Flow of rocks

岩石的流动

• 批准号: 7419-2006
• 负责人: Williams, Paul
• 金额: $ 4.52万
• 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: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=389520
• 关键词: Flow; rocks

The earth's crust is in a state of flux as the plates slowly move relative to one another.  They only move centimetres per year, but over geological time this adds up. For example, 1 cm/year is equivalent to 1,000 km in 100,000,000 years. This is a reasonable time-span for the development of a mountain chain by the collision of two plates. For a plate to move, its base and edges have to deform. Movement near the surface is accommodated by fracturing (faulting), which may result in earthquakes. At depth, due to pressure, it is accommodated  by ductile flow; the crystalline rock flows as a solid, without fracturing. The hotter the rock the faster it flows. The bending of a candle standing in the sun is a ductile process. The behaviour of glaciers is similar to that of rocks, they flow slowly as a solid at depth, and form faults (crevasses) near the surface. Also, their flow is considerably faster in warm southern Canada than in frigid Antarctica. I am interested in the mechanisms responsible for deformation at all scales, from plate to microscopic. The mechanisms are influenced by such factors as: rock properties, temperature, confining pressure, rate of deformation and boundary conditions (e.g. plates colliding, or moving apart). These factors determine the characteristics of the deformed rock, and by examining the characteristics, I reconstruct the deformation history. For example the fissility of slate is a product of the deformation history; a similar history at higher temperature produces a schist. My interest is in unraveling the deformation history of selected areas (currently in the Canadian Cordillera), in order to understand the general processes and  basic principles. My modus operandi involves field observation, theoretical considerations, numerical and physical experimentation, determination of past temperature and pressure, and dating of the various stages in the history. Work of this type is fundamental to understanding plate tectonics and related phenomena.

地壳处于一种不断变化的状态，因为板块之间的相对运动缓慢，它们每年只移动几厘米，但随着地质年代的推移，这种移动会累积起来。例如，1厘米/年相当于100，000，000年1，000公里。这是两个板块碰撞形成山脉的合理时间跨度。板块要移动，其底部和边缘必须变形。地表附近的运动通过断裂（断层）来调节，这可能导致地震。在深处，由于压力，它被韧性流动所容纳;结晶岩石作为固体流动，没有破裂。岩石温度越高，流动速度越快。蜡烛在阳光下的弯曲是一个可延展的过程。冰川的行为与岩石相似，它们在深处像固体一样缓慢流动，并在表面附近形成断层（裂缝）。此外，它们在温暖的加拿大南部的流动速度要比在寒冷的南极洲快得多。我感兴趣的机制，负责变形在所有规模，从板微观。这些机制受到以下因素的影响：岩石性质、温度、围压、变形速率和边界条件（例如板块碰撞或分离）。这些因素决定了变形岩石的特征，通过检查这些特征，我重建了变形历史。例如，板岩的裂变性是变形历史的产物;在较高温度下，类似的历史产生了片岩。我的兴趣是解开选定地区（目前在加拿大科迪勒拉）的变形历史，以了解一般过程和基本原则。我的工作方式包括实地观察、理论考虑、数值和物理实验、确定过去的温度和压力以及确定历史各个阶段的年代。这类工作是理解板块构造和相关现象的基础。