previously recorded in this volcanic field. This sampling proves the presence of an enriched isotope mantle pole in xenolith suites of the Calatrava area, trending in composition to an intermediate DMM-EMII compon, Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

Alkaline volcanic rocks from explosive monogenetic centers often carry an unusual cargo of crystals and rock fragments, which may provide valuable constraints on magma source, ascent and eruption. One of such examples is the Cenozoic Calatrava Volcanic Field in central Spain, a still poorly explored area to address these issues. Clinopyroxene, amphibole and phlogopite appear either as megacryst/phenocrysts or forming fine-grained cumulates (pyroxenite enclaves s.l.) in some eruptive centers of this volcanic field. They have previously been interpreted as cogenetic high-P minerals formed within the upper lithospheric mantle. The presence of Fe-Na-rich green and Mg-Cr-rich colorless clinopyroxene types as phenocryst cores or as oscillatory zoned crystals in pyroxenite enclaves points to a complex evolution of mineral fractionates from petrogenetically related magmas. In trace element chemistry all studied clinopyroxene types show parallel rare earth element patterns irrespective of whether they are megacrysts, colorless or green core phenocrysts, or zoned crystals within pyroxenite cumulates. This similarity indicates a genetic relationship between all the fractionated minerals. This is in agreement with the overlapping of initial 143Nd/144Nd and 87Sr/86Sr ratios of pyroxenite enclaves (0.512793–0.512885 and 0.703268–0.703778) that is within the chemical field of the host magmas and the Calatrava volcanics. The initial 143Nd/144Nd and 87Sr/86Sr ratios of megacrystic clinopyroxene, amphibole and phlogopite show a more restricted range (0.512832–0.512890 and 0.703217–0.703466), also falling within the isotopic composition of the Calatrava volcanic rocks. Deep magmatic systems beneath monogenetic volcanic fields involve several stages of melt accumulation, fractionation and contamination at variable depths. Trace element and isotope mineral chemistry are powerful tools to understand the history of ascent and stagnation of alkaline basaltic magmas and discriminate between, Ministerio de Economía y Competitividad (MINECO), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

