Collaborative Research: Dating Deformation with Titanite

合作研究：用钛矿测定形变年代

• 批准号: 1927060
• 负责人: Bradley Hacker
• 金额: $ 28.9万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1927060&HistoricalAwards=false
• 关键词: Collaborative; Research; Dating; Deformation; Titanite

Much of our understanding of the geologic history of the Earth comes from radiometric dating of Earth processes. Currently, Earth scientists have a difficult time placing narrow constraints on the precise time that a fault occurs deep within the crust of the Earth. This project combines two state-of-the-science techniques to directly date the time of faulting along a key fault zone in southeast Alaska, and thereby date when ancient earthquakes occurred. Development of this new analytical technique will enable considerable future research and understanding of how Earth materials deform. In addition, this research project will provide training and research opportunities for a female graduate student and several undergraduate students. Visits to local elementary schools will enable potential future scientists to experience the methods and results of Earth science research, with direct implications for earthquake hazards. This collaborative project consists of two principal objectives: 1) develop the mineral titanite as a tool for dating high-temperature deformation by a combined microstructural and microgeochronology approach, and 2) apply this tool to the evolution of the spectacular Coast Shear Zone and Great Tonalite Sill in the Coast Mountains orogen of southeast Alaska. Research methods will incorporate a field study to understand qualitatively the evolution of a mid- to deep crustal intra-arc shear zone and synkinematic sheeted-sill complex exposed in the Coast shear zone of Alaska and Canada. Titanite analyses will include electron-backscatter diffraction maps of titanite microstructure, and laser-ablation split-stream inductively coupled plasma maps of titanite composition that incorporate U-Pb dates. These data will allow assessment of the physical and chemical processes that affected the crystal, and the identification of crystals whose U-Pb distribution reflects high-temperature deformation. Because titanite is a widespread crustal mineral, this technique should have broad application globally and enhance our understanding of how crust deforms and orogens assemble and change through time.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

我们对地球地质历史的大部分理解都来自地球过程的辐射测定。当前，地球科学家在确切的时间内发生在地球的地壳内的确切时间上，将狭窄的限制放在狭窄的时间上。该项目结合了两种最先进的技术，可以直接与阿拉斯加东南部关键断层区域的断层时间有关，从而在发生古老地震时。这项新的分析技术的开发将使将来的研究和了解地球材料如何变形。此外，该研究项目将为女研究生和几名本科生提供培训和研究机会。访问当地小学将使潜在的未来科学家能够体验地球科学研究的方法和结果，并直接影响地震危害。该协作项目由两个主要目标组成：1）开发矿物钛矿作为通过组合的微观结构和微地质学方法来约会高温变形的工具，2）将此工具应用于壮观的海岸剪切区的演变，并在阿拉斯加东南植物的沿海植物山层中使用了大型的Tonalite山地。研究方法将纳入一项现场研究，以定性地了解深层地壳内部剪切带和在阿拉斯加和加拿大海岸剪切带中暴露的synkinematic板岩岩体复合物的演变。钛铁矿分析将包括钛铁矿微结构的电子 - 折叠式衍射图，以及结合了U-PB日期的钛铁矿组成的激光燃烧裂隙流的电感耦合等离子体图。这些数据将允许评估影响晶体的物理和化学过程，并鉴定其U-PB分布反映高温变形的晶体。由于钛铁矿是一种广泛的地壳矿物质，因此该技术应在全球范围内具有广泛的应用，并增强我们对地壳变形和蛋黄酱如何随着时间的推移组装和变化的理解。该奖项反映了NSF的法定任务，并被视为值得通过基金会的知识分子和更广泛的影响审查审查标准来通过评估来通过评估来获得支持。