Spilites, regional metamorphism and subduction in the Iberian Pyrite Belt: some somments

Abstract

The Devonian-Lower Carboniferous eugeosynclinal succession of the lberian Pyrite Belt was deformed and regionally metamorphosed during the Hercynian orogeny. Metamorphic grade decreases from lower greenschist facies in the north to pumpellyite facies in the south. The volcanics comprise a felsic and a mafic-intermediate suite, the latter including spilite lavas and tuffs with intrusive diabases. Spilites precede, follow, and are contemporaneous with felsic eruptions. The parent magma of the spilites and albite diabases was not altered notably by contamination and assimilation. The felsic volcanics are sodic to potassic quartz keratophyres, mostly tuffs. Rio Tinto stratigraphy is reviewed. The possibility that the compositional bimodality of the volcanics might be related to subduction seems remote.