The El Morrón de Villamayor (MVM) peridote xenoliths vary from orthopyroxene-poor lherzolite to wehrlite in modal composition. This compositional feature contrasts with other Calatrava (CVF) xenolith suites. The studied xenoliths equilibrated at lower temperatures (618-942 o C) and slightly shallower (8.8-13.6 kbar) conditions than other CVF peridotites. MVM peridotites show local intense interaction with the host leucitite displaying spongy rims around primary clinopyroxene and also reaction zones with K-rich minerals (e.g., sanidine, leucite and richterite) and widespread clinopyroxene, olivine and spinel neoblasts. Nevertheless, the orthopyroxene-poor character of MVM peridotites might be caused by some previous metasomatic event., Los xenolitos peridotíticos del volcán El Morrón de Villamayor (MVM) son lherzolitas pobres en ortopiroxeno y wehrlitas, en contraste con los datos previos de xenolitos de otros volcanes de Calatrava. Las peridotitas estudiadas están equilibradas a temperaturas más bajas (618-942 o C) y menor profundidad (8,8-13,6 kbar) que las estimadas en otras peridotitas del Campo Volcánico de Calatrava. Localmente hay una intensa interacción del fundido leucitítico con los minerales primarios de la peridotita, ya que se originan zonas de reacción con minerales ricos en K (p.ej., sanidina, leucita y richterita) y frecuentes neoblastos de clinopiroxeno, olivino y espinela. El carácter pobre en ortopiroxeno de las peridotitas MVM debe estar causado por algún evento metasomático previo, Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s4151 3-019-00101 -3) contains supplementary material, which is available to authorized users., Megacristales de clinopiroxeno, anfíbol y flogopita aparecen en los depósitos piroclásticos ricos en cristales, enclaves y xenolitos, de los volcanes de El Aprisco y Cerro Pelado (campo volcánico de Calatrava). Estos megacristales muestran una composición química similar a los cristales que forman los enclaves clinopiroxeníticos asociados, incluyendo los poco comunes enclaves ricos en flogopita (glimmeritas). El magma volcánico es de textura porfídica, mostrando una compleja población de fenocristales y macrocristales máficos, con núcleos residuales, que sugieren formen una suite cogenética con aquellos. Las estimaciones geobarométricas indican que los megacristales, así como los núcleos de fenocristales y los enclaves clinopiroxeníticos representan acumulados de alta presión, formados entre 12–16 kbar, en el manto litosférico superior (de 35 a 55 km). La variabilidad composicional de estos minerales máficos apunta a un proceso de diferenciación controlado por la cristalización de olivino, clinopiroxeno, anfíbol y flogopita. La cristalización de minerales máficos hidratados en el manto facilitaría la exsolución de CO2 y la subsecuente ebullición del fundido, posibilitando la fragmentación de los márgenes semicristalinos de la cámara magmática y la excavación de la roca mantélica encajante. Esta fragmentación profunda explicaría también la compleja variedad de cristales, enclaves y xenolitos atrapados por los magmas volcánicos. Se han encontrado dos tipos de clinopiroxenos (verde e incoloro) que aparecen como antecristales (núcleos de macrocristales/fenocristales) y también en los enclaves piroxeníticos. La coexistencia de ambos tipos de clinopiroxeno en los zonados cristalinos de las clinopyroxenitas sugiere que deben ser cogenéticos, representando precipitados de fundidos de distinto grado evolutivo, pero posiblemente de un mismo magma fraccionante. Este estudio propone un modelo de ascenso y origen de magmas ricos en cristales y xenolitos que puede ser útil para e, Clinopyroxene, amphibole and phlogopite megacrysts appear in the crystal- and xenolith-rich pyroclastic deposits of the Cerro Pelado and the El Aprisco volcanoes (Calatrava volcanic field). These megacrysts display a similar composition to crystals forming clinopyroxenite and rare phlogopite-rich (glimmerite) enclaves. The host magmas are highly porphyritic, showing a complex population of mafic macrocrysts and phenocryst cores. Most of these crystals are chemically similar, suggesting that they constitute a cogenetic suite of phenocrystic origin. Geobarometric estimations indicate that megacrysts and enclaves represent high-P cumulates, mostly formed at about 12–16 kbar within the upper lithospheric mantle (35 to 55 km). The compositional variability of the analyzed minerals indicates a differentiation process controlled by fractionation of olivine, clinopyroxene, amphibole and phlogopite. The crystallization of hydrous mafic minerals at mantle depths facilitated CO2 exsolution and subsequent boiling of the host magma, thus triggering the fragmentation of the semi-crystallized margin of the magma chamber and the excavation of mantle wall-rocks. This deep fragmentation could also explain the complex variety of crystals, enclaves and xenoliths dragged by the volcanic magmas. Two clinopyroxene types (green and colourless) have been found, both as antecrysts (macrocryst/phenocryst cores) and within enclaves. The coexistence of these clinopyroxenes within zoned crystals in clinopyroxenites suggests that they might be cognate, representing primitive and evolved products of a single fractionating magma. This study provides a model for the ascent of crystal- and xenolith-rich magmas that could be regarded in other alkaline volcanics carrying complex crystal cargos from the Cenozoic circum-Mediterranean area., Ministerio de Economía y Competitividad (MINECO), Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

Ministerio de Economía y Competitividad (MINECO), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

We present here a comprehensive and updated review on the gneissic Ollo de Sapo Formation (OSF) in the Iberian Massif and discuss multiple aspects (lithostratigraphy, petrography, geochemistry, geochronology, and partial melting relationships) of its evolution through time. These aspects arise from the superposition of a multi-magmatic Cambro-Ordovician assemblage and a complex Variscan metamorphic overprint. The OSF comprises plutonic, subvolcanic, volcanic, and volcaniclastic units of fel and peraluminous compositions and calcalkaline affinity of the Upper Cambrian to the Lower Ordovician age (495–470 Ma), which crops out at the core of a 600-km-long antiform in the Ollo de Sapo Domain of the Iberian Massif and are overlain by the Armorican Quartzite. The most striking petrographic features of the OSF are the large phenocrysts of K-feldspar, plagioclase, and blue quartz, giving the name “Ollo de Sapo” (toad's eyes), and the large fraction of inherited zircons of Ediacaran or older ages. Geochemical and petrographic indicators point to a medium-P, high-T melting event of Neoproterozoic metasedimentary rocks, most probably the Schist and Greywacke Complex, and a subsequent rapid ascent of melts. Augen gneisses of mostly plutonic origin, of similar age, petrography, and geochemistry and emplaced in the same sedimentary sequences in the Iberian Massif but in lower stratigraphic levels than the classical Ollo de Sapo Domain, also exist. These plutonic augen gneisses are considered to be genetically related to the OSF. The magmatic event that produced the OSF and the equivalent augen gneisses in the Iberian Massif, as well as other augen gneisses present in the European Variscan Belts, has been supposedly related to the opening of the Rheic Ocean in the northern margin of Gondwana. The Variscan metamorphism affected the OSF and the equivalent augen gneisses to variable degrees, from low-grade to anatectic conditions, in a clockwise P-T-t path, that produced its characte, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

