EAGER: Collaborative Research: Mantle fluid contribution to springs along the Denali Fault System: Constraints on the crustal scale nature of the main strand and splays

EAGER：合作研究：地幔流体对德纳里断层系统沿线泉水的贡献：对主链和斜张地壳尺度性质的限制

• 批准号: 2016338
• 负责人: Dennis Newell
• 金额: $ 4.23万
• 依托单位: Utah State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2016338&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Mantle; fluid

The Denali Fault in Alaska is a 2000-km-long, active, predominately horizontal motion (strike-slip) fault zone associated with the boundary between the North American and the Pacific tectonic plates. Fault zones are breaks in the Earth’s crust that can act as conduits for transport of water from great depths (20 miles). Major questions exist about how deeply this fault penetrates into the crust, how the multiple strands of the fault are connected at depth, and how the changes in the style of faulting along its trace impact the circulation of deep groundwater. To inform these unknowns, this study will examine the isotope geochemistry of springs that discharge along the Denali fault zone. Results will improve the understanding of the Denali Fault, particularly with respect to the depth and interconnectedness of fault strands, with important implications for earthquake hazards and the distribution of geothermal and mineral resources. This study fosters a new interdisciplinary collaboration between investigators in Alaska and Utah, and advances education and training for undergraduate students, including those from underrepresented groups.This one-year project will examine the helium isotope signature of springs discharging along the Denali Fault system and along splay thrust faults. The fault system transitions east-to-west from a transform fault to a continental strike-slip fault, and provides a system to test hypotheses on the nature of continental strike-slip faults and splay thrust faults as potential conduits for mantle-derived fluids. Helium isotope (3He/4He), carbon, oxygen, and hydrogen stable isotope, and water chemistry data from springs will constrain the contribution of mantle-derived fluids to test competing geophysics models on variations in the crustal scale of the Denali Fault system, the depth splay faults connect with the master strand of the Denali Fault, and possible influences of the underlying subducting slab geometry on fluid isotopic composition. For this exploratory study, ten springs were selected along the trace of the Denali Fault system in Alaska, including six CO2-rich springs that deposit travertine to maximize capturing signals from deep flow paths. In addition to advancing understanding of the structural and geochemical record of fluid-fault interaction, this study provides a framework for future helium isotopic analysis of additional springs along the Denali Fault system, other regional structures, and the tectonic-magmatic regime responsible for geothermal resources across Alaska.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.

阿拉斯加的Denali断层是2000公里长的，活跃的，主要的水平运动（滑滑）断层区，与北美和太平洋构造板之间的边界相关。断层区是地壳中的断裂，可以充当从大深处（20英里）运输水的导管。关于此断层渗透到地壳中的深度，断层的多链如何连接到深度以及断层沿其痕量沿痕量的变化如何影响深地下水的循环中的变化，存在着主要的问题。为了告知这些未知数，本研究将检查沿Denali断层区排出的弹簧的同位素地球化学。结果将提高对Denali断层的理解，特别是在断层链的深度和相互联系方面，对地震危害以及地热和矿物资源的分布具有重要意义。研究促进了阿拉斯加和犹他州的研究人员之间的新跨学科合作，并为本科生提供了教育和培训，包括来自代表性不足的小组的教育和培训。这项为期一年的项目将研究沿着Denali断层系统沿着Springs排出的氦同位素签名，并沿着Splay pharust Presss出现。断层系统从变换断层向东过渡到连续滑动断层，并提供了一个测试假设的氦同位素（3HE/4HE），碳，氧气和氢稳定的同位素的系统，以及来自Springs的水化学数据，将限制竞争性的依从性地等级的范围，从Splay断层与Denali断层的主链连接在一起，并可能影响基础俯冲板几何在流体同位素组成上的影响。在这项探索性研究中，沿着阿拉斯加的Denali断层系统的痕迹选择了十个弹簧，其中包括六个富含二氧化碳的弹簧，这些弹簧沉积石灰华，以最大程度地捕获深层流动路径的捕获​​信号。除了进一步了解流体过失互动的结构和地球化学记录外，本研究还为未来的氦气分析沿Denali断层系统，其他区域结构，其他区域结构以及负责Alaska地理资源负责的跨越层次的资源来评估NSF的智力传统的依从性，该元素的范围是依据的，该奖项反映了NSF的法定依据，该奖项反映了NSF的法定依据，构建了智力，该奖项反映了NSF的法定依据，该元素是跨国公司的范围，这是对未来跨越的区域结构的其他弹簧的框架。审查标准。