Faults and fluids in accretionary orogens

增生造山带（山带）是在数千万年至数亿年的时间里，随着大洋板块的俯冲增生，大陆和海洋的碎片（地体）被带到大陆板块边缘而形成的。这些多次碰撞在形成的山带中形成了一个复杂的断层网络（地球上基本上不透水的地壳的断裂），这些断层很容易发生后来的滑动（重新激活）。断层可以成为岩石熔体（岩浆）、流体和热量传递的有效途径，从而促进金属的流动和集中。许多矿床环境（如变形带、侵入体、盆地）发生在增生造山带断裂系统内或其附近，其中许多宿主金属被认为对加拿大未来社会至关重要（如Sn、W、Mo、In、Au、Bi、Co、U）。我的研究计划的长期目标是记录造山带上地壳的断层、流体和热记录，并将它们与地球动力学过程和矿床形成联系起来。我最近的工作集中在加拿大两侧的吸积造山带、加拿大东海岸的阿巴拉契亚山脉和加拿大西海岸的科迪勒拉山脉的同时代地质、构造和矿石系统记录。这些研究表明，与矿石相关的过程可能是由地球岩石圈地幔（地壳下面的地球层）的扰动引发的。我的短期目标（1-3）主要是在这两个造山带中验证这一假设。在接下来的五年里，我将（O1）利用野外测绘、岩石微观结构分析、岩石年代学和热年代学岩石测年方法，重建造山断裂带后增生活化期间上地壳的温度-时间和结构演化。我将（O2）在这些时期使用新方法确定断层-流体临界金属成矿关系，包括滑溜纤维和脉的U-Pb测年，断层泥粘土的K-Ar测年以及稳定和团块同位素。最后，我将通过数值模拟探讨岩石圈扰动（如俯冲的板块断裂和剥离）如何影响增生后造山带背景下上地壳的温度-时间演化。这项工作将为造山带的长期断层行为提供一个完善的框架，特别是在造山带岩石圈演化和矿床形成的背景下。结果将有助于加拿大寻找其关键矿物资源的能力。参与这项研究的HQP将与世界一流的实验室、工业界和政府合作，并将在分析研究、数据管理、共同构造地质学和矿床现场和实验室研究方法以及科学传播方面发展可转移技能。

Accretionary orogens (mountain belts) form over tens to hundreds of millions of years as continental and oceanic fragments (terranes) carried on a subducting oceanic plate accrete to a continental plate margin. These multiple collisions produce a complex network of faults (breaks in the Earth's otherwise largely impermeable crust) in the resulting mountain belts, that can be prone to later slip (reactivation). The faults can be efficient pathways for the transfer of rock melt (magma), fluids and heat, which facilitate the flux and concentration of metals. Many ore-deposit settings (e.g. deformation zones, intrusions, basins) occur within or proximal to accretionary orogen fault systems, and host metals, many of which are considered essential for Canada's future society (e.g., Sn, W, Mo, In, Au, Bi, Co, U). The long-term objective of my research program is to document the fault, fluid and thermal records of orogenic upper crust and relate them to geodynamic processes and ore-deposit formation. My recent work has focused on coeval geological, structural and ore-system records in Canada's flanking accretionary orogens, the east coast Canadian Appalachians and the west coast Canadian Cordillera. These studies suggest that ore-relevant processes may have been triggered by perturbations of the Earth's lithospheric mantle (the layer of the Earth that underlies the crust) beneath accreted terranes. My short term objectives (O1-3) are focused around testing that hypothesis in these two orogens. Over the next five years, I will (O1) reconstruct the temperature-time and structural evolution of the upper crust during post-accretionary reactivation of orogenic fault zones using field mapping, analysis of rock microstructures, and petrochronology and thermochronology rock dating methods. I will (O2) determine the fault-fluid-critical metal mineralization relationships during these periods using novel methods including U-Pb dating of slickenfibres and veins, K-Ar dating of fault gouge clay and stable and clumped isotopes. Finally, I will (O3) explore how lithospheric perturbations such as subducted slab break-off and delamination may influence the temperature-time evolution of the upper crust in a post-accretionary orogenic setting via numerical modeling. This work will result in a refined framework for long-term fault behaviour in accretionary orogens, particularly in the contexts of orogen lithosphere evolution and ore-deposit formation. Results will contribute to Canada's ability to search for its critical mineral resources. HQP involved in conducting this research will collaborate with world-class laboratories, industry, and government, and will develop transferable skills in analytical research, data management, common structural geology and ore deposits field and laboratory research methods, and science communication.