A New Magma Type in the Continental Collision Zone. The Case of Capraia Island (Tuscany, Italy)

The Tuscany Magmatic Province consists of a Miocene to Pleistocene association wide variety rock types, including peraluminous crustal anatectic granites and rhyolites, calcalkaline shoshonitic suites ultrapotassic lamproites. In addition the magma types already recognised, occurrence new, distinct type at Capraia Elba islands in mafic enclaves San Vincenzo rhyolites has been suggested by recent studies. This particular magma, represented intermediate acidic rocks showing high Sr, Ba, LREE, is restricted northwestern sector province time interval about 8 4.5 Ma. New data obtained on from Island have allowed for verification this new type, exploration its origin discussion possible geodynamic significance. high-Sr-Ba andesite-dacite occurring Laghetto area display composition that between adakitic rocks. It they represent originated mantle pressure melting lower continental crust, followed mixing with other magmas. model best explains studied thickening crust during collision, extension favoured crust.