Providing a detailed glass geochemistry for key tephra layers of Lake Van, Eastern Anatolian Volcanic Province

The volcanoes of Nemrut and Süphan in the Eastern Anatolian Volcanic Province (EAVP) have been active throughout the late Quaternary, dispersing ash over wide areas. Numerous eruptions spanning the last interglacial to glacial period (130-30kya) are recorded in outcrops around the volcanoes and in the cores from Lake Van. A comprehensive tephrostratigraphy framework for the EAVP is an essential requirement for synchronising palaeoclimatic and archaeological records across the Mediterranean region. More information is required from the eruption deposits, including glass geochemistry on individual shards, and the stratigraphic order and precise ages for the eruptions.

Here we present the findings of our detailed tephra investigation for the palaeoclimatic record of Lake Van (Turkey), as part of the TephroMed project. The lake is located close to both Nemrut and Süphan. Fourteen visible tephra layers (called V-layers) from Lake Van PALEOVAN ICDP record underwent geochemical characterisation by using major, minor (EPMA) and trace element analysis (LA-ICP-MS). New chemical analyses and ⁴⁰Ar/³⁹Ar ages of eruption deposits from proximal outcrops, provide detailed insight into the complex volcanic history of the EAVP, particularly of Nemrut. These results have revealed new volcanic origins for certain V-layers to Nemrut and Süphan, with tentative correlations between Lake Van’s fourteen V-layers to previously published dated proximal outcrops. Additionally, new glass geochemistry from dated proximal outcrops confirm the ages of the key eruption events associated with V-51 and V-18a of Lake Van. This improves the chronology of the Lake Van record and provides an understanding for the timing of complex eruptions from Nemrut and Süphan. The results are a major step forward to building a detailed tephrostratigraphic framework for the EAVP.