Zircon xenocrysts in late cretaceous magmatic rocks in the kermanshah ophiolite: link to Iran continental crust supports the subduction initiation model
INTERNATIONAL GEOLOGY REVIEW, vol.64, no.22, pp.3248-3259, 2022 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 64 Issue: 22
- Publication Date: 2022
- Doi Number: 10.1080/00206814.2022.2043193
- Journal Name: INTERNATIONAL GEOLOGY REVIEW
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC, Pollution Abstracts
- Page Numbers: pp.3248-3259
- Karadeniz Technical University Affiliated: No
Abstract
Geochronological and geochemical data show that Late Cretaceous Zagros ophiolites were generated by forearc seafloor spreading during a subduction initiation event along the southwestern margin of Iran. These ophiolites define a similar to 3000 km long belt passing from Cyprus to Turkey, Syria, Iran, the UAE, and Oman. Ten samples of plagiogranites, amphibole gabbros and diorites of the Kermanshah ophiolite yield U-Pb zircon magmatic ages indicating ophiolite formation at 98 to 96 Ma. Some Kermanshah rocks also contain abundant zircon xenocrysts with age peaks (in order of decreasing size): Triassic (similar to 247 Ma), mid-Paleoproterozoic (similar to 2150 Ma), Late Paleoproterozoic (similar to 1850 Ma), Late Ediacaran (similar to 560 Ma), Early Cretaceous (similar to 140 Ma), and Tonian (similar to 850 Ma). Similar age peaks are seen in magmatic and detrital rocks of Iranian crust to the north. The xenocrysts have epsilon Hf(t) values from +6.3 to - 21.6, corresponding to depleted mantle Hf model ages (T-DM) of 0.6 to 3.6 Ga. The xenocryst age peaks are similar to those of zircons in Iranian continental crust. The occurrence of zircon xenocrysts in the Kermanshah ophiolite suggests that this formed adjacent to the Iranian continent, as expected for Late Cretaceous subduction initiation.