Recent studies on Central and Eastern Anatolia volcanism

A diffuse Neogene-Quaternary volcanic belt crops out in Central and Eastern Anatolia. Since the early ’60s, several Italian geologists, in collaboration with Turkish colleagues investigated many Anatolian sectors characterized by the presence of igneous activity. The main aim was to infer the causes of activation of their mantle sources in terms of local and global-scale geology constraining the timespace distribution of the the volcanic products. Latest studies were first targeted on the Karacadağ shield volcano (the Southeastern Anatolia), the biggest volcanic edifice of the whole circum-Mediterranean area, occupying an area in the order of 104 km2, on the Arabian plate foreland, characterized by alkali basaltic products with OIB-HiMu geochemical signature. Other studies, still in progress, highlight the occurrence of both orogenic and anorogenic products in three areas: Central Anatolia (from Konya to Sivas, including Kapadokya), SE Anatolia (around ßanlıurfa and Gaziantep), and the westernmost sector of Eastern Anatolia (between Elazığ and Bingöl). An almost continuos shift from calc-alkaline igneous activity to mildly sodic alkali basaltic compositions, with some products with transitional affinity, is commonly recorded essentially only in the westernmost areas. On the other hand, in Central and SE Anatolia a clear temporal evolution of the erupted magmas in terms of important changes in major oxides, trace elements as well as Sr-Nd-Pb isotopic ratios is not recorded. Indeed here a largely overlapping (both in terms of space and time) “orogenic” and “anorogenic” products is commonly observed. On the other hand, calc-alkaline lavas clearly predate alkali basalts (with transitional products showing intermediate age) in Eastern Anatolia.