Zircon U–Pb ages, Hf isotopes and geochemistry of the schists, gneisses and granites in Delbar Metamorphic-Igneous Complex, SE of Shahrood (Iran): Implications for Neoproterozoic geodynamic evolutions of Central Iran

• The DMIC complex in Central Iran has originated in an active continental margin.
• U–Pb dating of the DMIC gneisses and granites yielded the 541–547 Ma.
• U–Pb dating yielded the ages of 549–551 Ma for detrital zircons of para-gneiss.
• The evolution of DMIC is related to the Cadomian arc in the Northern Gondwana margin.

The Delbar Metamorphic-Igneous Complex (DMIC) consists of the medium to high-grade metamorphic rocks and granites – leucogranites is located in the Biarjmand region, in Central Iran. U–Pb dating of the gneisses yielded the ages of 546 ± 3.7–547 ± 6.8 Ma similar to the crystallization ages of leucogranites (541 ± 4.7–547 ± 11 Ma) are consistent to the Late Ediacaran–Early Cambrian ages of Cadomian magmatic arc (∼545 Ma). The 206Pb/238U ages of the detrital zircons from the mica-schists sample are from 551 ± 5.1–549 ± 5.1 Ma. The youngest ages of the meta-pelitic protolith have 10 Ma age intervals compared to the granites emplacement age, which indicates rapid Late Precambrian crustal recycling involving erosion, burial, metamorphism to partial melting of the continental crust in less than ca. 10 Ma. These rapid crustal evolutions were related to the final collision and amalgamation of Gondwana, the Rheic Ocean clouser and coeval paleotethys opening at the end of the Avalonian–Cadomian orogeny. The studied granites are similar to the volcanic arc granitoids and originated from the crustal source in an active continental margin based on the geochemical characteristics and Hf isotopes data. Exhumation of the DMIC Complex, is marked by deposition of Lower Jurassic conglomerates contains pebbles of basement rocks. These rocks were interrupted by mafic swarms dikes that have generated in a back arc extensional setting related to the Neotethys subduction under the Central Iran at the 152 ± 35 Ma (Middle–Late Jurassic) based on the U–Pb apatite dating.