Deformation of the Earth: From Processes to Phenomena

地球变形：从过程到现象

• 批准号: RGPIN-2019-04423
• 负责人: White, Joseph
• 金额: $ 1.82万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751193
• 关键词: Deformation; Earth; Processes; Phenomena

The research program seeks to understand processes by which rocks deform through consideration of natural examples, deformation experiments and theory. Particular interests are the triggers and mechanisms by which tectonic regions cycle between seismic (earthquakes) and aseismic (flow) deformation. Individual projects typically comprise combinations of fieldwork with laboratory analysis undertaken primarily by research students (undergraduate and graduate) as part of their disciplinary training. Field work includes classical geological mapping to determine the composition and geometry of distinct tectonic regimes, aided in turn by remote imaging such enhanced photogrammetry with drones, and LIDAR (light detection and ranging). Data are then integrated into 3-dimensional models of the geological structures. Analytical techniques range from optical (light) microscopy and scanning electron microscopy (SEM) to characterize textures at the scale of centimetres to micrometres (1 thousandth of a millimeter), and electron microprobe (EMP) for grain-scale chemical analysis. Electron beam scanning diffraction (EBSD) at the latter scales is capable of discerning not only compositional variations, but also crystallographic orientation differences among grains that are used to infer the progress of deformation "frozen" into the rock texture. A technique central to the research is transmission electron microscopy (TEM). TEM is capable of imaging mineral grains and particles to the nanometer scale (1 millionth of a millimeter), a necessary requirement for analyzing fault rocks in which particles often approximate this size. Because the ratio of surface area to volume for nanoparticles is so much greater than "normal" materials, it is not appropriate to simply extrapolate processes (diffusion, reactions, particle deformation) from standard observations to the ultra-fine-grained materials. Hence, TEM is able to acquire images, crystallographic data and chemical information at the scale needed to address the fundamental processes within deformed rocks. Imaging of 3-dimensional porosity and textural attributes is achieved by microCT x-ray analysis.    The research program relates to understanding dynamics of Earth seen as earthquakes, volcanoes, the formation of economic mineral deposits by fluid-rock interaction focussed along ancient faults and shear zones Although earthquake hazards are largely concentrated along the west coast of Canada, there is an additional indirect effect of hazard through financial losses by the domestic insurance industry and foreign aid and disaster assistance related to external disasters such as the 2010 Haiti earthquake. Reaction to such events argues for investment in systematic study of such phenomena in support of better predictive models.

该研究计划试图通过考虑自然例子、变形实验和理论来了解岩石变形的过程。特别感兴趣的是构造区在地震(地震)和非地震(流动)变形之间循环的触发因素和机制。个别项目通常包括主要由研究生(本科生和研究生)进行的实地调查和实验室分析相结合，作为其学科培训的一部分。实地工作包括经典的地质测绘，以确定不同构造体制的组成和几何形状，进而借助遥感成像，如无人机增强的摄影测量和激光雷达(LIDAR)。然后，数据被整合到地质结构的三维模型中。分析技术的范围从光学(光)显微镜和扫描电子显微镜(扫描电子显微镜)，以表征厘米到微米(千分之一毫米)的纹理，以及电子探针(EMP)，用于颗粒尺度的化学分析。在后一种尺度上的电子束扫描衍射(EBSD)不仅能够识别成分变化，而且能够识别颗粒之间的结晶取向差异，用于推断变形冻结到岩石结构中的过程。这项研究的核心技术是透射式电子显微镜(TEM)。TEM能够将矿物颗粒和颗粒成像到纳米级(百万分之一毫米)，这是分析颗粒通常接近这种大小的断层岩的必要要求。由于纳米粒子的比表面积与体积之比比“普通”材料大得多，简单地从标准观测到超细颗粒材料的过程(扩散、反应、颗粒变形)是不合适的。因此，透射电子显微镜能够获得图像、结晶学数据和所需规模的化学信息，以解决变形岩石中的基本过程。通过MicroCT X射线分析实现了三维孔隙度和纹理属性的成像。尽管地震灾害主要集中在加拿大西海岸，但通过国内保险业的财务损失以及与2010年海地地震等外部灾害有关的外国援助和灾害援助，还有一种额外的间接灾害影响。对这类事件的反应需要投资于对这类现象的系统研究，以支持更好的预测模型。