An International Collaborative Investigation of Khoy Ophiolite, NW, Iran

Bitlis-Zagros缝合带的蛇绿岩形成了一条不连续的特提斯海洋碎片线性带，构成了阿曼的Samail蛇绿岩和塞浦路斯的Troodos蛇绿岩之间的桥梁。Bitlis-Zagros缝合带的伊朗蛇绿岩包括Neyriz、Kermanshah和可能在Khoy的复合体。目前，我们对这些蛇绿岩成因的许多基本方面(如地幔来源、岩石成因、构造环境和形成时间、侵位时间和机制)的认识存在巨大差距，从而对中东和东地中海地区的中新生代地质以及特提斯古地理的理解也存在巨大差距。伊朗西北部的Khoy蛇绿岩特别适合研究，因为1)它是该地区最大的完整杂岩之一，具有可测绘的蛇绿岩伪地层，2)它有一个定义明确的变质岩底，其岩石表现出从角闪岩相到绿片岩相的逆温梯度效应，3)它位于沿阿拉伯海角的地中海和中东蛇绿岩带的重要交界处，4)它被特提斯洋闭合重建的构造模型所忽视。这一研究结果将加深对大洋扩张中心岩浆作用、洋壳形成和蛇绿岩成因侵位等物理化学过程的认识。最终，我们希望建立一个现代的、高质量的地球化学数据库，评估这个鲜为人知的地区的古代构造岩浆作用，并回答一些关于特提斯和印度洋岩浆作用、海洋闭合的时间和构造、上地幔内地球化学域的演化以及蛇绿岩一般成因的基本问题。

9903249GhaziThe ophiolites of the Bitlis-Zagros Suture Zone zone form a discontinuous linear belt of Tethyan oceanic fragments which form a bridge between the Samail Ophiolite in Oman and the Troodos ophiolite in Cyprus. The Iranian ophiolites of the Bitlis-Zagros Suture Zone include complexes at Neyriz, Kermanshah and possibly at Khoy. Currently there is an immense gap in our knowledge about many fundamental aspects of genesis of these ophiolites (e.g., the mantle sources, the petrogenetic origin, the tectonic environment and timing of formation, timing and mechanism of emplacement) and thus in our understanding of the Mesozoic-Cenozoic geology of the Middle East and Eastern Mediterranean regions as well as of Tethyan paleogeography. The Khoy ophiolite of northwestern Iran is especially suitable to study because; 1) it is one of the largest intact complexes in the region with a mappable ophiolite pseudostratigraphy, 2) it has a well-defined metamorphic sole whose rocks show effects of an inverse thermal gradient from amphibolite facies to greenschist facies, 3) it is located at an important junction between the belts of Mediterranean and Middle Eastern ophiolites along the Arabian promontory, and 4) it has been overlooked in tectonic models for reconstruction of closure of the Tethys Ocean. The results of this study will advance understanding of the physiochemical processes involved in magmatism at oceanic spreading centers, formation of oceanic crust, and ophiolite genesis and emplacement. Ultimately, we hope to generate a modern, high-quality geochemical database and evaluate ancient tectonomagmatic processes in this little-studied region and answer some of the fundamental questions about Tethyan and Indian Ocean magmatism, timing and tectonics of ocean closure and the evolution of geochemical domains within the upper mantle, and ophiolite genesis in general.