The Sabzevar blueschists of the North-Central Iranian micro-continent as remnants of the Neotethys-related oceanic crust subduction
The Sabzevar blueschists of the North-Central Iranian micro-continent as remnants of the Neotethys-related oceanic crust subduction
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伊朗中北部微大陆的 Sabzevar 蓝片岩是与新特提斯相关的洋壳俯冲的残余物
DOI：
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发表时间：
2013
影响因子：
2.3
通讯作者：
M. Lange
中科院分区：
文献类型：
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作者：
H. Omrani;M. Moazzen;R. Oberhänsli;U. Altenberger;M. Lange
萨卜泽瓦尔蛇绿岩标志着伊朗东北部的新特提斯缝合线。萨卜泽瓦尔变质岩是白垩纪萨卜泽瓦尔蛇绿杂岩的一部分，由蓝片岩、角闪岩和绿片岩组成。萨卜泽瓦尔蓝片岩含钠质角闪石、绿帘石、多硅白云母、方解石±绿辉石±石英。绿帘角闪岩由钠钙角闪石、绿帘石、钠长石、多硅白云母、石英±绿辉石、钛铁矿和钛铁矿组成。绿片岩的主要矿物为方解石、斜长石和黄铁矿。蓝片岩的热压法在420-500 °C的温度下产生13-15.5千巴的压力。峰值变质温度/深度比较低（~12 °C/km），与俯冲带的变质作用一致。蓝片岩中绿帘石的存在表明岩石完全在绿帘石稳定区内变质。角闪石片岩样品经历了5-7千巴的压力和450 - 550 °C的温度。黄铁矿、阳起石、黑云母和钛铁矿的存在表明绿片岩相变质作用。绿片岩相的温度高于300 °C，绿片岩相中绿绿泥石、钠长石和黑云母取代了石榴石或蓝闪石。高压变质岩的形成与新特提斯洋壳的东北倾俯冲和随后的中伊朗微大陆和欧亚大陆（伊朗北部）之间的下始新世闭合有关。
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 ± omphacite ± quartz. The epidote amphibolite is composed of sodic-calcic amphibole, epidote, albite, phengite, quartz ± 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 °C. Peak metamorphic temperature/depth ratios were low (~12 °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 °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 °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).