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.

早期陆壳的唯一原始残留物是高度改造的片麻岩中的锆石和碎屑锆石颗粒。因此，我们对早期陆壳演化的认识主要依赖于从这些极具抗性和坚固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作为大陆地壳形成记录的锆石种群的可靠性。区域焦点是维多利亚州北部的威尔逊地体(WT)，在那里，横跨前大陆弧的独特的中地壳剖面从会聚的板块边缘暴露到克拉通基底。在前缘附近发现了地幔弧岩和同化地壳物质的分异或部分熔融形成的I型花岗岩类。向克拉通过渡为S型花岗岩类，是沉积-长英质结晶岩部分熔融的结果。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微量元素系统学和包裹体组合，并将其与围岩岩石学进行对比。除了被认为是寄主岩石史的可靠记录外，来自WT花岗岩类的锆石还为大陆边缘和岛弧的花岗岩类演化提供了洞察。在地区上，这个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片麻岩组成。