Collaborative Research: Deformation and Magmatic Modification of a Steep Continental Margin, Western Idaho-eastern Oregon

合作研究：爱达荷州西部-俄勒冈州东部陡峭大陆边缘的变形和岩浆改造

• 批准号: 0844264
• 负责人: John Hole
• 金额: $ 75.52万
• 依托单位: Virginia Polytechnic Institute and State 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 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0844264&HistoricalAwards=false
• 关键词: Collaborative; Research; Deformation; Magmatic; Modification

This award is funded under the American Recovery and Reinvestment Actof 2009 (Public Law 111-5).Much of the land area of Washington, Oregon, and California was added to continental North America during the last 200 million years. Exactly how this dominantly oceanic lithosphere accreted to the continent is not well understood, although it is clear that the processes involved differed from north to south along North America's former western margin. In the Idaho-Oregon border region, the boundary between oceanic and continental lithospheres is well exposed in a very narrow zone of high deformation known as the western Idaho shear zone. This project is providing insight into how this sharp boundary formed, how it has controlled subsequent deformation and magmatism regionally, and the role it has played in the formation of North America. Because the Oregon-Idaho segment separates distinct styles of mountain building in California and the southern Canadian Cordillera, a better understanding of this complex region is critical for developing a coherent model for the tectonic evolution of western North America and ultimately helping us understand proceses by which continents are created and evolve through time.Research scientists from the University of Wisconsin, Virginia Tech, The University of Florida, and Washington State University are integrating the results of seismological, geochemical, geochronologic, and structural geologic studies in order to investigate three major issues associated with the evolution of this continental margin: 1) How do fundamental lithospheric structures, such as the continental-oceanic lithosphere boundary exposed in the western Idaho shear zone, guide subsequent deformation and magmatism?; 2) How do magmatism and extensional deformation modify (destabilize) the continental lithosphere, and at what lithospheric levels?; and 3) What are the tectonic implications of this destabilization for evolving magmatism, deformation, and lithospheric strength? A swath of broadband passive seismic instruments and a seismic refraction line will delineate the current geometry of the major geologic units and their boundaries to several hundred kilometers depth. Geochemistry and geochronology will characterize post- western Idaho shear zone magmatism to provide the timing of events and the tectonic context in which these processes occurred. Structural geology will provide the kinematic and dynamic deformation path by which the continent was modified, by defining the major tectonic boundaries and establishing the kinematic history of the major structures.In addition to the research objectives of this project, the award will support the education and training of four graduate students and eight undergraduate students distributed between the four universities, and supports an early career researcher at the University of Florida.

该奖项是根据2009年的《美国复苏与再投资法》（公法111-5）资助的。在过去的2亿年中，华盛顿，俄勒冈州的土地地区和加利福尼亚州的土地地区被添加到北美大陆。尽管很明显，沿北美以前的西部边缘从北到南部的涉及的过程很明显，但尚不清楚这种主要的海洋岩石圈的主要岩石圈。在爱达荷州 - 俄罗斯岛边界区域，海洋和大陆岩石圈之间的边界在一个非常狭窄的高变形区域露出，称为西部爱达荷州剪切区。该项目正在洞悉这种尖锐的边界如何形成，如何控制随后的变形和岩浆，及其在北美形成中的作用。因为俄勒冈州立大学的细分市场将加利福尼亚和加拿大南部的山地山脉区分开了不同的山区建筑风格，因此对这个复杂地区的更好理解对于开发西部北美构造构造的相干模型至关重要地球化学，地质学和结构地质研究是为了研究与这种大陆边缘进化相关的三个主要问题：1）如何在爱达荷州西部剪切区域中暴露于大陆岩石圈的基本岩石圈结构如何指导，引导后续的变形和岩浆症？ 2）岩浆和伸展变形如何修饰大陆岩石圈以及在哪些岩石圈水平？ 3）这种不稳定对不断发展的岩浆，变形和岩石圈强度的构造意义是什么？宽带被动地震仪器和地震折射线将描绘主要地质单元的当前几何形状及其边界为几百公里的深度。地球化学和年代学将表征西部爱达荷州剪切带岩浆岩岩岩岩，以提供事件的时间和这些过程发生的构造环境。结构地质学将通过定义主要的构造界限并建立主要结构的运动学历史来修改大陆的运动和动态变形路径。在该项目的研究目标外，该奖项将支持四个研究生的教育和培训，对四个研究生的教育和培训，八名学生在四个大学中分配了四个大学和早期的研究生，并支持了大学的职业生涯。