The Eastern Pontides orogenic belt(EPOB)represents a significant segment of the AlpineHimalayan orogenic belt that evolved from the Paleozoic to Cenozoic periods.Here we report new zircon U-Pb ages,together with Lu-Hf...The Eastern Pontides orogenic belt(EPOB)represents a significant segment of the AlpineHimalayan orogenic belt that evolved from the Paleozoic to Cenozoic periods.Here we report new zircon U-Pb ages,together with Lu-Hf isotopes,and whole-rock geochemical and Sr-Nd isotopic analyses of plutonic rocks from EPOB,northeastern Turkey.Our aim is to interpret magmatic evolution in which the granitoids formed.Zircon U-Pb dating of six samples yielded crystallization ages of~134,~82,~39 Ma,respectively.They show a wide range of87Sr/86Sr((i))(0.7039–0.7109),andεNd(t)values varying from-9 to+4.6,yielding model ages(TDM)from 520 to 1623 Ma,suggesting a heterogeneous magma source.Dated zircons show exlusively positiveεHf(t)values(+12.4 to+1.4),yielding model ages(TDM)from 352 to 1059 Ma,implying that they are most likely derived from a juvenile lower crust rather than the mature continental crust.In this study,we suggested that the northward subduction of the Neo-Tethyan oceanic slab began from the Early Cretaceous and resulted in the Late Cretaceous magmatism.Moreover,the Middle Eocene magmatism in the EPOB was related to the collision of the Anatolide Taurid Platform(ATP)with the Pontides.展开更多
基金supported by the Scientific and Technical Research Council of Turkey International Research Fellowship Programme(Nos.TüB?TAK 2214-A,1059B141800146)supported by OYP research foundation。
文摘The Eastern Pontides orogenic belt(EPOB)represents a significant segment of the AlpineHimalayan orogenic belt that evolved from the Paleozoic to Cenozoic periods.Here we report new zircon U-Pb ages,together with Lu-Hf isotopes,and whole-rock geochemical and Sr-Nd isotopic analyses of plutonic rocks from EPOB,northeastern Turkey.Our aim is to interpret magmatic evolution in which the granitoids formed.Zircon U-Pb dating of six samples yielded crystallization ages of~134,~82,~39 Ma,respectively.They show a wide range of87Sr/86Sr((i))(0.7039–0.7109),andεNd(t)values varying from-9 to+4.6,yielding model ages(TDM)from 520 to 1623 Ma,suggesting a heterogeneous magma source.Dated zircons show exlusively positiveεHf(t)values(+12.4 to+1.4),yielding model ages(TDM)from 352 to 1059 Ma,implying that they are most likely derived from a juvenile lower crust rather than the mature continental crust.In this study,we suggested that the northward subduction of the Neo-Tethyan oceanic slab began from the Early Cretaceous and resulted in the Late Cretaceous magmatism.Moreover,the Middle Eocene magmatism in the EPOB was related to the collision of the Anatolide Taurid Platform(ATP)with the Pontides.
