Collaborative Research: RUI: An undergraduate cohort thermochronology research and mentorship experience investigating the thermo-tectonic record of the northern Klamath Mountains

合作研究：RUI：本科生群体热年代学研究和指导经验，调查克拉马斯山脉北部的热构造记录

• 批准号: 2242862
• 负责人: Francis Sousa
• 金额: $ 17.26万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2242862&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; undergraduate; cohort

The geologic history of mountain building events is chronicled in the rock record, especially along former tectonic plate boundaries. Approximately 56 million years ago, a large basaltic oceanic plateau, the Siletzia-Crescent terrane, erupted off what is now the coast of the Pacific Northwest. A few million years after eruption, it collided with North America, and is proposed to have caused i) tectonic plate rotations, ii) mountain building and major regional-scale faulting, and iii) the subduction zone plate boundary to jump westward, establishing the modern Cascadia subduction zone. Today, the southern edge of Siletzia-Crescent terrane collision is preserved as a sliver of basaltic rock thrust on older sedimentary rocks in southern Oregon. Few syn-collisional sedimentary rocks survive from the time of Siletzia collision, rendering direct investigation of the effect of the collision challenging. To overcome this challenge, the investigators will target specific minerals in older, crystalline rocks from the northern Klamath Mountains, located south of the collision suture. Using this approach, the research team will reconstruct the burial, thickening, uplift, and erosion history of the region in response to collision. Geochemical analysis of these mineral chronometers is an application commonly used to address large scale tectonics questions, however, the advanced technique is typically available only to scientists at large, primarily research-oriented institutions. In this project, the principal investigators will center a group of undergraduate researchers at Cal Poly Humboldt and Oregon State University, locations that straddle the geologic region of interest, to reconstruct the tectonic history of the southern Siletzia-North American collisional zone, by applying multiple mineral chronometers, in a collaborative, academic-year, cohort-based undergraduate research experience. Siletzia formation and subsequent accretion marks a major shift in western U.S. subduction tectonics. The timing of Siletzia collision is coincident with the shut off of Farallon slab subduction and predates the formation of the modern Cascadia subduction zone and arc. The Siletzia terrane comprises the basement rock over a 600 km stretch of western North America from Roseburg, OR to Vancouver Island. However, the spatial and thermal impact of Siletzia accretion on the North American continent is not well understood, largely due to a missing and overprinted geologic and thermal record. The investigators will center undergraduate student research contributions through a novel, year-long, comprehensive cohort experience. The research team will apply multi-method mid- and low-temperature thermochronometry to northern Klamath Mountain samples to assess the continent’s response prior to, during, and following Siletzia accretion. Results will address a major knowledge gap in regional evolution of the Cascadia Subduction Zone, have implications for the thermal and spatial magnitude and rate of exhumation, burial, and deformation driven by accretion tectonics on overriding continental plates, address challenges resolving tectonic and landscape evolution events that are missing from the rock record using multi-method thermochronometry, and engage undergraduate students as primary research contributors guided by three Principal Investigators with overlapping expertise.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.

岩石记录记录了造山事件的地质历史，特别是在大约 5600 万年前，一个巨大的玄武岩海洋高原（Siletzia-Crescent 地体）在现在的太平洋西北海岸爆发。喷发后几百万年，它与北美相撞，并被认为引起了 i) 构造板块旋转，ii) 造山和主要区域规模。断层作用，以及 iii) 俯冲带板块边界向西跳跃，建立了现代卡斯卡迪亚俯冲带。 如今，西莱齐亚-新月地体碰撞的南缘被保留为俄勒冈州南部较古老沉积岩上的一小片玄武岩。同碰撞沉积岩从 Siletzia 碰撞中幸存下来，这使得直接研究碰撞的影响具有挑战性，为了克服这一挑战，研究人员将针对较古老的结晶岩石中的特定矿物。位于碰撞缝合线以南的克拉马斯山脉北部，研究小组将利用这种方法重建该地区因碰撞而发生的埋藏、加厚、隆起和侵蚀历史，这些矿物计时器是常用的应用程序。然而，为了解决大规模的构造问题，这种先进技术通常只有大型研究机构的科学家才能使用，在这个项目中，主要研究人员将以加州州立大学洪堡分校和俄勒冈州立大学的本科生研究人员为中心。地点横跨感兴趣的地质区域，通过应用多个矿物计时仪，重建 Siletzia 南部-北美碰撞带的构造历史，在一个为期学术年的、基于队列的本科生研究经验中，Siletzia 的形成和随后的增生标志着一个新的研究。美国西部俯冲构造的重大转变 西莱齐亚碰撞的时间与法拉伦板片俯冲的结束同时发生，并且早于现代卡斯卡迪亚的形成。 Siletzia 地体由北美西部从俄勒冈州罗斯堡到温哥华岛绵延 600 公里的基底岩石组成。然而，Siletzia 增生对北美大陆的空间和热影响尚不清楚。由于地质和热记录的缺失和叠印，研究人员将通过为期一年的新颖、全面的队列经验来集中本科生的研究贡献。对克拉马斯山北部样本进行热测时，以评估大陆在 Siletzia 增生之前、期间和之后的响应，结果将解决卡斯卡迪亚俯冲带区域演化的主要知识差距，对热和空间规模以及折返速度产生影响。由覆盖大陆板块上的增生构造驱动的埋藏和变形，解决了使用多种方法解决岩石记录中缺失的构造和景观演化事件的挑战热测时法，并让本科生作为主要研究贡献者，由三位具有重叠专业知识的首席研究员指导。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。