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
3 results
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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 Hf and Nd isotopes in Early Ordovician to Early Carboniferous granites as monitors of crustal growth in the Proto-Andean margin of Gondwana(Gondwana research, 2013) Dahlquist, Juan A.; Pankhurst, R.J.; Gaschnig, Richard M.; Pankhurst, R.J.; Rapela, Carlos W.; Casquet Martín, César; Galindo Francisco, María Del Carmen; Alasino, Pablo H.; Baldo, Edgardo G.Wereport the first study integrating in situ U–Pb and Hf isotope data frommagmatic zircon andwhole-rock Sm–Nd isotope data for granitic rocks of the Sierras Pampeanas, Argentina, in order to evaluate the Palaeozoic growth of the proto-Andean margin of Gondwana. Early–Middle Ordovician granitic magmatism is by far the most voluminous of the Sierras Pampeanas and represents the most significant magmatic event. These calc-alkaline granitoids were intruded at an active continental margin. εHft values range from −3.3 to −14.7 and εNdt from −3.3 to −6.3 (t=473 Ma), with average TDM Hf and TDM Nd ranging from 1.5 to 2.2 Ga and 1.4 to 1.7 Ga, respectively. Middle–Late Devonian magmatism occurred in the foreland, away from the orogenic front in the west, and included F-U-REE rich A-type granites. The Achala granite, the largest batholith in the Sierras Pampeanas, has εHft and εNdt values ranging from −3.6 to −5.8 and −4.0 to −6.5, respectively (t=369 Ma). Small scattered Early Carboniferous A-type granite plutons were intruded in a dominantly extensional setting and have εHft and εNdt values ranging from−6.7 to+2.2 and−0.5 to−3.6, respectively (t=341 Ma). The generation of Ordovician and Devonian magmas dominantly involved crustal reworking and stabilization rather than the formation of new continental crust by juvenile material accretion, whereas carboniferous magmatism resulted in part from reworking of supracrustal material, but with variable addition of juvenile magmas.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