Mineralogy, petrology and isotope systematics of Proterozoic continental rift-related alkaline magmatism, Northwestern Ontario, Canada

铌、稀土矿床形成于伟晶岩、碳酸岩和某些过碱性岩浆岩等高度分异的岩浆流体中。由于稀土用于钕磁体和各种电子元件的技术应用以及铌用于钢合金的需求，北美碳酸盐岩和碱性复合物的勘探正在增加。每个铌和稀土存款是独特的，通常呈现各种铌和稀土矿物。目前的勘探方法通常基于大块岩石分析。这种方法是不够的，因为碳酸盐岩和有关的碱性岩石中的铌和稀土的矿物成分变化。重要的是要了解每个矿床的矿物学。 该项目是对来自安大略西北部的碳酸岩和相关碱性岩石进行的综合矿物学和地球化学研究，这些岩石是铌和稀土元素积极高级勘探项目的一部分。它将涉及现场矿物学特征鉴定（和矿物化学分析）、岩石学调查和矿床中示踪矿物的同位素（Nd-Sr-Hf-Pb）研究。两个西北安大略铌和稀土碳酸盐岩侵入体，草原湖碳酸盐岩复合体，和奇普曼湖碳酸盐岩岩脉和fenites），和两个铌，稀土多相碱性侵入体（Coldwell和Killala碱性复合体）将参与本研究。所有侵入体都与元古宙基韦纳湾大陆裂谷事件有着重要的关系。了解这个地质复杂地区独特的矿物学和同位素变化，将提供重要的洞察岩浆系统的来源和大规模大陆裂谷事件期间的杂岩的侵位。这既有利于勘探工业，也有利于研究元古宙基韦纳湾大陆中部裂谷事件，在那里，人们对碳酸盐岩和碱性复合体与裂谷事件的成因关系知之甚少。

Niobium and rare earth element (REE) deposits are formed from highly differentiated magmatic fluids, such as pegmatites, carbonatites, and some peralkaline igneous rocks. Exploration of carbonatite and alkaline complexes across North America is increasing due to the demand of REEs for technological applications in Nd-magnets and diverse electronic components, and Nb for steel alloys. Each Nb- and REE deposit is unique, commonly presenting a variety of Nb- and REE minerals. Current exploration methods are often based on bulk rock analysis. This method is inadequate due to the compositional variation of Nb- and REE-bearing minerals in carbonatites and related alkaline rocks. It is important to understand the mineralogy of each of the deposits. This program is an integrated mineralogical and geochemical study of carbonatites and related alkaline rocks from Northwestern Ontario that are part of active advanced exploration programs for Nb- and REEs. It will involve in-situ mineralogical characterization (and chemical analysis of minerals), petrological investigations and isotopic (Nd-Sr-Hf-Pb) studies of tracer minerals occurring in the deposits. Two Northwestern Ontario Nb- and REE carbonatite intrusions, the Prairie Lake carbonatite complex, and the Chipman Lake carbonatite dikes and fenites), and two Nb-, REE-hosted multiphase alkaline intrusions (the Coldwell and Killala alkaline complexes) will be involved in this study. All intrusions share an important relationship to the Proterozoic Keweenawan Midcontinental rifting event. Understanding the unique mineralogy and isotopic variation in this geologically complex area will provide important insights into the source of the magma systems and the emplacement of the complexes during the large-scale continental rifting event. This is both beneficial to the exploration industry, and research into the Proterozoic Keweenawan Midcontinental rifting events, where little is understood with regards to the genetic relationship of the carbonatitic and alkaline complexes to the rifting event.