Entwicklung der Mineralchemie und Einschlussparagenesenen von Zirkonen aus I- bis S-Typ Granitoiden des Wilson Terranes von Nord Viktoria Land (Antarktika): Zirkon als Monitor einer dynamischen Entstehung kontinentaler Kruste

北维多利亚地区（南极洲）威尔逊地体的 I 型至 S 型花岗岩的锆石矿物化学和包裹体共生发展：锆石作为大陆地壳动态形成的监测器

• 批准号: 238113199
• 负责人: Professor Dr. Timm John
• 金额: --
• 依托单位: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/238113199?language=en
• 关键词: Entwicklung; der; Mineralchemie; und; Einschlussparagenesenen

The only pristine remnants of early continental crust are zircons in highly reworked gneisses, and detrital zircon grains. Therefore, our knowledge about the evolution of early continental crust mainly relies on the chemical composition and geochronological data obtained from these extremely resistant and robust minerals. The central aim of this project is to investigate the reliability of zircon populations as record of continental crust formation. Regional focus is the Wilson Terrane (WT) in northern Victoria Land, where a unique mid-crustal profile across a former continental arc is exposed from the convergent plate margin into the cratonic basement. There, I-type granitoids, which presumably were formed by differentiation or by partial melting of mantle derived arc rocks and assimilated crustal material, can be found close to the former margin. Craton-wards, they transition to S-type granitoids, which result from partial melting of sedimentary to felsic crystalline rocks. We will use U-Pb ages, O and Hf isotopes, U-Hf-Yb-Y trace-element systematics, and inclusion assemblages of the granitoid zircons and correlate these with the petrology of the host rock. In addition to their evaluation as reliable records of host rock history, zircons from the WT granitoid also offer insight to granitoid evolution across continental margins and island arcs. Regionally, this project will estimate how much Precambrian crust, if any, underlies WT rocks, or whether the WT instead is composed exclusively of paragneiss derived from a deep continental margin basin.

早期大陆地壳的原始残余物只有高度改造的片麻岩中的锆石和碎屑锆石颗粒。因此，我们对早期大陆地壳演化的认识主要依赖于从这些极具抗性和坚固性的矿物中获得的化学成分和年代学数据。该项目的中心目标是调查锆石种群作为大陆地壳形成记录的可靠性。区域焦点是维多利亚地北部的威尔逊地（Wilson Terrane， WT），在那里，一个独特的中地壳剖面从会聚板块边缘穿过前大陆弧进入克拉通基底。在前缘附近可发现i型花岗岩，可能是由地幔弧岩与同化的地壳物质分异或部分熔融形成的。向克拉通方向转变为s型花岗岩，是沉积-长英质结晶岩部分熔融形成的。我们将使用花岗岩类锆石的U-Pb年龄、O和Hf同位素、U-Hf-Yb-Y微量元素系统和包裹体组合，并将这些与寄主岩石的岩石学相关联。除了作为寄主岩石历史的可靠记录之外，来自WT花岗岩类的锆石还提供了对大陆边缘和岛弧花岗岩类演化的深入了解。从区域上看，该项目将估计有多少前寒武纪地壳（如果有的话）在WT岩石下面，或者WT是否完全由来自深大陆边缘盆地的副长岩组成。