Investigating novel metasomatic processes at the Ilimaussaq Complex, South Greenland

研究格陵兰岛南部伊利毛萨克综合体的新交代过程

• 批准号: 2235691
• 金额: --
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2235691
• 关键词: Investigating; novel; metasomatic; processes; Ilimaussaq

The kakortokites of the Ilimaussaq Complex in South Greenland demonstrate world-class layering in agpaitic nepheline syenites. Each rhythmic layer is sub-horizontal in aspect and considered undeformed since their formation ~1160 Ma ago. They host eudialyte group minerals which contain elements of high economic value (e.g., Zr, Ta, Nb, and rare earth elements). The origin of the layering and mineral enrichment is widely debated. This is further complicated by widespread metasomatic alteration and hydrothermal overprint. The fundamental aim of this PhD project is to constrain whether the macroscale layering can be attributed to magmatic or metasomatic/hydrothermal processes and to what extent this had on the mineral enrichment. The thesis comprises three chapters, respectively focusing on: (1) the petrology and geochemistry of the magmatic, late-stage metasomatic, and hydrothermal phases from within the kakortokites; (2) the geochemical effects of the metasomatic alteration on the mineralogy; and (3) the source of the metasomatic fluids responsible for the alteration using stable isotope geochemistry. This work will further improve our understanding on the formation of layered intrusions and their economically important metal ore deposits.

格陵兰南部伊利毛萨克杂岩中的卡科尔托克岩显示出世界级的霞长石正长岩分层。每个韵律层在外观上都是近水平的，并且被认为是自其形成以来未变形的~1160 Ma前。它们含有含有高经济价值元素的正渗析族矿物（例如，Zr、Ta、Nb和稀土元素）。分层和矿物富集的起源是广泛争论的。广泛的交代蚀变和热液叠加使这一问题更加复杂。这个博士项目的基本目的是限制宏观分层是否可以归因于岩浆或交代/热液过程，以及在多大程度上这对矿物富集。论文共分三章，分别研究了卡科尔托基岩中岩浆、晚期交代和热液阶段的岩石学和地球化学特征;交代蚀变对矿物学的地球化学效应;利用稳定同位素地球化学方法研究交代流体的来源。这项工作将进一步提高我们对层状侵入体的形成及其重要的经济金属矿床的认识。