Magmatism, sedimentation and the uranium mineral system in the Paleoproterozoic core of Canada

前寒武纪地盾构成了加拿大地壳的重要组成部分，许多太古宙（大约25亿年的历史）的组成部分在大约18亿年前的一次灾难性碰撞中结合在一起，这次碰撞被称为跨哈德逊造山运动，它被保存在一个从萨斯喀彻温省延伸到巴芬岛的线性带中。这次碰撞与岩石圈板块的运动有关，形成了一个山脉，其规模可能与今天的喜马拉雅山脉相同。在碰撞发生之前，不同地壳元素之间发生了复杂的相互作用，产生了岩浆、沉积物和构造。这项研究的部分目的是揭开18亿年前大碰撞之前不同地壳块之间的相互作用，重点是萨斯喀彻温省和马尼托巴省北部暴露的岩石，包括一些研究生和本科生在实地测绘和取样，以及应用现代分析技术分析微量元素和同位素。为了了解地壳和地幔是如何相互作用的，有必要确定地壳和地幔不同部分的组成。此外，加拿大中部前寒武纪岩石中蕴藏着世界级的铜、锌、金、铀和稀土元素热液矿床，其形成与山带演化密切相关。

The Precambrian Shield makes up a significant portion of the crust in Canada, and many of the Archean (>2.5 billion years old) components were joined together about 1.8 billion years ago during a cataclysmic collision, called the Trans-Hudson orogeny, that is preserved in a linear belt that extends from Saskatchewan to Baffin Island. The collision, which was related to the motion of lithospheric plates, formed a mountain range that was probably of the same scale as the present-day Himalayas. In the lead up to the collision, there were complex interactions between different crustal elements which generated magmas, sediments, and structures. The aim of part of this research, which involves mapping and sampling in the field by a number of graduate and undergraduate students, and the application of modern analytical techniques for the analysis of trace elements and isotopes is to unravel the interaction between different crustal blocks just prior to the major collision 1.8 billion years ago, with a focus on the well-exposed rocks in northern Saskatchewan and Manitoba. It will be necessary to define the composition of different parts of the crust and mantle in order to understand how they interacted. In addition the Precambrian rocks in central Canada host world-class hydrothermal deposits of copper, zinc, gold, uranium, and rare earth elements, and their formation is intimately related to the evolution of the mountain belt. The research will focus on the youngest igneous rocks (about 1.85 to 1.82 billion years old) that formed during this mountain-building event, partly because this represents the most complex part of this event, and will provide a chemical and isotopic “fingerprint” of the parts of the crust and mantle that might have been involved in the formation of these rocks. In addition, the sedimentary rocks that formed in basins as continental collisions were occurring preserve zircons as detrital minerals, and they record the age and character of the source regions for these sediments. The mountain belt was then eroded, and sediments were deposited in the uranium-rich Athabasca Basin, under which is a zone of alteration that may represent an ancient weathered profile. This will be examined to determine its origin, and whether this might be an important source of metals, including uranium, for the younger mineral deposits. Direct outcomes of all this work will be student theses and journal papers, and well-trained new geoscientists to work in academia, government or the Canadian minerals industry.