Abstract: Lias is represented by the extensive tectonic regime and associated bimodal (basaltic/daeltic) volcanism in the Eastern Pontides, The arc, which has a broad magmatic zone, had been broken upby multiriftlng from the south to the north İn approximataly E*W direction, Pull apart basinsformed by conjugate strike sMp faults in NE-SW and NW-SE directions, have ensmiatic basement to thenorth (inter-arc basins)*During Dogger-Malm interval, tectonic and magmatic activity were very quiet and so carbonate platforms was developed in the back-arc and inter-arc regions,In the Lower Cretaceous, simetric subsidence basins, south and north to the Gümüşhane, were characterized by the turbiditic and olistostromal faciès. This phase corresponds to ending of extensive tec»tonic regime and related passive mantle uprising, and as a result of this rapid subsidence due to cooling ofthe basement*Lower Cretaceous ophiolitic oHstostromal melange, situated southern part of Pontide, is considered toform in a such tectonic regime.Pétrographie and petrochemical studies have been carried out of Liassic volcanic rocks collectedsystematically acros the arc in the N=S direction. In addition to major element analyses, concentrationsof the incompatible element such as K, Rb, Sr, Zr, Y imply that there is variation from transitional tholeitic calc-aikali volcanics in the north (Sürmene) through high K câlc-alkaH rocks of Hamsiköy andTorul area to the high K calc-alkali/alkali basalts in the south (Gümüşhane). We accepted magma mMng hypothesis for the origin Mgh Al and alkali arc lavas in the Gümüşhane/Hamsiköy area,, and defined two distinct magma types, toe trend is characterized by FeO/M^)-enwchment with a slight increase in SiO2 content nrichment with relatively constant FeO/MgO ratios (Si-type trend). Low TiO2 arc basalts to the north and high TiO2 MORB and WPB to the south may have been derived from similar portions of mantle under hydrous conditions provided by descending litospheric slab (arc lavas) and unhydrous condition (MÖRB/WPB) with different partial melting. High TiÖ2 back-arc basin basalt manifested to the south Bayburt, Kelkit, Amasya area correspond to opMolitic basalt formed during Liassic rifting episode.