Abstract: The Eastern Pontian arc developed on the sialic basement represents magmatic provences variable in time and spaceduring the Mesozoic and Cenozoic epochs.In the Eastern Black Sea coast tholeiitic volcanism which began in the Lias, turns in tholeiitic/calc-alkaline volcanism in the UpperCretaceous; calc-alkaline volcanism in the Eocene, and alkaline volcanism in the Neogene to make complete successive island arc magmaseries in time.On the other hand, in the contemporaneous volcanic rocks, increasing of K content toward south, cause spatial changes in the arcmagmatism. The Malm-Lower Cretaceous rapid subsidence events in the inter arc/back-arc rift basins which are formed in the Lias, are characterizedby passing from the platform carbonate facies to the olistostromal turbiditic deep marine facies.In the back-arc basins to the south, Bayburt, Kelkit, Amasya regions, this epoch mentioned above, corresponds to the time of theformation of the ophiolitic olistostromal melange.Basaltic rocks, which constitute ophiolitic melange have within plate and mid ocean ridge/island arc affinities (poligenetic ophioliteconcept).This melange is in turn overlain by the high K calc-alkaline andesite with pyroclast and the Upper Cretaceous rudist-bearing limestonesin the Bayburt, Maden area.In the Everek Hanları district these Upper Cretaceous limestones are accompained with a formation with couldn`t be exactly definedgeologically by now and were mapped as ophiolitic series with tectonic contact, and so this caused contradictory interpretations. Duringour field study we observed that the formation mentioned above is rested unconformably on the erosional surface of the Upper Cretaceouslimestones and comprise the low TİO2 leucite-bearing alkaline basalts intercalated with the continental red colour cross bedding detritusand is overlain by the Paleogene turbidites with the basement conglomerates.This formation defined geologically was called Everek Hanları Formation.The calc-alkaline and low TiO2 alkaline volcanism (shoshonitic) which cover the ophiolitic melange with sedimentary origin are strongevidence to imply that this melange formed in the back-arc geotectonic environment. We have similar geologic observation in Amasya.Manifestation of this leucite-bearing volcanism which of approximately 60 m.y. of age, in the northern part of the Eastern Pontian arcalong the Black Sea coast in the Neogene, imply that the high K volcanism regressed together with the arc magmatism toward thetrench during the Cenozoic time just as known in the Nortwestern America.On the other hand, contemporaneous magmatism and subsidence events are suggestive that mantle uprising had the main role inthese concept in the Eastern Pontian arc/back-arc geotectonic environments.