El volcanismo alcalino se caracteriza porque frecuentemente es portador de xenolitos procedentes del manto. En el campo volcánico de Calatrava, donde varios centenares de volcanes monogénicos de magmas alcalinos y ultralcalinos han sido identificados, se han encontrado en varios de ellos lavas o piroclastos que incluyen estos xenolitos peridotíticos. En el volcán Los Tormos de Pozuelo de Calatrava, que dio lugar a un cono de escorias, también aparecen frecuentes xenolitos de peridotitas, hasta ahora no estudiados. El conjunto de estos xenolitos proporcionan una información valiosa sobre el manto litosférico y, por tanto, el estudio de éstos permitiría aumentar el conocimiento del mismo en el sector correspondiente al centro de la península Ibérica. El muestreo de los xenolitos peridotíticos en el volcán Los Tormos corresponde en su mayoría a lherzolitas, un número menor de harzburgitas y sólo se ha encontrado una wehrlita. La fase alumínica presente en todos ellos es la espinela, que concuerda con las estimaciones de presión (10-15.2 kbar) y temperatura (961-1185 ºC) obtenidas en base a la composición química de fases minerales en equilibrio, y que indican que pertenecen al campo de estabilidad de peridotitas con espinela, con profundidades de 35-55 km. Los modelos de fusión obtenidos a partir de la composición química (estimada) de elementos mayores de roca total y de los minerales primarios de la peridotita (ortopiroxeno, clinopiroxeno, espinela y olivino) muestran un bajo grado de fusión parcial para las lherzolitas (hasta un 10 %) y un mayor grado de fusión (hasta un 15 %) para las harzburgitas. La wehrlita, en cambio, por el bajo Mg# (0.83 – 0.87) de los olivinos en comparación con el de los otros xenolitos, asi como por su composición química estimada (roca total), que no sigue la tendencia de empobrecimiento del manto primordial sino que es más fértil que éste, indica que se trataría de un residuo de fusión parcial que sufrió metasomatismo debido a la interac

Unión Europea. FP7, Ministerio de Economía y Competitividad (MINECO), Universidad Complutense de Madrid/Banco de Santander, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

© C. Villaseca, V.C. Ruíz-Martínez, C. Pérez-Soba, 2017 We thank Alfredo Fernandez Larios for his assistance with the electron microprobe analyses in the Centro Nacional de Microscopia Electronica Luis Bru (UCM). Comments and revision of an early version of the work by Dr. Encarnacion Roda-Robles were very fruitful. We also thank the comments and suggestions made by Montserrat Liesa (Editor) and two anonymous reviewers that greatly increased the quality of the manuscript. This work is included in the objectives and supported by the CGL2016-78796 project of the Spanish MICINN and the Santander-UCM PR26/16-20294 project., Magnetic susceptibility (MS) has been measured in Variscan granites from central Spain. They yield values in the order of 15 to 180 mu SI units for S-and I-type granites, indicating that both types belong to the ilmenite series. Only samples from magnetite-bearing leucogranites from the I-type La Pedriza massif show high MS values, in the order of 500-1400 mu SI, reflecting the presence of this ferromagnetic mineral. Mineral chemistry of magmatic Fe-rich minerals (mainly biotite) suggests similar oxidation values for both granite types. MS values change in highly fractionated granites accordingly either with the presence of rare new Fe-oxide phases (some I-type leucogranites) or with the marked modal amount decrease of Fe-rich minerals (I-and S-type leucogranites). The redox state in highly fractionated granite melts is mostly controlled by magmatic processes that modify redox conditions inherited from the source region. Thus, the occurrence of magnetite or ilmenite in granites is primarily controlled by the oxidation state of the source material but also by the differentiation degree of the granite melt. The presence of magnetite in some Variscan I-type leucogranites might be a consequence of crystal fractionation processes in a more limited mafic mineral assemblage than in S-type granite melts., Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid/Banco de Santander, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

