Determination of Volcanic Ash Layers Source of Easter Caucasus Neogene Basin: Evidence from Zircon U-Pb Geochronology and Geochemistry

Okrostsvaridze, Avtandil და Lee, Yuan-Hs და Keskin, Mehmet და Tormey, Daniel და Boichenko, Giorgi და Gogoladze, Salome და Gabrielashvili, Rabi და Makadze, MIriani (2023) Determination of Volcanic Ash Layers Source of Easter Caucasus Neogene Basin: Evidence from Zircon U-Pb Geochronology and Geochemistry. In: Mediterranean Geosciences Union Annual Meeting 2023 (MedGU23).

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რეზიუმე

This article presents new zircon U-Pb geochronology and whole rock geochemistry of the volcanic ash layers of the intermountain Neogene basin of the Eastern Caucasus. Our investigation in the region demonstrates that these ash layers, whose eruption source(s) have not been identified previously, have age and geochemical characteristics of the Kura (Mtkvari) ignimbrite flow of the Samtskhe-Javakheti volcanic highland. The current study shows that zircons from both formations crystallized at the same time ~7.50 Ma ago and have complete geochemical and morphological similarity. Taken together with the geography of the region (200-300 km from the volcanic source to the sedimentation areas), it is likely that the source of the ash layers was the Upper Mio-cene volcanic eruptions on the Samtskhe-Javakheti volcanic highlands. Based on volcanic ash layers distribution, thickness, and age and the analysis of the structure and scale of the Kura ignimbrite flow, the widely-distributed ash likely resulted from a large collapse caldera-forming eruption, in the Samtskhe-Javakheti volcanic highland. These eruptions led to the formation of the large-scale caldera structure (Niala caldera) and the Kura ignimbrite flow. The youngest andesitic flow of this caldera structure has been dated as ~6.5 Ma and appears to mark the termination of the activity associated with the caldera. The supposed caldera extends to the northeastern territory of Türkiye (Turkey), i.e., NE of the Kars Plateau. Ideally, this western portion of the caldera and volcanic highlands can be characterized in the future and a unified structure model of this volcanic center can be established.

ობიექტის ტიპი:	სემინარის ან კონფერენციის მოხსენება (სტატია)
თემატიკა:	Q Science > QE Geology
განმათავსებელი მომხმარებელი:	ავთანდილ ოქროსცვარიძე
განთავსების თარიღი:	08 დეკემბერი 2023 07:11
ბოლო ცვლილება:	08 დეკემბერი 2023 07:11
URI:	http://eprints.iliauni.edu.ge/id/eprint/12344

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