Publication: Composición isotópica de Lu–Hf en circones de las etabasitas ordovícicas del Sistema Central Español
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Publication Date
2019
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Sociedad Geológica de España
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Abstract
La composición isotópica Lu-Hf de los circones de las metabasitas ordovícicas del Sistema Central Español proporciona valores entre ligeramente y moderadamente empobrecidos y señala diferencias entre el sector de Tenzuela y los de Revenga-El Caloco. Los metagabros de estos últimos sectores poseen un ligero desajuste entre los valores de εHf y εNd (εHf por encima de la alineación del manto), así como edades modelo de Hf y Nd mayores. Esta característica probablemente implica que cierto reciclaje de sedimentos pelágicos se produjo dentro del área fuente mantélica de las metabasitas de Revenga-El Caloco durante el ciclo orogénico Cadomiense. La semejanza isotópica respecto a materiales básicos variscos parece indicar que el manto bajo el Sistema Central Español no se rejuveneció ni experimentó cambios importantes desde el Ordovícico hasta el final de la orogenia Varisca.
The zircon Lu-Hf isotopic composition of the Ordovician metabasites from the Spanish Central System provides slightly to moderately depleted values and highlights the existence of significant differences between the Tenzuela and Revenga-El Caloco areas. Metagabbros from this latter area show a subtle decoupling between εHf and εNd (εHf above the mantle array) as well as older Hf and Nd model ages. This likely implies that pelagic sediments were recycled in the mantle source of Revenga-El Caloco metabasites during the Cadomian cycle. The isotopic similitude with respect to Variscan basic rocks indicates that juvenile components were not added to the mantle below the Spanish Central System, which did not experience significant modifications from the Ordovician to the end of the Variscan orogeny.
The zircon Lu-Hf isotopic composition of the Ordovician metabasites from the Spanish Central System provides slightly to moderately depleted values and highlights the existence of significant differences between the Tenzuela and Revenga-El Caloco areas. Metagabbros from this latter area show a subtle decoupling between εHf and εNd (εHf above the mantle array) as well as older Hf and Nd model ages. This likely implies that pelagic sediments were recycled in the mantle source of Revenga-El Caloco metabasites during the Cadomian cycle. The isotopic similitude with respect to Variscan basic rocks indicates that juvenile components were not added to the mantle below the Spanish Central System, which did not experience significant modifications from the Ordovician to the end of the Variscan orogeny.