Summary
A wide range of relatively undifferentiated lavas, ranging in composition from quartz-tholeiites to ankaratrites, were erupted in the Iblean area (SE Sicily) during the Upper Miocene-Lower Pleistocene. New Sr-Nd-Pb isotope analyses, presented in this paper, have been used to constrain the petrogenesis of the Iblean magmas, and to characterise their sources. The results (87Sr/86Sr: 0.70271–0.70328;143Nd/144Nd: 0.51325–0.51291;206pb/204Pb: 19.25–20.00) indicate that the Iblean lavas are mantle-derived anorogenic melts, involving DM+HIMU mantle components. Isotope and trace element data suggest that magmas formed from a heterogeneous mantle source that equilibrated in the spinel-peridotite field; the Iblean melts were thus formed within the subcontinental lithosphere. The mantle source region, was originally characterised by a depleted isotopic signature (DM), and was repeatedly and variably impregnated (refertilized) by metasomatic agents of sublithospheric origin characterised by a HIMU signature.
Zusammenfassung
Eine Vielfalt von relativ undifferenzierten Laven, die in ihrer Zusammensetzung von Quarz-Tholeiiten bis zu Ankaratriten reichen, wurden in dem Iblei-Gebiet (Südost-Sizilen) während des Oberen Miozäns — Unteren Pleistoziins eruptiert. Neue Sr-Nd-Pb Isotopenanalysen, die hier präsentiert werden, ermöglichen es, die Möglichkeiten petrogenetischer Deutung der Iblei-Magmen einzuschränken und ihre Quellen zu charakterisieren. Die Resultate (87Sr/86Sr: 0.70271–0.70328;143Nd/144Nd: 0.51325–0.51291;206Pb/204Pb: 19.25–20.00) zeigen, dass die Iblei-Laven anorogene Schmelzen aus dem Mantel sind, die DM+HIMU Komponenten umfassen. Die Isotopen- und Spurenelement-Daten zeigen, dass die Magmen aus einer heterogenen Mantelquelle stammen, die im Spinell-Peridotit-Feld equilibrierte. Die Iblei Magmen haben sich daher innerhalb der subkontinentalen Lithosphäre gebildet. Ihre Ursprungsregion im Mantel war durch eine abgereicherte Isotopensignatur (DM) charakterisiert und wurde wiederholt und in verschiedener Weise durch metasomatische Einflüsse sublithosphärischen Ursprunges imprägniert, die durch eine HIMU Signatur charakterisiert waren.
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Bianchini, G., Bell, K. & Vaccaro, C. Mantle sources of the Cenozoic Iblean volcanism (SE Sicily, Italy): Sr-Nd-Pb isotopic constraints. Mineralogy and Petrology 67, 213–221 (1999). https://doi.org/10.1007/BF01161522
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DOI: https://doi.org/10.1007/BF01161522