The Central-Western Mediterranean: Anomalous igneous activity in an anomalous collisional tectonic setting

摘要: Abstract The central-western Mediterranean area is a key region for understanding the complex interaction between igneous activity and tectonics. In this review, specific geochemical character of several ‘subduction-related’ Cenozoic provinces are described with view to identifying processes responsible modifications their sources. Different petrogenetic models reviewed in light competing geological geodynamic scenarios proposed literature. Plutonic rocks occur almost exclusively Eocene–Oligocene Periadriatic Province Alps while relatively minor plutonic bodies (mostly Miocene age) crop out N Morocco, S Spain Algeria. Igneous otherwise confined lava flows dykes accompanied by greater volumes pyroclastic (often ignimbritic) products. Overall, spanned wide temporal range, from middle Eocene (such as Province) present (as Neapolitan southern Italy). magmatic products mostly SiO2-oversaturated, showing calcalkaline high-K calcalcaline affinity, except some areas peninsular Italy) where potassic ultrapotassic compositions prevail. magmas (which include leucitites leucite-phonolites) dominantly SiO2-undersaturated, although rare, SiO2-saturated (i.e., leucite-free lamproites) appear over much region, examples being Betics (southeast Spain), northwest Alps, northeast Corsica (France), Tuscany (northwest Italy), southeast Tyrrhenian Sea (Cornacya Seamount) possibly Tell (northeast Algeria). Excepted Alpine case, subduction-related strictly linked formation Sea. This Sea, at least its central western sectors, made up young ( Compared classic collisional settings (e.g., Himalayas), shows range unusual magmatological features. These include: a) rapid extensional basins an overall compressional setting related Africa-Europe convergence; b) centrifugal wave both compressive tectonics starting ‘pivotal’ around Gulf Lyon; c) development concomitant subduction zones different tectonic transport directions; d) ‘inversion’ events currently along Maghrebian coast northern Sicily, previously paleo-European margin); e) repeated pattern whereby gives way intraplate type; f) late-stage appearance collision-related ‘exotic’ (potassic ultrapotassic) compositions, generally absent simple settings; g) relative scarcity typical Italian peninsula; h) absence it might well be expected above hanging-wall Late Cretaceous–Eocene Adria–Europe system Alps); i) voluminous production coeval regimes during Oligo-Miocene Sardinian Trough formation). To summarize, these salient features, characterizing ‘Wilson Cycle’ offer ‘template’ interpreting analogous elsewhere.