پترولوژی (Dec 2016)
Zircon Hf isotope of Iranian porphyry copper deposits: Constraints on the source of porphyry Cu magma
Abstract
In this research, zircon Hf isotopic ratios from Sungun, Sar Cheshmeh, Meiduk, Darreh Zar and Bondar Hoza porphyry mineralized intrusions has been studied. The Hf isotopic ratios in the studied porphyry intrusions are similar and the average of zircon eHf values from Sar Cheshmeh, Meiduk, Darreh Zar, Bondar Hanza and Sungun porphyry intrusions are +8.2, +9.3, +9.2, +10 and +8.6, respectively. Also, the averages of zircon TDMC ages from the Sar Cheshmeh, Sungun, Meiduk, Darreh Zar and Bondar Hanza porphyry intrusions are 573, 550, 502, 510 and 464, respectively. The positive and restricted eHf values in the studied porphyry intrusion zircons along with the lack of inherited zircons shows continental crust did not contribute in the evolution of the porphyry magmas. The eHf in the studied zircons is between depleted mantle and lower crust values with a tendency towards the depleted mantle. According to adakitic nature of studied porphyry intrusions, post collisional tectonomagmatic setting and their zircon eHf values, the primary magma has been likely originated from a juvenile metamorphosed mafic lower crust with an impressive contribution of depleted mantle.
