Person:
Galindo Francisco, María Del Carmen

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First Name
María Del Carmen
Last Name
Galindo Francisco
URI
https://hdl.handle.net/20.500.14352/81297
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
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Subject: 550.93(82) ×

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    Síntesis geocronológica de la evolución paleozoica inferior del borde sur occidental de Gondwana en las Sierras Pampeanas, Argentina
    (Acta geológica hispánica, 1997) Baldo, Edgardo G.; Saavedra, Julio; Rapela, Carlos W.; Pankhurst, R.J.; Casquet Martín, César; Galindo Francisco, María Del Carmen
    Las Sierras Pampeanas Argentinas constituyen un buen registro de la evolución Pre-Devónica del margen sur occidental del Gondwana. Los trabajos multidisciplinarios recientes y especialmente la información geocronológica, recolectada a lo largo de una transecta E-W de aproximadamente unos 500 km, permiten precisar la edad y los rasgos geológicos de los dos principales ciclos tectono-magmáticos involucrados en la evolución paleozoica inferior de esta parte del basamento argentino. El Ciclo Orogénico Pampeano comienza con una etapa de sedimentación en un margen pasivo (560-530 Ma), que evoluciona hacia una situación de margen activo con generación de un arco magmático tipo Andino, a los 533 - 528 Ma. El ciclo finaliza hacia los 523 Ma. en una colisión de tipo ortogonal, con un importante engrosamiento cortical, anatexis regional y generación de granitos "S". El "Ciclo Orogénico Famatiniano" se inicia a los 499-496 Ma y se caracteriza por la implantación de un arco magmático intemo de tipo trondhjemitico, seguido hacia el oeste por un importante arco magmático externo, contemporáneo con el anterior y formado por granodioritas de tipo "1" y grandes batolitos graníticos de tipo "S". Durante el Famatiniano tiene también lugar la formación de una cuenca de retroarco ensiálica con magmatismo básico. El final de este ciclo (450-420 Ma) está marcado por el desarrollo de importantes fajas de milonitización que marcan la colisión oblicua del Terreno Precordillera respecto al margen de Gondwana
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    Geoquímica isotópica (Sr y Nd) de las anortositas (“massif type anorthosites”) grenvillianas de las Sierras Pampeanas Occidentales (Argentina). Fuentes magmáticas e implicaciones geotectónicas
    (Geociencias, recursos y patrimonio geológicos : 30º Aniversario del Comité Nacional Español / Programa Internacional de Geociencias (PICG/IGCP), 2005) Casquet Martín, César; Galindo Francisco, María Del Carmen; Rapela, Carlos W.; Pankhurst, R.J.; Baldo, Edgardo G.; Dahlquist, Juan A.; Fanning, C.M.; González Casado, José Manuel; Saavedra, Julio; Lamolda, Marcos A.
    Massif-type anorthosites are igneous complexes that consist for the most part of anorthosite, a plagioclase- rich plutonic rock. They are particularly abundant within or near the worldwide Grenvillian mobile belt (1.0-1.2Ga), which resulted from the assembly of the Mesoproterozoic supercontinent of Rodinia. In two of the most western Sierras Pampeanas (Sierras of Maz and Espinal, NW of Argentina), two anorthositic igneous complexes have been discovered recently (Casquet et al. 2005a). Coarse-grained anorthosites is the predominant rock type in these complexes. The age of crystallization is of 1070 ± 41 Ma (U-Pb SHRIMP, in zircons). These rocks have a superposed regional metamorphism of Ordovician age (431±30 Ma; U-Pb SHRIMP, in zircons). These complexes are the only ones mentioned in Argentina and are the first of recognized Grenvillian age in Sudamerica. Nd and Sr isotope composition suggest that primary magmas derived from a depleted source. Moreover moderate contamination with an enriched continental component is also inferred. Nd model ages suggest that the depleted source formed coeval with the anorthosite magmatism, which is compatible with a mantle plume probably related to the early break up of Rodinia.
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    New geochronological and isotope data for the Las Chacras – Potrerillos and Renca batholiths: A contribution to the Middle-Upper Devonian magmatism in the pre-Andean foreland (Sierras Pampeanas, Argentina), SW Gondwana
    (Journal of South American Earth Sciences, 2019) Dahlquist, Juan Andrés; Macchioli Grande, Marcos; Alasino, Pablo H.; Basei, Miguel A.S.; Galindo Francisco, María Del Carmen; Moreno Moreno, Juan Antonio; Morales Cámera, Matías M.
    The Las Chacras-Potrerillos together with the Renca batholith (Sierras de San Luis) are the largest Devonian igneous bodies in the Sierras Pampeanas after the Achala batholith (Sierra de Córdoba), all emplaced in the Devonian foreland region. The Achala batholith has U–Pb zircon ages (using SHRIMP or LA-ICP-MS methodology, ranging from 366 to 379 Ma), while comparable ages for the Las Chacras-Potrerillos batholith remain absent (a single U–Pb conventional zircon age is available for this batholith), and one weighted mean age (U–Pb zircon SHRIMP data) is available for Renca batholith. U–Pb zircon LA-MC-ICP-MS data sets from a monzogranite sample of the biotite-amphibole porphyritic granite unit (CHA-101), the largest granitic unit of the Las Chacras-Potrerillos batholith, yielded three ages: 377 ± 3, 384 ± 2, and 393 ± 3 Ma. These ages (outside error limits), suggest the existence of a long-lived magmatic plumbing system, of around 15 Ma, with intrusion of younger batches into older crystal mushes. This interpretation leads us to assume a long period of heating in the source through the earliest Middle - early Upper Devonian ranging from 377 to 393 Ma. Based on previous studies of ascent and emplacement of granitic magmas, we propose that the majority of the zircon ages measured could be inherited from a deeper level of the magmatic system (i.e., antecrysts) and only some could be assigned to in-situ crystallization during the emplacement in middle-upper crust. Additionally, U–Pb zircon SHRIMP data sets from a monzogranite sample of the biotite-amphibole porphyritic granite unit (REN-103), the largest granitic unit of the Renca batholith, yielded two ages: 353 ± 4 Ma and 393 ± 3 Ma. The older age is equal to that obtained for the CHA-101 sample and confirms that the magmatism started in the earliest Middle Devonian. The younger age is comparable to previous ages determined in micas crystallized in intragranitic pegmatites as well as cooling ages from biotite hosted in granites of the Las Chacras-Potrerillos batholith, strongly suggesting a long-lasting cooling history of ca. 24 or 40 Ma (according to the crystallization age assumed, 377 or 393 Ma) or a reheating effect at around 350 Ma as was suggested in previous works. Recent Carboniferous crystallization ages determined in granites of the Sierras Pampeanas produced similar values (i.e., close to 350 Ma), and suggest a longer time of magmatic activity embracing the Middle-Late Devonian – Early Carboniferous (∼40 Ma), in the Devonian foreland (present-day Eastern Sierras Pampeanas). Nd and Sr isotopes data from CHA-101 and REN-103 samples (εNdt and 87Sr/86Srt ranging from −3.0 to −1.1 and from 0.706861 to 0.707275, respectively), are consistent with previous data reported for the studied granitic units and suggest a continental source with probable participation of subcontinental lithospheric mantle. TDM values (1.2 and 1.4 Ga) support the idea of an older Gondwana lithosphere source for the studied monzogranites.