Unravelling metamorphic ages of suture zone rocks from the Makran and Sabzevar areas (Iran):new constraints for the temporal evolution of the Arabia-Eurasian collision zone

围绕伊朗微大陆块体的缝合带的地质、构造变质和岩浆演化的许多方面尚不清楚，仅在侦察水平上了解。特别是关于区域变质作用的时间和地球动力学意义的认识是零碎的，需要进一步关注。相对于其地理范围而言，同位素年龄数据的区域覆盖范围不足以对地质历史进行有意义的解释。缺乏可靠的地质年代学数据是深入了解地球动力学演化、改善区域相关性和完善受阿拉伯、欧亚和阿富汗板块相互作用强烈影响的总体地质图景的主要障碍。为了提高对控制阿拉伯-欧亚碰撞带地球动力学演化的板块重组的认识，本研究寻求资助在Makran和Sabzevar地区进行实地研究，旨在帮助建立一个地质年代学数据库，该数据库可以作为一个框架，用于更详细地解释沿伊朗中部微大陆外围运行的俯冲-挖掘过程。对构造和变质演化的解读需要坚实的地质年代学基础。以前的研究概述了基本领域和岩石学背景。然而，需要更多的研究来加深我们对这些事件的P-T-D-t演变的理解。为了充分了解伊朗微板块拼合的时空演化，有必要通过将P-T和地质年代学信息联系起来，揭示完整的变质演化过程，不仅包括HP/LT岩石，还包括密切相关的绿片岩和/或角闪岩相岩石。对于HP/LT阶段和强叠印岩石，目前还没有足够的地质年代学数据，但需要破译缝合带的完整构造变质史。准确和精确的年龄是避免对地质历史的理解产生深远影响的误解的先决条件。为了在地球动力学重建中更好地整合Makran和Sabzevar地区的变质岩，对变质作用的时间进行强有力的年龄约束至关重要。通过系统地弥补研究地区仍然不完整的地质年代学调查的空白，可以期待对更广泛的地球动力学背景的理解提供新的视角。主要目标是帮助建立阿拉伯-欧亚汇聚边界地球动力学历史的基本时间框架，并提高我们对沿碰撞带运行的复杂构造变质过程的理解。

Many aspects of the geological, tectono-metamorphic and magmatic evolution of the suture zones surrounding Iranian microcontinental blocks are as yet poorly constrained and only known on a reconnaissance level. Especially the knowledge about the timing and geodynamic significance of regional metamorphic processes is fragmentary and needs further attention. Relative to its geographic extent, the regional coverage with isotopic age data is insufficient for meaningful interpretation of the geologic history. The lack of robust geochronological data is a major obstacle for in-depth understanding of the geodynamic evolution, improved regional correlations and refinement of the general geologic picture that has been strongly affected by the interaction between the Arabian, Eurasian and Afghan plates. In order to improve knowledge of the plate reorganizations controlling the geodynamic evolution of the Arabia-Eurasian collision zone this study seeks funding for field-based research in the Makran and Sabzevar areas, aiming to assist in building up a geochronological database that can serve as a framework for a more detailed geodynamic interpretation of the subduction–exhumation processes operating along the periphery of the Central Iranian Microcontinent. Deciphering of the tectonic and metamorphic evolution requires a solid geochronologic foundation. Previous studies have outlined the essential field and petrological context. Still, more research is needed to deepen our understanding of the P–T–D–t evolution of these occurrences. In order to fully understand the spatial and temporal evolution of the Iranian microplate collage, it will be necessary to unravel the complete metamorphic evolution by linking P–T and geochronological information, not only for the HP/LT rocks, but also for closely associated greenschist- and/or amphibolite facies rocks. Neither for the HP/LT stage nor for strongly overprinted rocks an adequate geochronological dataset is yet available, but is required to decipher the complete tectono-metamorphic histories of the suture zones. Accurate and precise ages are a prerequisite to avoid misinterpretation with far-reaching consequences for the understanding of a geological history. In order to better integrate the metamorphic rocks from the Makran and Sabzevar areas in geodynamic reconstructions, robust age constraints for the timing of metamorphism are of utmost importance. New perspectives for understanding of the broader geodynamic context can be expected by systematically closing the gaps in the still patchy geochronological investigation of the study areas. The main goal is to help establishing the essential temporal framework for the geodynamic history of the Arabia-Eurasian convergent boundary and to improve our understanding of the complex tectonometamorphic processes operating along this collision zone.