Volcanostratigraphy, petrology and magmatic evolution of the Tendurek volcano, Eastern Turkey

Tendürek volcano, located between the cities of Van and Ağrı, is one of the most important eruption centers of collision-related volcanism in Eastern Anatolia during the Quaternary time. It is a two-peaked shield volcano called Greater and Lesser Tendürek respectively, each containing craters at their tops. Tendürek volcano covers a basal area of approximately 600 km2. Our field and laboratory studies on the Tendürek volcano and surroundings have revealed that there are nine compositionally different lava types in and around that volcano: basalt, trachybasalt, basaltic-trachyandesite, trachyandesite, trachyte, phonolite, phonotephrite, tephrite, and tephriphonolite. Our preliminary K/Ar age determinations (conducted at RAS-IGEM; in the frame work of an international joint project coordinated by Prof. Keskin and numbered TÜBİTAK-RFBR 108Y222) imply that the half a million year volcanic activity of Tendürek volcano might have occurred in five discrete stages divided by four pause periods. The K-Ar dating results show that the magmatic activity of the Tendürek Volcano occurred during the Late Pleistocene, over the period of the last 250 thousand years (ka). Five discrete phases of the youngest magmatism were identified in this study: I-710-400 ka, II- 300-190 ka, III- 180-105 ka, IV 100-50 ka and V- ≤ 50 ka. The first two phases were represented by the fissure eruptions of alkaline basic lavas and subsequent formation of vast lava plateaus, the Caldiran and Doğubeyazıt plains. In the following phases, the intermediate and moderately-acid volcanic rocks of midly-alkaline or alkaline series started to dominate among the eruption products. The available geological, isotope-geochronological, and geomorphological data suggest that the Tendürek Volcano is potentially active.