Dataciones Rb/Sr en el complejo anatéctico de la Peña Negra (Batolito de Ávila, España central): evidencias de magmatismo pre-hercínico
- M.D. Pereira 1
- Y. Ronkin 2
- F. Bea 3
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1
Universidad de Salamanca
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2
Zavaritsky Institute of Geology and Geochemistry
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3
Universidad de Granada
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ISSN: 0214-2708
Year of publication: 1992
Volume: 5
Issue: 1-2
Pages: 129-134
Type: Article
More publications in: Revista de la Sociedad Geológica de España
Abstract
A Rb/Sr geochronologic study of the Peña Negra Anatectic Complex (CAPN) has allowed us: 1) To determine the minimum age of the CAPN protolith, made of migmatites and orthogneisses. It gives an age of 528 ± 14 m.a., with initial Sr87 /Sr86 = 0.7071; 2) To determine the age of subautochtonous granodiorites, anatectically developed from the above mentioned protolith. We have obtained an age of 310 ± 6 m.a. This value can also date the most intensive period of the migmatization and the second hercynian deformation phase, both being contemporaneous with the generation of granodiorites. Their initial Sr87 /Sr86 = O. 7096 supports the idea of a hybrid source composed of migmatites and orthogneisses. 3) To identify the existence of a prehercycian basic magmatism, obtaining a 416 ± 21 m.a. age with initial Sr87/Sr86 = 0.7051.