Mantle Expansion Driving Lithosphere Tectonics: The Mediterranean Case

Giusy Lavecchia (a) & Francesco Stoppa (a)
(a) DiS.P.U.Ter, Università "G. d'Annunzio", Campus Universitario, 66013 Chieti Scalo, Chieti, Italy. E-mail: glavecchia@unich.it

We propose a geodynamic model for the Mediterranean area that requires mantle expansion growing eastward, above a relatively cold, chemical plume trapped in the Transition Zone (410-670 km) after that core/mantle perturbations released H, C, N, K, S long trapped within the D” layer. Lithosphere above the expanded asthenosphere underwent stretching and thinning and subordinate peripheral compression. Low-degree melting of the metasomatised asthenosphere produced ultra-alkaline magmas with a distinctive radiogenicity derived by the long term Rb/87Sr and U/Th decay leading to a unique isotopic end-member (ITEM, i.e. Italian Enriched Mantle).

Apennines, geochemistry, geodynamics, ITEM, Mediterranean, mantle expansion, plume