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

Nb和稀土元素(REE)矿床是由高度分异的岩浆流体形成的，如伟晶岩、碳酸岩和一些过碱性火成岩。北美对碳酸盐岩和碱性络合物的勘探正在增加，这是因为稀土在稀土磁体和各种电子元件的技术应用中的需求，以及对钢铁合金对Nb的需求。每一个Nb和REE矿床都是独一无二的，通常呈现出各种Nb和REE矿物。目前的勘探方法往往以块状岩石分析为基础。由于碳酸盐岩及相关碱性岩石中含Nb和REE矿物的成分变化，这种方法是不够的。了解每个矿床的矿物学是很重要的。 该项目是对安大略省西北部碳酸盐岩和相关碱性岩石的综合矿物学和地球化学研究，这些岩石是目前正在进行的Nb-和Rees高级勘探计划的一部分。它将涉及矿物学现场表征(和矿物的化学分析)、岩石学研究和矿藏中的示踪矿物的同位素(Nd-Sr-Hf-Pb)研究。安大略省西北部的两个Nb和REE碳酸盐岩侵入体、草原湖碳酸盐岩杂岩和奇普曼湖碳酸盐岩岩脉和辉长岩，以及两个Nb、REE赋存的多相碱性侵入岩(Coldwell和Killala碱性杂岩)将参与本次研究。所有侵入作用都与元古界Keweenawan中大陆裂谷事件有重要关系。了解这一地质复杂地区独特的矿物学和同位素变化，将为了解大规模大陆裂谷事件期间岩浆系统的来源和杂岩的侵位提供重要的见解。这既有利于勘探行业，也有利于元古界Keweenawan中大陆裂谷事件的研究，目前对碳酸盐岩和碱性杂岩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.