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

伊朗微大陆区块周围缝合带的地质、构造变质和岩浆演化的许多方面迄今限制较少，仅在侦察层面上为人所知。特别是对区域变质作用的时间和地球动力学意义的认识还是零碎的，需要进一步关注。相对于其地理范围，同位素年龄数据的区域覆盖面不足以对地质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、改善区域对比和完善受阿拉伯、欧亚和阿富汗板块之间相互作用强烈影响的一般地质图景的主要障碍。为了增进对控制阿拉伯-欧亚碰撞带地球动力学演化的板块重组的了解，本研究寻求为Makran和Sabzevar地区的实地研究提供资金，旨在协助建立一个地球年代学数据库，作为更详细的地球动力学解释沿伊朗中部微大陆外围活动的俯冲-折返过程的框架。破译构造和变质演化需要坚实的地质年代学基础。以前的研究已经概述了基本领域和岩石学背景。尽管如此，还需要更多的研究来加深我们对这些事件的P-T-D-T演化的理解。为了全面了解伊朗微板块拼贴的空间和时间演化，有必要通过将P-T和年代学信息联系起来来揭示完整的变质演化，不仅是HP/LT岩石，而且是密切相关的绿片岩和/或角闪岩相岩石。无论是对于HP/LT阶段，还是对于强烈叠加的岩石，都没有足够的年代学数据集，但需要用来破译缝合带的完整构造变质历史。准确和准确的年龄是避免误解并对地质史的理解产生深远影响的先决条件。为了更好地将Makran和Sabzevar地区的变质岩整合到地球动力学重建中，对变质作用时间的可靠年龄限制是至关重要的。通过系统地弥合研究地区仍然参差不齐的地质年代学调查中的差距，可以预期对更广泛的地球动力学背景的理解有新的视角。主要目的是帮助建立阿拉伯-欧亚会聚边界地球动力学历史的基本时间框架，并提高我们对沿这一碰撞带活动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.