CAREER: Investigating the tectono-magmatic response to a transitioning plate boundary: a case study of the California Borderlands

职业：研究板块过渡边界的构造岩浆响应：加州边境地区的案例研究

• 批准号: 2338594
• 负责人: Andrea Balbas
• 金额: $ 99.88万
• 依托单位: California State University-Long Beach Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-07-01 至 2029-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338594&HistoricalAwards=false
• 关键词: CAREER; Investigating; tectono; magmatic; response

The California Borderlands is a submerged region directly west of Southern California and Baja Mexico. The region is unusual for its multiple basins (500-200 m deep) and ridges (some reach the surface and form the Channel Islands). It has experienced faulting, rotation, and volcanism over the past 30 million years while the approximate 1200 km tectonic boundary along the western limit of the North American tectonic plate transitioned from a subduction to a strike-slip orientation. It is not well understood why significant faulting, rotation, volcanism, and the formation of a new triple junction are localized to the region off southern California and northern Baja. This project seeks to understand what caused the California Borderlands volcanism and how it is related to a change from subduction to strike-slip. Broader impacts include research opportunities for multiple graduate and undergraduate students, a long-term intensive mentoring program for students recruited from underrepresented groups, support for a URM early-career researcher, collaborations with world-class analytical facilities, and outreach to K-12 schools.The goals of the project are to (1) investigate volcanic and tectonic processes not readily explained by standard plate boundary or hotspot dynamics. (2) Mentor and train a diverse pool of California State University Long Beach undergraduate and graduate students in ocean and geosciences. (3) Inspire and motivate a new generation of STEM professionals in the K-12 Norwalk School District. The PI proposes to define the timing and geochemical character of volcanic activity associated with processes uniquely recorded in the Borderland area off the coast of southern California that include the subduction of spreading centers and the transitioning from a subduction to transform boundary. While the unique geology of this submerged region records these rarely observed events, the limited temporal and geochemical constraints currently available lack coverage required to characterize these complex tectonic events via their resulting volcanic feedbacks. Here the PI presents a new regional tectonic model based on modern kinematics that indicate the Borderland region would have been affected by ridge-trench interaction at 30 Ma and 18 Ma. This proposal seeks to analyze previously retrieved seafloor volcanic samples to test the predictive consequences of the new tectonic model. This project will make use of these and other valuable samples from this area to answer transformative questions about the volcanic response prior to, during and after a plate boundary transition. The project will also train undergraduate student scientists from California State University Long Beach. The scientific work is ideal for supporting multiple undergraduate and graduate researchers because it scales from observations and detailed characterization of igneous rocks to more advanced procedures of chemical analyses. The program is designed to increase retention through the implementation of a longer term (one and half years as compared to a typical summer research experience) intensive mentorship program utilizing the cohort model. The proposed research and education activities are synergetic because they will (1) use the entirety of the proposed research as both undergraduate and graduate research projects (2) recruit graduate students from the undergraduate research program (3) incorporate weekly lab meetings to discuss research progress while also building a support network and providing mentorship. The undergraduate researchers supported by the PI will visit several local K-12 schools as community scientists to engage students and serve as role models striving for STEM careers.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.

加州边境是南加州和下墨西哥以西的一个水下地区。该地区因其多个盆地（500-200 米深）和山脊（其中一些到达地表并形成海峡群岛）而与众不同。在过去的3000万年里，它经历了断层、旋转和火山活动，而沿北美板块西界约1200公里的构造边界从俯冲方向转变为走滑方向。目前尚不清楚为什么显着的断层、旋转、火山活动和新三重交界点的形成都集中在南加州和北巴哈附近的地区。该项目旨在了解加州边境火山活动的原因以及它与从俯冲到走滑的变化之间的关系。更广泛的影响包括为多名研究生和本科生提供研究机会、为从代表性不足群体中招募的学生提供长期强化指导计划、对 URM 早期职业研究员的支持、与世界一流的分析设施的合作以及对 K-12 学校的推广该项目的目标是 (1) 研究标准板块边界或热点动力学无法轻易解释的火山和构造过程。 (2) 指导和培训加州州立大学长滩分校海洋和地球科学领域的多元化本科生和研究生。 (3) 激励和激励 K-12 诺沃克学区的新一代 STEM 专业人士。 PI 建议定义与南加州海岸边境地区独特记录的过程相关的火山活动的时间和地球化学特征，其中包括扩散中心的俯冲以及从俯冲到转换边界的过渡。 虽然这个淹没区域的独特地质记录了这些罕见的事件，但目前可用的有限时间和地球化学约束缺乏通过其产生的火山反馈来表征这些复杂构造事件所需的覆盖范围。在这里，PI 提出了一个基于现代运动学的新区域构造模型，该模型表明边境地区将在 30 Ma 和 18 Ma 时受到山脊-海沟相互作用的影响。该提案旨在分析先前回收的海底火山样本，以测试新构造模型的预测结果。该项目将利用该地区的这些和其他有价值的样本来回答有关板块边界转变之前、期间和之后火山响应的变革性问题。该项目还将培训加州州立大学长滩分校的本科生科学家。这项科学研究工作非常适合支持多名本科生和研究生研究人员，因为它的范围从火成岩的观察和详细表征到更先进的化学分析程序。该计划旨在通过利用队列模型实施长期（与典型的夏季研究经验相比为一年半）强化指导计划来提高保留率。拟议的研究和教育活动是协同的，因为它们将（1）将整个拟议研究用作本科生和研究生研究项目（2）从本科生研究计划中招收研究生（3）每周举行实验室会议来讨论研究进展同时还建立支持网络并提供指导。 PI 支持的本科生研究人员将作为社区科学家访问当地的几所 K-12 学校，吸引学生并成为努力 STEM 职业的榜样。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力评估进行评估，认为值得支持。优点和更广泛的影响审查标准。