Abstract

The La Pedriza pluton stands out as the most extensively fractionated granite (Rb lt; 629; Sr lt; 2 and Ba lt; 2 ppm) of the Spanish Central System Batholith. These granites show a strong enrichment in some rare metal contents (Nb = 44, Y = 136, Yb = 10.7, U = 17, Ta = 7, Sc = 15 ppm). The petrography and geochemistry (including Sr- Nd isotopes) reveal that the pluton is composed of at least four units. These are classified as I-type peraluminous leucogranites (A/CNK=1.03-1.17), P-poor (P2O5lt;0.2 wt%) and Na2O-rich (lt; 4.24 wt%) exhibiting differences in their HFSE and REE contents and εNd compositions. Moreover, the units of the La Pedriza granite display different trends of fractional crystallization. REE spectra of the two most fractionated units suggest the involvement of a fluorine-rich melt in the last stages favouring the crystallization of xenotime and niobotantalates. Intermediate meta-igneous granulite protoliths are proposed as source rocks. The most evolved units of the La Pedriza pluton show chemical features convergent to A-type granites; these are explained by extensive fractional crystallization of a P-poor, I-type granite magma.

Details

Title
Petrogenesis of highly fractionated I-type peraluminous granites: La Pedriza pluton (Spanish Central System)
Author
PÉREZ-SOBA, C; Villaseca, C
Pages
131-149
Section
Articles
Publication year
2010
Publication date
2010
Publisher
Universitat de Barcelona Revistes Cientifiques de la Universitat de Barcelona
ISSN
05677505
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3108240397
Copyright
© 2010. This work is published under https://creativecommons.org/licenses/by-sa/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.