The Sistan Suture Zone, eastern Iran: the exhumation history of oceanic HP/LT rocks and the geological significance of presumed granulite-facies mélange rocks.

伊朗东部锡斯坦缝合带：大洋高压/低温岩石的折返历史和推测的麻粒岩相混杂岩的地质意义。

基本信息

批准号：
279126319
负责人：
Professor Dr. Michael Bröcker
金额：
--
依托单位：
Fachgebiet Geodynamik der Polargebiete
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/279126319?language=en
关键词：
Sistan Suture Zone eastern Iran

项目摘要

This proposal seeks funding for field-based research activities that aim at establishing a solid petrological, geochemical and geochronologic foundation for in-depth understanding of mélange rocks from the Sistan Suture Zone (SSZ), Iran. The study area provides the excellent opportunity to examine in detail the exhumation history of oceanic HP/LT rocks and their retrograde derivatives. The planned research activities will focus on key aspects of the SSZ evolution that demand more detailed attention: the thermal regime and the exhumation history. The proposal suggests activities which will integrate field activities, petrology, bulk-rock geochemistry, isotope geochemistry and geochronology. It is planned to apply Rb-Sr geochronology for dating the amphibolite and/or greenschist-facies event, and to use U-Pb zircon and monazite dating to determine ages recorded in presumed granulites and in chlorite schists. Fission-track (zircon, apatite) and (U-Th-Sm)/He (apatite) analyses will provide information for subsequent cooling stages. Bulk-rock geochemical and Sr-Nd isotope data will be used to fully characterize the studied sample suite. Taken together such data is a prerequisite for in-depth understanding of the geologic histories recorded by various mélange rocks that will help gaining insights into the specific subduction zone style and exhumation mechanisms. Emphasis will be placed on the following questions: Is the closure of the Sistan ocean associated with a hot subduction setting? What are the timescales and rates of exhumation? Did exhumation occur in a single short-lived event or in discontinuous episodes over a protracted time span? Which processes control exhumation? Answering of these questions will provide a test of tectonic concepts predicting fast and discontinuous exhumation for such settings. The newly gained knowledge will allow to link the cooling path and kinematic development of the SSZ to other Neotethyan suture zones, and to assess the mechanisms of suture zone dynamics. This project will advance the understanding of the subduction-exhumation events recorded in the Sistan suture and has the potential to provide further insight into the evolution of accretionary complexes.

该提案为基于现场的研究活动寻求资金，旨在建立良好的岩石学，地球化学和地球体学基础，以深入了解伊朗Sistan缝合区（SSZ）的Mélange岩石。该研究区域提供了详细检查海洋HP/LT岩石及其逆行衍生物的挖掘历史的绝佳机会。计划的研究活动将集中于SSZ进化的关键方面，该进化需要更详细的关注：热力制度和挖掘历史。该提议建议将现场活动，岩石学，散装岩石地球化学，同位素地球化学和地质学的活动整合。计划应用RB-SR年代学来与两栖石和/或绿色品种事件进行约会，并使用U-PB锆石和独居石的约会来确定预览颗粒和氯酸盐片岩中记录的年龄。裂变轨道（锆石，磷灰石）和（u-th-sm）/He（磷灰石）分析将为后续冷却阶段提供信息。散装岩石地球化学和SR-ND同位素数据将用于充分表征研究的样品套件。将这种数据汇总为深入了解各种混合岩石记录的地质历史的先决条件，这将有助于洞悉特定的俯冲区样式和挖掘机制。将重点放在以下问题上：锡斯坦海洋的关闭是否与热俯冲环境相关？挖掘的时间标准和速率是多少？发掘是否在一个短暂的事件中或在旷日持久的时间跨度中发生？哪些过程控制发掘？回答这些问题将对构造概念进行测试，以预测这些环境的快速和不连续的挖掘。新获得的知识将允许将SSZ的冷却路径和运动学发展与其他Neotethyan缝合区联系起来，并评估缝合区动力学的机制。该项目将进一步了解锡斯坦缝合线中记录的俯冲发出事件，并有可能进一步深入了解源自递观复合物的演变。