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.

早期大陆地壳唯一的原始遗迹是高度改造的片麻岩中的锆石和碎屑锆石颗粒。因此，我们对早期大陆地壳演化的了解主要依赖于从这些极其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锆石群作为大陆地壳形成记录的可靠性。区域焦点是维多利亚州北部的威尔逊地体 (WT)，这里横跨前大陆弧的独特中地壳轮廓从会聚板块边缘暴露到克拉通基底。在那里，可以在靠近前缘的地方发现I型花岗岩，它们可能是由地幔衍生的弧岩和同化的地壳物质的分异或部分熔融形成的。在克拉通地区，它们转变为 S 型花岗岩，这是由沉积岩部分熔化为长英质结晶岩而形成的。我们将使用 U-Pb 年龄、O 和 Hf 同位素、U-Hf-Yb-Y 微量元素系统学以及花岗岩锆石的包裹体组合，并将这些与主岩的岩石学相关联。除了作为围岩历史的可靠记录进行评估之外，WT 花岗岩中的锆石还为跨大陆边缘和岛弧的花岗岩演化提供了见解。在区域上，该项目将估计有多少前寒武纪地壳（如果有）位于 WT 岩石之下，或者 WT 是否仅由源自深部大陆边缘盆地的副片麻岩组成。