Formation of magmatic oxide deposits

岩浆氧化物矿床的形成

• 批准号: RGPIN-2015-05924
• 负责人: Dare, Sarah
• 金额: $ 0.13万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=648655
• 关键词: Formation; magmatic; oxide; deposits

Magmatic oxide deposits are important sources of titanium (Ti) and vanadium (V), extracted from oxide minerals (ilmenite and magnetite, respectively), and phosphorous (P), from apatite. The crystallization and accumulation of these minerals occurred in ancient magma chambers, termed igneous intrusions, in the Earth's crust. Yet many of the fundamental processes involved in the formation of this class of mineral deposit and their host intrusions remain unresolved and are highly debated over. My research aim is to improve our understanding of these processes using an innovative approach: the analysis of trace elements in the ore minerals themselves. Over the next 5 years I aim to (1) develop new theories to describe the trace element content of iron oxides and apatite using the new technique of laser ablation ICP-MS, (2) determine the geological processes that control and modify the trace element content of these minerals and (3) use trace element chemistry of ore minerals to enhance our understanding of oxide deposits from more complex geological settings, for example where genetic relationships between oxide mineralization and host rocks is unclear. This funding will support an early career scientist to build a new high-caliber research group and provide quality training of Highly Qualified Personnel in the fields of analytical geochemistry, igneous petrology and mineral deposits. ***Mineral chemistry provides important information on processes forming igneous rocks and their ore deposits, but it has been underexplored for trace elements due to limitations in analytical capabilities. However, it is now possible to determine, at the grain scale, a much larger number of trace elements than before using the technique of laser ablation ICP-MS. In order for this technique to become common practise it is critical to understand the processes that control the abundance of trace elements in minerals. My initial work on trace element chemistry of magnetite has demonstrated the potential of this technique for understanding, and tracking, processes involved in forming some magmatic mineral deposits. It is expected that this pioneering research program on oxide deposits will provide additional constraints on i) when and how the ore minerals formed, (ii) how they became concentrated into mineralized layers/lenses and (iii) tectonic setting of oxide deposits and their intrusions. This research will also have impact and significance on a broad range of disciplines because the chemistry of detrital grains of iron oxides and apatite can be used to `fingerprint' different rock types and thus indicate the provenance of sedimentary rocks and surficial sediments. The latter is of great interest to the Canadian economy for the exploration of new mineral resources.

岩浆氧化物矿床是从氧化物矿物（分别为钛铁矿和磁铁矿）中提取的钛（Ti）和钒（V）以及从磷灰石中提取的磷（P）的重要来源。这些矿物的结晶和积累发生在地壳中的古老岩浆房中，称为火成岩侵入体。然而，这类矿物存款及其寄主侵入体的形成所涉及的许多基本过程仍然没有得到解决，并存在很大的争议。我的研究目标是通过一种创新的方法来提高我们对这些过程的理解：分析矿石矿物本身中的微量元素。在接下来的5年里，我的目标是（1）开发新的理论来描述铁氧化物和磷灰石的微量元素含量，使用激光消融ICP-MS的新技术，（2）确定控制和修改这些矿物的微量元素含量的地质过程，（3）使用矿石矿物的微量元素化学来提高我们对更复杂地质环境中氧化物矿床的理解，例如，氧化物矿化和寄主岩石之间的成因关系不清楚。这笔资金将支持早期职业科学家建立一个新的高素质研究小组，并在分析地球化学，火成岩学和矿床学领域提供高素质人才的优质培训。* 矿物化学提供了关于火成岩形成过程及其矿床的重要信息，但由于分析能力的限制，对微量元素的研究不足。然而，现在可以确定，在颗粒尺度上，比以前使用激光烧蚀ICP-MS技术的微量元素的数量大得多。为了使这种技术成为普遍的做法，它是至关重要的，以了解控制矿物中微量元素丰度的过程。我对磁铁矿微量元素化学的初步研究已经证明了这种技术在理解和跟踪一些岩浆矿床形成过程中的潜力。预计这一关于氧化物矿床的开创性研究计划将提供以下方面的额外限制：（i）矿石矿物何时以及如何形成;（ii）它们如何集中成矿化层/透镜体;（iii）氧化物矿床及其侵入体的构造环境。这项研究还将对广泛的学科产生影响和意义，因为氧化铁和磷灰石碎屑颗粒的化学性质可用于“识别”不同的岩石类型，从而表明沉积岩和表层沉积物的来源。后者对加拿大经济有很大的兴趣，因为它可以勘探新的矿产资源。