Geochronology, geochemistry and petrology of the oligocene magmatism in SE segment of the UDMB, Iran

Moghadam H. S., Griffin W. L., Santos J. F., Chen R., KARSLI O., Lucci F., ...Daha Fazla

LITHOS, cilt.416, 2022 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 416
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.lithos.2022.106644
  • Dergi Adı: LITHOS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), Chemical Abstracts Core, Geobase, INSPEC, Pollution Abstracts
  • Anahtar Kelimeler: Arc magmatism, Oligocene, Zircon U-Pb ages, Urumieh-Dokhtar Magmatic Belt, Iran, U-PB GEOCHRONOLOGY, CRUSTAL THICKNESS, SUBDUCTION ZONE, ISOTOPIC CONSTRAINTS, TECTONIC EVOLUTION, FORELAND BASIN, NW ZAGROS, ARC, ZIRCON, MANTLE
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

Despite diverse geochronological-geochemical studies on Cenozoic igneous rocks from the SE segment of the Urumieh-Dokhtar Magmatic Belt (UDMB) of Iran, the nature of the Oligocene magmatic rocks from the farthermost end of the SE segment- where it is linked to the Makran magmatic belt- has been ignored due to the difficulty of access. In this study, we focus on syn-collisional mafic to felsic igneous rocks of calc-alkaline and high-K calc-alkaline affinities from the SE segment of the Urumieh-Dokhtar Magmatic Belt (UDMB) near Nagisun, south of Bam. The Nagisun rocks have low Sr/Y and La-(n)/Yb-(n), similar to igneous rocks from typical arcs. Zircon U-Pb ages show comparable ages for plutonic (similar to 34-25 Ma) and volcanic (similar to 34-27 Ma) rocks. The epsilon Hf(t) values for zircons from plutonic rocks range from 0.3 to +12.8, whereas the epsilon Hf(t) values for the volcanic rocks vary from 2.6 to +13. Modelling of trace elements compositions using Nagisan basaltic samples indicate that an 87:2:11 mixture of the depleted MORB mantle, subducting (trench)-sediments and altered oceanic crust with 5% aggregated fractional melting closely matches the trace-element abundances of the Nagisun basaltic rocks. Indeed, the modelling of Sr and Nd isotopic data emphasizes that the Nagisun magmatic rocks could be products of bulk mixing between a depleted MORB mantle and/or a mixed, fertilized mantle with the Cadomian lower and upper continental crust. Furthermore, our compiled data display that the magmatism in the SE segment of the UDMB changed through time from normal calc-alkaline magmatism to adakitic magmatism at similar to 20 Ma, after the collision with Arabia began ca 27 Ma.