TY - JOUR A1 - Omrani, Hadi A1 - Moazzen, Mohssen A1 - Oberhänsli, Roland A1 - Altenberger, Uwe A1 - Lange, Manuela T1 - The Sabzevar blueschists of the North-Central Iranian micro-continent as remnants of the Neotethys-related oceanic crust subduction JF - International journal of earth sciences N2 - The Sabzevar ophiolites mark the Neotethys suture in east-north-central Iran. The Sabzevar metamorphic rocks, as part of the Cretaceous Sabzevar ophiolitic complex, consist of blueschist, amphibolite and greenschist. The Sabzevar blueschists contain sodic amphibole, epidote, phengite, calcite +/- A omphacite +/- A quartz. The epidote amphibolite is composed of sodic-calcic amphibole, epidote, albite, phengite, quartz +/- A omphacite, ilmenite and titanite. The greenschist contains chlorite, plagioclase and pyrite, as main minerals. Thermobarometry of a blueschist yields a pressure of 13-15.5 kbar at temperatures of 420-500 A degrees C. Peak metamorphic temperature/depth ratios were low (similar to 12 A degrees C/km), consistent with metamorphism in a subduction zone. The presence of epidote in the blueschist shows that the rocks were metamorphosed entirely within the epidote stability field. Amphibole schist samples experienced pressures of 5-7 kbar and temperatures between 450 and 550 A degrees C. The presence of chlorite, actinolite, biotite and titanite indicate greenschist facies metamorphism. Chlorite, albite and biotite replacing garnet or glaucophane suggests temperatures of > 300 A degrees C for greenschist facies. The formation of high-pressure metamorphic rocks is related to north-east-dipping subduction of the Neotethys oceanic crust and subsequent closure during lower Eocene between the Central Iranian Micro-continent and Eurasia (North Iran). KW - Central Iranian micro-continent (CIM) KW - Neotethys Ocean KW - Glaucophane schist KW - Sabzevar KW - Iran Y1 - 2013 U6 - https://doi.org/10.1007/s00531-013-0881-9 SN - 1437-3254 VL - 102 IS - 5 SP - 1491 EP - 1512 PB - Springer CY - New York ER -