Upwelling of deep mantle material through a plate window: Evidence from the geochemistry of Italian basaltic volcanics

D. Gasperini (1, 2) , J. Blichert-Toft (1) , Delphine Bosch (3) , A. del Moro (4) , P. Macera (2) , Francis Albarède (1)

1 ENS de Lyon - École normale supérieure de Lyon
2 Dipartimento di Scienze della Terra [Pisa]
3 Tectonophysique - Laboratoire de Tectonophysique
4 IGG-CNR - CNR Istituto di Geoscienze e Georisorse [Pisa]

The isotopic compositions of basaltic lavas from the Quaternary and Plio-Pleistocene Italian volcanics (Tuscan Magmatic Province, Roman Magmatic Province, Vesuvius, Aeolian Islands, Etna, and Iblean Basin) define binary hyperbolic relationships in the 87Sr/86Sr–206Pb/204Pb–eNd–eHf space. The isotopic compositions of the two end-members of these mixing arrays are assessed by least-squares regression. The mantle-derived component (206Pb/204Pb = 19.8, 87Sr/86Sr = 0.7025, ∑Nd = +8, ∑Hf = +9) is a rather homogeneous mixture of the standard high-m (HIMU) and depleted mantle (DM) components. The crust-derived component (206Pb/204Pb = 18.5, 87Sr/86Sr > 0.715, ∑Nd = -12, ∑Hf = -11) accounts for the enrichment of K and other large-ion-lithophile elements in the Italian volcanics.

Mots clés: Italian volcanism; HIMU; Subduction; Pelagic sediments; Mixing; Slab window

Domaines: Géochimie

D. Gasperini, J. Blichert-Toft, Delphine Bosch, A. del Moro, P. Macera, et al.. Upwelling of deep mantle material through a plate window: Evidence from the geochemistry of Italian basaltic volcanics. Journal of Geophysical Research : Solid Earth, 2002, 107 (B12), pp.ECV 7-1-ECV 7-19. ⟨10.1029/2001JB000418⟩. ⟨hal-03882971⟩