Eruptive recurrence and magma accumulation for Quaternary stratovolcanoes in Central Anatolia

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Erciyes Dagi and Hasan Dagi are the two largest stratovolcanoes in Central Anatolia. Both volcanoes are considered active, with more than 1 Million people residing in close proximity to Erciyes Dagi alone. This assessment is largely based on Turkey's uniquely protracted archaeological record of human presence which yielded tentative evidence for coeval volcanic eruptions of Erciyes Dagi and Hasan Dagi from prehistoric to historic times. Eruption ages of both volcanoes, however, are poorly quantified, and their impacts on past cultural evolution and potential threats for modern society therefore remain tenuous. This proposal is to study the timing and underlying magmatic processes of late Pleistocene to Holocene volcanism of Erciyes Dagi and Hasan Dagi. For the most recent deposits of both volcanoes, combined uranium series disequilibrium and (U-Th)/He dating will be applied to the accessory mineral zircon to accurately constrain eruptive recurrence. To better understand the long-term evolution of the magmatic systems underpinning both volcanoes, uranium series zircon crystallization ages, as well as the chemical and isotopic composition of zircon will be used. Zircon is uniquely inert against diffusion of geochronologically and geochemically important trace elements so that it can record the timing of the thermal and compositional evolution of magmas at absolute and protracted timescales. This transcends conventional analysis of volcanic rocks, which can only yield an instantaneous view into the physical and chemical state of magma immediately before eruption. Because of the temperature dependence of zircon crystallization in magmas, zircon is ideally suited to quantify rates of magma accumulation and cooling. The comparative investigation of two neighboring volcanoes allows testing of models regarding the importance of exogenic processes such as glaciation-deglaciation cycling on the frequency of volcanic eruptions. Collectively, these data are critical for the re-evaluation of Quaternary tephra records in the Eastern Mediterranean and Black Sea regions, with implications for dating of climate and archaeological archives and the assessments of volcanic hazards in this region. Broader impacts of this proposal are to further develop collaborative research on volcanoes in Central Anatolia with Turkish scientists, to promote international exchange of students and researchers, and to raise public awareness for volcanic hazards in an important region at the crossroads between Europe and Asia.