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Title: | Geochemistry of lower Paleozoic anorogenic basic rocks from the Evora Massif (Western Ossa-Morena Zone, Portugal) |
Other Titles: | Geoquímica de las rocas básicas anorogénicas del Paleozoico inferior del Macizo de Évora (domínios occidentales de la zona de Ossa-Morena, Portugal) |
Author: | Pereira, M. F. Chichorro, M. Santos, J. F. Moita, P. Silva, J. B. |
Keywords: | Geochemistry Anorogenic basic rocks Lower Paleozoic series Évora massif Ossa-Morena zone Rift-related basic rocks Geoquímica Rocas básicas anorogenicas Series del Paleozoico inferior Macizo de Evora Zona de Ossa-Morena |
Issue Date: | 2004 |
Publisher: | Sociedad Geológica de España |
Abstract: | Basic rocks included in the Ossa-Morena westernmost domains (Alentejo region, Portugal) have been studied in an attempt to fill the lack of geochemical data for the Evora Massif. The selected outcrops, interpreted to belong to the Lower Paleozoic stratigraphic record, are mainly represented by amphibolites associated with metamorphosed detritic, carbonate and volcanic-sedimentary series. According to their petrography and variations of major, trace and REE elements, these basic rocks show a basaltic subalkaline tholeiitic character, plot in the within-plate and MORB fields typical of rift-related geodynamic settings. Variations of major, trace and REE elements suggest a variably enriched, heterogeneous mantle source, which was subjected to important fractionation processes and different melting rates. Rocas básicas de los dominios occidentales de la Zona de Ossa-Morena (Alentejo, Portugal) fueron estudiadas con el objectivo de colmatar la falta de datos geoquímicos del Macizo de Évora. Los afloramientos seleccionados incluyen esencialmente anfibolitas asociadas a series detríticas, carbonatadas y volcanosedimentarias metamorfizadas del Paleozoico Inferior. Los datos petrográficos y las variaciones observadas en los elementos mayores, trazo y REE de las rocas básicas indican que son basaltos subalcalinos de carácter toleítico, proyectadas en los campos intra-placa y MORB típicos de ambientes geodinámicos de rifting. Las variaciones observadas en los elementos mayores, trazo y REE son explicadas por una fuente mantélica heterogénea variablemente enriquecida a importantes procesos de fraccionacíon y distintas tasas de fusión. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/13838 |
ISSN: | 0213-683X |
Publisher Version: | http://www.sociedadgeologica.es/archivos/geogacetas/Geo35/Art22.pdf |
Appears in Collections: | DGeo - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Pereiraetal2004.pdf | Documento publicado | 487.83 kB | Adobe PDF | View/Open |
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