A series of Cretaceous plutons is present in the eastern Pontides of northeastern Turkey.The Turnagl intrusion is the least studied and,thus,the least understood plutons in the orogen.This intrusion consists of hornblende-biotite granodiorites emplaced at 78 Ma based on LA-ICP-MS U-Pb zircon dating.It is of sub- alkaline affinity,belongs to the medium- to high-K calc-alkaline series,and displays features typical of Itype granites.The rocks of the intrusion are enriched in large-ion lithophile elements and light rare earthelements with negative Eu anomalies(Eu/Eu~*= 0.69-0.82),but are deficient in high-field-strength elements.They have a small range of (~(87)Sr/~(86)Sr)_i(0.7060-0.7063),ε_(Nd_i)(-2.6 to -3.1),and δ~(18)O(+8.1 to +9.1) values.Their Pb isotopic ratios are ~(206)Pb/~(204)Pb = 18.63-18.65,~(207)Pb/~(204)Pb = 15.62-15.63,and ~(208)Pb/~(204)Pb = 38.53-38.55.The fractionation of plagioclase,hornblende,and Fe-Ti oxides had key functions in the evolution of the Tumagl intrusion.The crystallization temperatures of the melts ranged from 758 to 885℃ as determined by zircon and apatite saturation thermometry.All these characteristics,combined with the low values of K_2O/Na_2O and(Na_2O + K_2O)/(FeO~t+MgO + TiO_2),as well as the high values of (CaO + FeO~t + MgO + TiO_2).suggest an origin by dehydration melting from a metabasaltic lowercrustal source. A series of Cretaceous plutons is present in the eastern Pontides of northeastern Turkey. The Turnagl intrusion is the least studied and, thus, the least appreciated plutons in the orogen. This intrusion consists of hornblende-biotite granodiorites emplaced at 78 Ma based on LA-ICP-MS U-Pb zircon dating. Titanium of the sub-alkaline affinity, belongs to the medium- to high-K calc-alkaline series, and displays features typical of Itype granites. The rocks of the intrusion are enriched in large -ion ​​lithophile elements and light rare earthelements with negative Eu anomalies (Eu / Eu ~ * = 0.69-0.82), but are deficient in high-field-strength elements. They have a small range of (~ 87) Sr / ~ 86) Sr) _i (0.7060-0.7063), ε_ (Nd_i) (-2.6 to -3.1), and δ ~ (18) O (+8.1 to +9.1) (204) Pb = 18.63-18.65, 207 Pb / 204 Pb = 15.62-15.63, 208 Pb / 204 Pb = 38.53-38.55. The fractionation of plagioclase, hornblende, and Fe-Ti oxides had key functions in the evolution of the Tumagl in trusion. The crystallization temperatures of the melts ranged from 758 to 885 ° C as determined by zircon and apatite saturation thermometry. All these characteristics, combined with the low values ​​of K_2O / Na_2O and (Na_2O + K_2O) / (FeO_t + MgO + TiO_2), as well as the high values ​​of (CaO + FeO ~ t + MgO + TiO_2) .suggest an origin by dehydration melting from a metabasaltic lowercrustal source.