The source of fluids associated with critical-mineral formation in the Mulgrave Lake, Barrington, Shelburne, and Port Mouton plutons, Nova Scotia

拟议研究的目标是了解在新斯科舍省形成关键元素矿藏所需的过程。为了实现我们的目标，我们计划：(1)对南山岩基主体以南和以东的深成岩中的关键矿物进行编目和共生；(2)利用我们的原位SIMS技术分析与Nb、Li等关键元素共生或赋存的云母/长石的氢、氧同位素组成，以确定流体的来源(岩浆与热液)；(3)使用Ar-Ar确定这些云母/长石的年龄；(4)分析这些侵入岩的整体稀土元素(REE)含量，以确定它们是否具有独特的稀土元素模式，可作为勘探工具。我们的研究将集中在富Nb的马尔格雷夫湖岩体和富Be-Mo的Mouton港、Shelburne和Barrington Passage深成岩体及其伴生伟晶岩。新斯科舍省地质调查局(NSGS)将使用这些数据最终完善新斯科舍省关键元素矿床的地质和地球化学模型。数据解释和列报包括统计分析，其中包括矿物学和地球化学数据的空间和时间关系，确定导致成矿的关键过程，以及估计产生关键元素矿石所需的流体事件持续时间。这项工作将极大地促进我们对赋存这些矿床的火成岩系统的了解，特别是对输送、浓缩和变质关键元素的过程的了解。拟议中的研究将培养1名关键元素矿床硕士和1名本科生。NSGS的地质学家将为这些学生的野外工作技术培训做出贡献。

The goal of the proposed research is to provide an understanding of the processes required to form critical element deposits in Nova Scotia. To achieve our goal, we plan to: (1) develop an inventory and paragenesis for the critical minerals in the plutons south and east of the main body of the South Mountain Batholith; (2) analyze the H and O isotopic composition of the micas/feldspars that are associated with or host critical elements such as Nb and Li, using our in situ SIMS technique to determine the source of the fluid (magmatic vs. hydrothermal); (3) date these micas/feldspars using Ar-Ar to determine the timing of these fluids; and (4) analyze the bulk rare earth elements (REE) contents of these intrusive rocks to determine if they have unique REE patterns that can be used as an exploration tool.Our research will focus on the Nb-rich Mulgrave Lake pluton and the Be-Mo-rich Port Mouton, Shelburne, and Barrington Passage plutons and associated pegmatites. The Nova Scotia Geological Survey (NSGS) will use these data to ultimately refine the geological and geochemical models for critical element deposits in Nova Scotia. Data interpretation and presentation include statistical analyses that incorporate both spatial and temporal relations of the mineralogical and geochemical data, identification of key processes that resulted in ore formation, and estimates of the duration of fluid events required to generate critical element ores. This work will significantly contribute to our knowledge of igneous systems that host these deposits, and in particular the processes that transport, concentrate, and modify critical elements. The proposed research will train 1 MSc student and 1 undergraduate student in critical element ore deposits. Geologists from the NSGS will contribute to the training of these students in field work techniques.