Magmatic Evolution and Tectonic Setting of the Iberian Pyrite Belt Volcanism

Introduction and Geological Setting of the Iberian Pyrite Belt

“…Dacites and rhyolites exhibit an enriched crustal signature based on the Nd and Sr isotopic systematics, consistent with derivation from an older crust (Mitjavila et al 1997). The zircon inheritance provides direct evidence for older (Proterozoic to Ordovician) detrital components in their source rocks (Barrie et al 2002;Rosa et al 2009).…”

“…General syntheses on the IPB include those of Strauss et al (1977), Routhier et al (1980), IGME (1982), Barriga (1990), Sáez et al (1996), Leistel et al (1998), Carvalho et al (1999, Junta de Andalucía (1999), Tornos et al (2000), Tornos (2006). Other general studies deal with stratigraphy (Oliveira 1990;Pereira et al 2007), volcanism (Munhá 1983;Mitjavila et al 1997;Thiéblemont et al 1998), structure and regional metamorphism (e.g., Munhá 1990;Silva et al 1990;Quesada 1998) or the facies architecture of the volcano-sedimentary complex (Soriano and Martí 1999;Junta de Andalucía 1999;Rosa 2007).…”

“…Although subordinate on a regional scale, andesitic lavas also occur (Munhá 1983;Mitjavila et al 1997;Díez-Montes et al 1999). Felsic rocks range from dacite to high-Si rhyolites and belong to a calc-alkaline series.…”

“…The zircon inheritance provides direct evidence for older (Proterozoic to Ordovician) detrital components in their source rocks (Barrie et al 2002;Rosa et al 2009). The diversity of chemical and Sr-Nd isotopic composition of rhyolites, dacites and minor andesites can mainly be explained either by differences in composition of the source rocks or by different degrees of partial melting of upper crust (e.g., Mitjavila et al 1997). Andesites have been interpreted as formed due to contamination (mixing) between basaltic magmas and uppercrust material (Mitjavila et al 1997).…”

“…The diversity of chemical and Sr-Nd isotopic composition of rhyolites, dacites and minor andesites can mainly be explained either by differences in composition of the source rocks or by different degrees of partial melting of upper crust (e.g., Mitjavila et al 1997). Andesites have been interpreted as formed due to contamination (mixing) between basaltic magmas and uppercrust material (Mitjavila et al 1997). The geochemical characteristics of felsic magmatism suggest that they were generated by fractionation/partial melting of amphibolites at low pressures, involving plagioclase and pyroxene in the petrogenetic process without involvement of garnet, and with a significant contamination of crustal material (Díez-Montes and Bellido-Mulas 2008).…”