Multiple Porphyry Cu-Mo Events in the Eastern Pontides Metallogenic Belt, Turkey: From Early Cretaceous Subduction to Eocene Postcollision Evolution

Four porphyry Cu-Mo systems were investigated by Re-Os molybdenite geochronology to constrain their tinting with respect to the geodynamic and magmatic evolution of the eastern Pontides, Turkey. Molybdenite from the Ispir-Ulutas deposit yielded an Re-Os age of 131.0 +/- 0.7 Ma, which is consistent with Early Cretaceous U-Pb laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon ages of local calcalkaline intrusions. It demonstrates that porphyry deposits were already formed during Early Cretaceous subduction of the Neotethys along the eastern Pontides, and that they can be correlated with porphyry Cu events in the adjacent Lesser Caucasus. Molybdenite Re-Os ages of 76.0 +/- 0.4 and 75.7 +/- 0.4 Ma at the Elbeyli prospect and 77.2 +/- 1.0 Ma at the Emeksen prospect overlap with U-Pb LA-ICP-MS zircon ages of shoshonitic to high-K calc-alkaline intrusions in the region, which were emplaced during Late Cretaceous Neotethys subduction. A 50.7 +/- 0.3 Ma molybdenite Re-Os age at the Guzelyayla deposit confirms porphyry Cu-Mo emplacement coeval with Eocene postcollisional, talc-alkaline adakitic magmatism of the eastern Pontides.