Person: Galindo Francisco, María Del Carmen
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First Name
María Del Carmen
Last Name
Galindo Francisco
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
4 results
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Item Episienitas de la Sierra de Guadarrama: un proceso hidrotermal regional de edad Pérmico Inferior ligado al inicio de la extensión alpina(Cuadernos de geología ibérica, 1996) Caballero, José María; González Casado, José Manuel; Casquet Martín, César; Galindo Francisco, María Del Carmen; Tornos Arroyo, FernandoLas episienitas de la Sierra de Guadarrama (Sistema Central español), las cuales son resultado de la alteración hidrotermal (decuarcificación y alcalinización) de granitoides, constituyen un conjunto litológico desarrollado en el Pérmico Inferior, con un carácter básicamente isócrono (277 Ma), a escala regional. Estructuralmente definen un marco geodinámico extensional, con dirección de extensión preferente NNE-SSO para este sector del basamento hercínico. Este régimen extensional, asociado a gradientes geotérmicos anormalmente altos, se enmarca en el comienzo de la distensión Alpina (rifting). Ello se debe a la detección en este sector de la Cadena Hercínica de una tectónica de desgarres previa, con una edad comprendida entre 300 y 290 Ma, y que es, a su vez, posterior a los episodios extensionales tardihercínicos asociados al colapso gravitacional de la cadena colisional. Esta etapa de desgarres corresponde a la etapaItem Miarolas del plutón de La Cabrera (Madrid). Clasificación y geocronología de los rellenos hidrotermales(Geotemas, 2004) Lozano, Rafael Pablo; Casquet Martín, César; Galindo Francisco, María Del Carmen; González Laguna, R.A large part of the hydrothermal processes that took place in the Sierra of Guadarrama in the last 300 Ma, are recorded in the infillings of miarolitic cavities that are common in the La Cabrera granitic pluton. Ca-rich minerals such as epidote, prehnite, laumontite, and hexagonal calcite, and to a smaller extent K minerals (muscovite, microcline and apophyllite) are abudant in these cavities and resulted from protracted hydrothermal activity. The miarolitic cavities have been classified in four types: a) cavities with calcic minerals (epidote, prehnite, laumontite and hexagonal calcite), b) cavities with K minerals (muscovite and microcline), c) mixed cavities and d) cavities with quartz, clorite (Mg) and pyrite. Model ages (87Sr/86Sr) of epidote, microcline and apophyllite are 278±18, 143±0.5 and 8.47 Ma, respectively. K/Ar ages of four microdines are 141 ±4, 142±4, 119±3 and 102±9 Ma, and one apophyllite has given 10±2.0 Ma. Epidote model ages are coincident with the age of episyenites and that of some barren quartz veins. Microcline ages match those of some F-Pb-Ba lodes and of younger barren quartz veins. Apophyllite formation is correlated with the recent uplift of the Sierra of Guadarrama.Item Magmatic evolution of the Peñón Rosado granite: Petrogenesis of garnet-bearing granitoids(Lithos, 1995) Dahlquist, Juan A.; Galindo Francisco, María Del Carmen; Pankhurst, R.J.; Rapela, Carlos W.; Alasino, Pablo H.; Saavedra, Julio; Fanning, C.M.Garnet is an uncommon accessory mineral in igneous rocks but is petrologically significant. The Peñón Rosado granite (469± 4Ma) at Cerro Asperecito is an S-type granite that contains an unusual amount of magmatic garnet. Combined petrology, chemistry/ mineralogy and whole-rock geochemistry indicates that the magma was produced by partial melting of the surrounding metasedimentary rocks and subsequent differentiation by fractional crystallization during emplacement, with garnet occurring throughout the crystallization sequence. Three facies are recognised: PRG1 (SiO2=65.70%) represents cumulates, PRG2 (SiO2=70.88%) represents a differentiated melt, and PRG3 (SiO2=74.59%) a residual melt. The fractionation of Mn in garnet and the proportion of garnet crystallizing are roughly controlled by the evolving composition of the different granitic facies.Geothermobaric calculations reveal an initial crystallization temperature of 764°–792 °Cand a pressure of 5.9–6.0 kb, indicating that the parental magma was emplaced atmiddle crustal depths (∼1920 km) in moderate–low magmatic temperature conditions.Major (CaO, Na2O,K2O) and trace element (Rb, Sr, Ba) contents in the Peñón Rosado granite strongly suggest anatexis was the outcome of H2O-fluxed melting of metagreywacke, with heat input from a major metaluminous suite. Our studies reveal that garnet formed by direct crystallization from peraluminous magma in equilibrium with solid phases such as biotite and white mica.We confirm previous suggestions that zoning in garnet is strongly temperature-dependent. Thus, magmatic garnets in granitic rocks crystallized above ∼ 700 °C have “spessartine inverse bell-shaped profile” or are unzoned, whereas garnet exhibiting “spessartine bell-shaped profile” must be considered of metamorphic origin (i.e., xenocrystic) or formed in very felsic magmas (SiO2=73–76%) crystallizing below ∼ 700 °C. © 2006 Elsevier B.V. All rights reserved.Item Granitoides peraluminosos y su relación con las rocas fuentes(Geogaceta, 2005) Dahlquist, Juan A.; Alasino, Pablo H.; Galindo Francisco, María Del CarmenComparative compositional studies between two peraluminous unit with magmatic andalucite and cordierite indicate that they were produced by partial melting of two differents metasedimentary source rocks. We conclude that geochemical studies from peraluminous unit contributes to define the source rocks and to constrain the pre-orogenic geotectonic environment