Major volcano-sedimentary facies types of the Madneuli polymetallic deposit, Bolnisi district, Georgia: implications for the host rock depositional environment

The Madneuli polymetallic deposit is the major deposit of the Bolnisi ore district in the southeastern part of Georgia, which is in production since the 70's. The Bolnisi district is part of the Lesser Caucasus; it extends towards the west in the Eastern Pontides, Turkey. The origin of the Madneuli deposit is still controversial. Our study is based on physical volcanology and sedimentary basin analyses. Eleven principal volcanic and volcano-sedimentary facies types were identified within the Madneuli open pit based on their composition, texture, volcanic and sedimentary structures. The presence of various submarine sedimentary structures, hyaloclastite and turbiditic rocks and Radiolaria described for the first time within the host rocks of the Madneuli open pit, supports the submarine depositional setting for the volcano-sedimentary succession hosting the Madneuli deposit.