Collaborative Research: Developing a Practical and Quantitative Method for Measurement of Metamorphic Porphyroblast Crystallization Kinetics and Strain Rate

合作研究：开发一种实用且定量的方法来测量变质斑母细胞结晶动力学和应变率

• 批准号: 0911582
• 负责人: Ethan Baxter
• 金额: $ 10.5万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0911582&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; Practical; Quantitative

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." This project, which is a collaboration between researchers at Western Washington University, the University of Alabama at Tuscaloosa, and Boston University, is focused on improving our understanding of what happens when rocks are heated, pressurized, and deformed deep within the Earth's crust, a process (metamorphism) that is occurring every day under our feet. The researchers strive to understand the rates at which rocks are deformed and at which new crystals grow during metamorphism. These basic parameters of metamorphism are very poorly known. The researchers will develop and test a new method for determining these rates on rocks from Townshend Dam, VT, which were metamorphosed about 380 million years ago during a collision between North America and a micro-continent to the east. The study will estimate the rates of metamorphism and deformation during this collision (and by extension, other similar collision events), but more importantly, the project will develop a new method by which these and related aspects of metamorphism can be studied in other areas by other researchers in the future. The investigation will focus on garnet, a commonly formed metamorphic mineral that tends to record details of its environment as it grows. The research relies on recent advances in Sm-Nd radiometric dating of tiny volumes of garnet. The investigators will date well-characterized parts of garnet crystals in a rock to link the garnet chemistry to the time of garnet growth. The crux of the method is that it will allow numerous indirect dates to be easily obtained by reference to the arduously obtained time-chemistry link. The specific questions being studied are: What are metamorphic nucleation rates and how do they vary with time? What are growth rates for individual crystals and how do they vary over the course of a crystal's growth? How fast are rocks deformed during continental collisions, and is that deformation continuous or episodic? How fast are rocks heated and loaded during collisions? Finally, the study will provide the first data set of its kind, against which theoretical models of nucleation and growth can be tested.

“该裁决是根据2009年《美国复苏与再投资法》（公法111-5）资助的。”该项目是西部华盛顿大学，阿拉巴马大学塔斯卡卢萨大学和波士顿大学的研究人员之间的合作，致力于提高我们对每天都在我们脚下发生的过程（Metamorphist）在地球上加热，加压和变形时发生的事情的理解。研究人员努力了解岩石变形的速率以及新晶体在变质过程中生长的速度。这些变质的基本参数众所周知。研究人员将开发并测试一种新方法，以确定弗吉尼亚州汤申（Townshend）大坝的岩石上的这些率，大约3.8亿年前，在北美与东方微型陆地上的碰撞期间，它们被变成了3.8亿年。该研究将估计这种碰撞期间变质和变形的速率（以及通过扩展，其他类似的碰撞事件），但更重要的是，该项目将开发一种新方法，通过该方法可以通过这些方法在未来的其他研究人员中可以在其他领域研究变质的这些和相关方面。该调查将集中于石榴石，石榴石是一种通常形成的变质矿物，倾向于记录其生长的环境细节。该研究依赖于小石榴石的SM-ND辐射测定的最新进展。研究人员将在岩石中将石榴石晶体的特征良好的部分与石榴石化学联系在一起，以将石榴石化学连接到石榴石生长时代。该方法的关键是，它将允许通过参考艰苦获得的时间化学链接来轻松获得许多间接日期。所研究的具体问题是：变质成核率是多少？随时间变化？单个晶体的增长率是多少？它们在晶体的生长过程中如何有所不同？在大陆碰撞期间，岩石变形的速度有多快，变形是连续还是发作的？碰撞期间加热和装载的速度速度多快？最后，该研究将提供同类数据集的第一个数据集，可以测试成核和生长的理论模型。