Geochronology of subduction-related metamorphic rocks from the Central Indonesian Accretionary Collision Complex

本提案为实地研究活动寻求资金，旨在为深入了解印度尼西亚中部吸积碰撞复合体（CIACC）中与俯冲和碰撞有关的变质过程建立坚实的地质年代学基础。前人的研究概述了该地区变质岩的基本领域、岩石学和地球化学背景。然而，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在定量和定性方面都不够，无法对地质历史进行有意义的解释。这些数据对于正确解释地质历史是至关重要的，并且有可能大大促进对CIACC记录的俯冲-挖掘事件的理解。在之前的一项研究中，研究人员对来自Bantimala（苏拉威西岛）和Luk Ulo（爪哇）的变质岩进行了新的年龄研究，结果显示，由于早期K-Ar数据集的精度较低，HP/LT阶段的年龄差异在以前没有被认识到。新的地质年代学证据为深入认识中国大陆不同段的不同变质史开辟了新的视角。为了充分了解沿CIACC运行的P-T-D-t过程的演化，并充分解决大地构造背景，需要进行更多的研究。更全面的区域覆盖是提高对地球动力学过程理解的先决条件，这些过程导致了更大研究区域前第三纪增生复合体的形成。为此，有必要用其他产层的年龄和P-T信息来补充现有数据，并通过额外的岩石学和年龄数据来提高对已经研究过的位置的认识。为了建立一个更全面的同位素年龄区域覆盖范围，下一步的逻辑是将重点放在来自CIACC其他部分的变质岩上。在这种情况下，Meratus复合体（南Kali-mantan）在地球动力学方面具有特别重要的意义。新时代数据将有助于在更广泛的区域尺度上解决地球动力学演化的时空格局，并将为印度尼西亚地壳结构的发展提供新的见解。新获得的知识将为印度尼西亚中部地区的古生物学重建、区域相关性和大规模地球动力学过程的改进解释提供坚实而坚实的基础。

This proposal seeks funding for field-based research activities that aim at establishing a solid geochronologic foundation for in-depth understanding of subduction- and collision-related metamorphic processes in the Central Indonesian Accretionary Collision Complex (CIACC). Previous studies have outlined the essential field, petrological and geochemical context of the metamorphic rocks from the CIACC. However, 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 under both quantitative and qualitative aspects for meaningful interpretation of the geologic history. Such data are crucial for a correct interpretation of the geologic histories and have the potential to significantly advance the understanding of the subduction–exhumation events recorded in the CIACC. New age data produced in a previous study focusing on metamorphic rocks from Bantimala (Sulawesi) and Luk Ulo (Java) revealed distinct age differences for the HP/LT stage that had previously not been recognized, due to the poor precision of an earlier K–Ar data set. The new geochronologic evidence has opened up new perspectives for an in-depth understanding of diverse metamorphic histories in different segments of the CIACC. More research is needed to fully understand the P–T–D–t evolution of the processes operating along the CIACC and to fully resolve the geotectonic context. A more comprehensive regional coverage is a prerequisite for an improved understanding of the geodynamic processes that have led to the formation of the pre-Tertiary accretionary complexes of the larger study area. For this purpose it will necessary to complement the existing data with age and P–T information for other occurrences, and to improve the knowledge of already studied locations by additional petrologic and age data. In order to establish a more comprehensive regional coverage with isotopic ages the logical next step is to focus on the metamorphic rocks from other parts of the CIACC. In this context the Meratus complex (south Kali-mantan) is of special importance for geodynamic considerations. New age data will help resolving spatial and temporal patterns in the geodynamic evolution on a broader regional scale, and will provide new insights into the development of the crustal architecture of Indonesia. The newly gained knowledge will provide a solid and robust foundation for refinement of palinspastic reconstructions, regional correlations and an improved interpretation of large-scale geodynamic processes in the central Indonesian region.