El documento expone brevemente los objetivos, metodología y resultados de un proyecto de innovación docente dedicado a continuar con el desarrollo de una página web para el aprendizaje de aspectos prácticos de petrología ígnea. Este proyecto es la continuación de otro desarrollado durante la convocatoria 2013. La página web creada, denominada ATLAS DE ROCAS ÍGNEAS (http://petroignea.wordpress.com), incluye fotografías de muestras de mano, imágenes de microscopio y de afloramiento de rocas ígneas, así como breves explicaciones de las características principales que se aprecian en dichas imágenes. También se introducen conceptos sobre la clasificación de las rocas ígneas. El proyecto de la convocatoria de 2014 se ha centrado más específicamente en desarrollar aspectos meso y macroscópicos relacionados con la manera en la que se disponen las rocas ígneas en la naturaleza en forma de depósitos más o menos grandes. Para ello, además de fotografías de campo, se han incluido esquemas, diagramas, mapas geológicos o imágenes de satélite. Esta página es de libre acceso y cuenta ya con una notable afluencia de visitantes.

Ministerio de Economía y Competitividad (MINECO), Universidad Complutense de Madrid, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, FALSE, pub

Major and trace element chemistry has been determined in the main minerals (olivine, orthopyroxene, clinopyroxene, plagioclase, amphibole, phlogopite) from the Talavera and La Solanilla gabbroic intrusions (Spanish Central System). The results show a heterogeneous mineral composition illustrative of the chemical evolution of calc-alkaline basic magmas during crystallization. The formation of incompatible element-rich interstitial minerals, such as amphibole, phlogopite and accessory phases (e.g., zircon, apatite), and the presence of zoning patterns in major minerals towards a more evolved composition, point to a progressive differentiation of the parental melt. The chemical variation depicted by trace elements usually incompatible with clinopyroxene (e.g., rare earth elements (REE), Th, Zr, Nb, Ti) implies co-precipitation with phases displaying a compatible behaviour with respect to these elements (e.g., apatite, zircon, amphibole). However, the very high LILE (large ion lithophile elements) and LREE (light REE) shown by clinopyroxene can not be explained exclusively by a closed-system in-situ crystallization process. Several features of the mineral chemistry (e.g. positive correlation of (La/Sm)N with La and Na in clinopyroxene and plagioclase, respectively) support the involvement of an external component (wall-rock assimilation or hybridization with an evolved melt). The petrography and mineral chemistry of the gabbros, in conjunction with bulk rock data from previous studies, favour a calc-alkaline affinity for the parental melts. Thus, metasomatism in the mantle sources related with this basic magmatism might be associated with recycling of crustal components during the Variscan orogeny., Se ha caracterizado la composición química de elementos mayoritarios y trazas en los minerales principales de las intrusiones gabroideas de Talavera y La Solanilla (Sistema Central Español). Los resultados muestran una composición mineral heterogénea que es ilustrativa de una evolución química de los magmas básicos calco-alcalinos durante la cristalización. La formación de minerales intersticiales con elevados contenidos en elementos incompatibles, como por ejemplo el anfíbol, la flogopita y algunos minerales accesorios (circón, apatito...), y la presencia de zonados en los minerales principales, con tendencia a desarrollar una composición más evolucionada hacia el borde, indican la diferenciación progresiva del fundido parental. La variación química de elementos traza normalmente incompatibles en el clinopiroxeno (e.g., REE, Th, Zr, Nb, Ti) implica la co-precipitación de fases con un comportamiento compatible con dichos elementos (e.g., apatito, circón, anfíbol). Sin embargo, las elevadas concentraciones de LILE y LREE del clinopiroxeno no se pueden explicar exclusivamente por un proceso de cristalización en un sistema cerrado. Varias características de la química mineral (e.g., correlación positiva de la relación (La/ Sm)N con el contenido de La y Na en el clinopiroxeno y la plagioclasa, respectivamente) suponen la participación de un componente externo (asimilación de roca encajante o mezcla con un fundido más evolucionado). La petrografía y la química mineral de los gabros, junto con los datos de roca total de estudios previos, favorece una afinidad calco-alcalina para los fundidos parentales. Por lo tanto, el metasomatismo en las fuentes de manto asociadas con este magmatismo básico podría estar relacionado con el reciclaje de componentes corticales durante la orogenia Varisca., Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub