During Tertiary to Quaternary times, convergence between Eurasia and Africa resulted
in a variety of collisional orogens and different styles of subduction in the Alpine-Mediterranean
region. Characteristic features of this area include arcuate orogenic belts and extensional
basins, both of which can be explained by roll-back of subducted slabs and retreating
subduction zones. After cessation of active subduction, slab detachment and post-collisional
gravitational collapse of the overthickened lithosphere took place. This complex tectonic
history was accompanied by the generation of a wide variety of magmas. Most of these
magmas (e.g. low-K tholeiitic, calc-alkaline, shoshonitic and ultrapotassic types)
have trace element and isotopic fingerprints that are commonly interpreted to reflect
enrichment of their source regions by subduction-related fluids. Thus, they can be
considered as 'subduction-related' magmas irrespective of their geodynamic relationships.
Intraplate alkali basalts are also found in the region and generally postdated the
'subduction-related' volcanism. These mantle-derived magmas have not (or only slightly)
been influenced by subduction-related enrichment. This paper summarizes the geodynamic
setting of the Tertiary-Quaternary 'subduction-related' magmatism in the various segments
of the Alpine-Mediterranean region (Betic-Alboran-Rif province, Central Mediterranean,
the Alps, Carpathian-Pannonian region, Dinarides and Hellenides, Aegean and Western
Anatolia), and discusses the main characteristics and compositional variation of the
magmatic rocks. Radiogenic and stable isotope data indicate the importance of continental
crustal material in the genesis of these magmas. Interaction with crustal material
probably occurred both in the upper mantle during subduction ('source contamination')
and in the continental crust during ascent of mantle-derived magmas (either by mixing
with crustal melts or by crustal contamination). The 87Sr/86Sr and 206Pb/204Pb isotope
ratios indicate that an enriched mantle component, akin to the source of intraplate
alkali mafic magmas along the Alpine foreland, played a key role in the petrogenesis
of the 'subduction-related' magmas of the Alpine-Mediterranean region. This enriched
mantle component could be related to mantle plumes or to long-term pollution (deflection
of the central Atlantic plume and recycling of crustal material during subduction)
of the shallow mantle beneath Europe since the late Mesozoic. In the first case, subduction
processes could have had an influence in generating asthenospheric flow by deflecting
nearby mantle plumes as a result of slab roll-back or slab break-off. In the second
case, the variation in the chemical composition of the volcanic rocks in the Mediterranean
region can be explained by 'statistical sampling' of the strongly inhomogeneous mantle
followed by variable degrees of crustal contamination.
