Conditions, rates and mechanisms of fundamental metamorphic processes

基本变质过程的条件、速率和机制

• 批准号: RGPIN-2015-03829
• 负责人: Gaidies, Fred
• 金额: $ 1.97万
• 依托单位: Carleton University
• 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=651412
• 关键词: Conditions; rates; mechanisms; fundamental; metamorphic

The origin of rock texture and microstructure is one of the least understood aspects of metamorphic petrology. Yet it is known that it drastically influences some of the most elemental properties of Earth's crust such as its behavior during plastic deformation, the way it transmits seismic waves, or the rate with which thermal anomalies form and dissipate in response to tectonic processes. Funding is requested for research that will lead to a new level of understanding of the fundamental processes that govern the formation of rock texture and microstructure. This research will integrate detailed petrographic and geochronological investigations with equilibrium and kinetic modelling to quantify the rates and pressure, temperature and chemical conditions of these fundamental processes that include nucleation, crystal growth, diffusion and mineral dissolution.***In the past, an approach to chemical equilibrium was utilized to estimate the conditions of rock formation. However, recent research by the applicant and coworkers induced the question whether the disequilibrium required for rock-forming processes may be larger than previously assumed which would have important implications for the way rock-forming conditions are estimated and how these estimates are interpreted. A particular focus of the proposed research will be to quantify the departure from chemical equilibrium required for metamorphic processes, and how this depends on the interplay of interface and strain energy and directed stress and metamorphic mineral reaction kinetics. This research will help to evaluate and develop new constraints on important tectonic processes ranging from the nature and rates of mountain belt formation to the mechanisms of flow of semi-viscous rocks in Earth's mid-crust.***Major questions to be addressed by the research are: (1) What is the order of magnitude of the key parameters that impact on rock texture and microstructure formation? (2) How are these key parameters related to each other and how do they depend on changes of the metamorphic environment during geological processes? (3) What is the link between these parameters, rock microstructure, and large-scale tectonic processes? Research on the interplay and magnitudes of the key parameters for rock microstructure formation is still in its infancy but required to advance our understanding of the role of chemical reaction kinetics in geological systems. The proposed research will increase the competitiveness of Canada's earth science sector contributing to public's intrinsic interest in minerals and rocks and how they form. Direct applications of that research will provide links to the resource extraction industries which form an important segment of the Canadian economy.**

岩石质地和微观结构的起源是变质岩石学最了解的方面之一。然而，众所周知，它极大地影响了地壳的某些最元素特性，例如其在塑性变形过程中的行为，传输地震波的方式或热异常形成并响应构造过程的速率。要求进行资金进行研究，这将导致对控制岩石质地和微观结构形成的基本过程的新水平。这项研究将与平衡和动力学建模相结合，以量化这些基本过程的速率，压力，温度和化学条件，包括成核，晶体生长，扩散和矿物质溶解。但是，申请人和同事的最新研究提出了一个问题，即岩石形成过程所需的不平衡是否可能比以前假设的要大，这对估计岩石形成条件的方式以及如何解释这些估计的方式具有重要意义。拟议的研究的一个特殊重点是量化变质过程所需的化学平衡的偏离，以及这如何取决于界面和应变能的相互作用以及定向应力以及变质矿物质反应动力学。这项研究将有助于评估和开发有关重要的构造过程的新约束，从山带形成的性质和速率到地球中壳中半掩盖岩石流的机制。 （2）这些关键参数如何相互关系，它们如何取决于地质过程中变质环境的变化？ （3）这些参数，岩石微观结构和大规模构造过程之间有什么联系？关于岩石微结构形成的关键参数的相互作用和大小的研究仍处于起步阶段，但需要促进我们对化学反应动力学在地质系统中的作用的理解。拟议的研究将提高加拿大地球科学领域的竞争力，从而促进公众对矿物和岩石的内在兴趣及其形成。该研究的直接应用将提供与构成加拿大经济重要部分的资源提取行业的联系。**