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Plutón La Costa, una expresión de magmatismo tipo-s en el sector noreste de la Sierra de Velasco, Sierras Pampeanas
| Content Provider | Semantic Scholar |
|---|---|
| Author | Alasino, Pablo Horacio Dahlquist, Juan A. Francisco, Mª del Carmen Galindo Casquet, César |
| Copyright Year | 2006 |
| Abstract | Estudios combinados de petrologia, quimica mineral y geoquimcia de roca total revelan la presencia de dos unidades graniticas peraluminosas con minerales aluminosos magmaticos tales como granate y mica blanca y la presencia distintiva de turmalina. Las evidencias aqui presentadas indican que estas dos facies, Anillaco y Anjullon, junto a la unidad peraluminosa Santa Cruz estudiada en trabajos previos, constituyen una serie de rocas co-sanguineas, emplazadas en niveles someros de la corteza y las cuales conforman una unidad ignea mayor denominada aqui pluton La Costa, la cual aflora en el sector noreste de la sierra de Velasco. La asociacion mineral, la quimica mineral y la geoquimica de roca total permiten definir al pluton La Costa como un clasico granitoide tipo–S, derivado de una roca fuente de composicion esencialmente pelitica. Diferentes estudios demuestran que la generacion de granitoides tipo-S requiere de un alto gradiente geotermico, por lo cual el pluton La Costa indica que la corteza en esta region soporto un notable calentamiento durante la generacion del magma. Sin embargo, la ausencia de datos geocronologicos impide definir el evento tectomagmatico que produjo el magma primordial de este pluton. [ABSTRACTS] La Costa pluton, an expresion of S- type magmatism in the northeastern sector of the Sierra de Velasco, Sierras Pampeanas. Combined petrology, mineral chemistry and whole-rock geochemistry studies reveal the presence of two peraluminous granitic units with magmatic aluminous minerals, such as garnet and white mica, and the distinctive presence of tourmaline. The evidence presented here indicates that these two facies, Anillaco and Anjullon, together with the peraluminous Santa Cruz unit studied in previous works, constitute co-sanguineous rocks, emplacemed in shallow levels of the crust, conforming a greater igneous unit, named here as La Costa pluton, that outcrops in the northeast sector of the sierra de Velasco. The mineral assemblage, the mineral chemistry and the whole-rock geochemistry allow defining the La Costa pluton as classic S-type granitoids, derived of a source rock of dominant pelitic composition. Several studies demonstrate that a high geothermal gradient is required for the generation of S-types granitoids, thus the La Costa pluton indicates that the crust supported a remarkable heating in this region during the generation of the magma. However, the absence of geochronological data prevents identification of the tectomagmatic event that yielded the parental magma of this pluton. |
| Starting Page | 161 |
| Ending Page | 170 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| Volume Number | 61 |
| Alternate Webpage(s) | http://www.scielo.org.ar/pdf/raga/v61n2/v61n2a02.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
