Preliminary Investigation of Volcanic Succession and Mineralogy of the Southern part of Mount Ağrı, Eastern Anatolia, Turkey

Preliminary Investigation of Volcanic Succession and Mineralogy of the Southern part of Mount Ağrı, Eastern Anatolia, Turkey

Zeynep Madak1*, Elif Varol1, G. Deniz Doğan-Külahcı1

1  Hacettepe University, Department of Geological Engineering, 06800, Ankara, Türkiye

Mount Ağrı is a significant stratovolcano located in Eastern Anatolia, Turkey, characterized by its steep conical shape and unique ice-capped structure. It is generally considered part of the Alpine-Himalayan orogenic belt and developed in the Quaternary, with its last known eruption occurring in 1840.   The volcanic succession in the southern part of Mount Ağrı begins with basaltic volcanic lava flows. These lower lava flow units exhibit a hypocrystalline porphyritic texture and contain a mineral assemblage of plagioclase + pyroxene ± olivine + oxide. These lava flows are overlain by a series of Plinian pumice-fall deposits of varying thicknesses of layers, which include ash-size volcanic material, different sizes of normally graded pumices, and inversely graded lithic clasts. Predominantly slaty fabric is observed in the pumices, with the thickness of pyroclastic fall deposits ranging up to 20 m and the color of the sequences varying between beige and white.   Finally, younger lava flows overlie these pyroclastic sequences. These younger lavas generally exhibit a hypocrystalline porphyritic texture, although an aphanitic texture has also been observed. The upper lava flow units display a mineral assemblage of pyroxene + plagioclase + oxide. The ongoing geochemical analyses will unveil the processes influencing the formation of these volcanic rocks and help determine the origin of the magma.

Key words: Mount Ağrı, Eastern Anatolia,  plinian fall deposits, lava flow, mineralogy