Publication: Petrogenesis of Ordovician Magmatism in the Pyrenees (Albera and
Canigó Massifs) Determined on the Basis of Zircon Minor
and Trace Element Composition
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Publication Date
2011
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University of Chicago Press
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Abstract
Zircon composition (U, Th, rare earth elements, and Hf) was tested as a tracer of petrogenetic processes in a set of
metaigneous rocks from two pre-Ordovician massifs in the Pyrenees, Canigo´ and Albera. Two groups were differentiated
after analyzing a number of elements in zircon: (1) Casemı´ gneiss and Marialles amphibolite and (2) subvolcanic
metaporphyries and Cadı´ and Sureda orthogneisses. Casemı´ gneiss and Marialles amphibolite from the Canigo´
massif have high Th, Th/U, and Ce/Sm and low Yb/Gd and U/Ce that define linear trends in most of the plots used.
The anomalous trend of the data in the Th/U-versus-Hf plot suggests mantle involvement in the origin of these rocks
and the participation of fractional crystallization during their evolution. Zircon of the metaporphyries and the Cadı´
and Sureda orthogneisses exhibit similar characteristics despite a difference in age. Zircon has low Th, Th/U, Ce/
Sm, and and high Yb/Gd and U/Ce, suggesting that this mineral grew in a melt formed by anatexis of a ∗ Eu/Eu
continental crust, with stable plagioclase. These petrogenetic data are consistent with the previously studied wholerock
geochemistry and Sr-Nd isotopes and confirmthe use of zircon as a marker of petrogenetic processes in preference
to a lithological tracer.