Metaluminous pyroxene-bearing granulite xenoliths from the lower continental crust in central Spain: their role in the genesis of Hercynian I-type granites
Basic and intermediate meta-igneous xenoliths are very scarce within the granulite population transported by the Permian alkaline lamprophyric dyke swarmof the Spanish Central System(SCS). These xenoliths aremetaluminous pyroxene-bearing charnockites (sensu lato). They show LREE-poor plagioclase and...
| Autores: | , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2007 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/49617 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/49617 |
| Access Level: | acceso abierto |
| Palabra clave: | 552.3(234.1) Granulite xenoliths Pyroxene mineral chemistry Hercynian granites Igneous petrology Lower crust Central Spain Petrología |
| Sumario: | Basic and intermediate meta-igneous xenoliths are very scarce within the granulite population transported by the Permian alkaline lamprophyric dyke swarmof the Spanish Central System(SCS). These xenoliths aremetaluminous pyroxene-bearing charnockites (sensu lato). They show LREE-poor plagioclase and orthopyroxene-clinopyroxene. Crystallization conditions were estimated at about 850 to 1000 ◦C and 9 to 11 kbar, a slightly higher range than that estimated for the associated peraluminous granulites, but indicating derivation from the lowermost crust. Whole-rock geochemistry suggests that the charnockite samples are not a cogenetic suite. The more basic varieties have affinities with cumulates from previous calc-alkaline underplated protoliths, whereas intermediate charnockites have a restitic origin. The similarity in Sr-Nd-Pb isotopic signatures between these restitic charnockites and some SCS I-type granites suggests a genetic relationship. This study, including Pb isotopic data from the whole granulite xenolith suite, reinforces the lower-crustal derivation of the SCS Hercynian granitic batholith. |
|---|