CAREER: Deciphering the mechanisms of forearc basin formation by engaging undergraduate and middle school students in field and analytical geoscience research

由火山链组成的山带，被称为岩浆弧，形成于板块俯冲到大陆或岛弧之下的构造汇聚边缘。弧前盆地在岩浆弧的辐合边缘向海方向发育，并将沉积物圈闭在深槽中。这些盆地可以存在数千万年到数亿年，是过去地球环境、过程、气候制度和生命的长期记录。它们还拥有石油和天然气等自然资源。本研究的目的是通过研究盆地下的岩石类型与盆地内保存的沉积岩之间的关系来确定弧前盆地的起源。该项目的研究和教育部分侧重于通过与蒙大拿州农村社区代表性不足的本科生和中学女生的持续接触，增加地球科学的多样性和可及性。学生将参与研究设计、实地和实验室工作以及国家会议。学生们还将帮助领导一个针对中学女生的STEM研讨会，重点关注美国西部和西藏的岩石和矿物。该项目将解决地球演化中的关键问题，并为传统上很少参与地球科学的学生提供机会。由于岩石记录保存不完整或后期变形叠加了原始构造和地层关系，弧前盆地的形成机制尚不清楚。本研究将验证一个假设，即弧前地区下伏基底的伸展提供了一种捕集沉积物和引发盆地下沉的机制，这是弧前盆地形成的前兆。该假设将通过应用年代学和地球化学方法来描述基底形成的构造背景、基底-弧前发育的时间和速率以及随后的地质历史来验证。该研究将结合野外填图和沉积学、砂岩岩石学、生物地层学、地质年代学、古地磁学和低温热年代学。野外地区包括加利福尼亚的大峡谷前弧和西藏的日喀则前弧。在相似但不完全相同的构造背景下，每个地区都保留了基底和盆地地层之间的基本关系。通过建立蒙大拿州立大学沉积本科研究项目（MSU-SUR），教育计划与研究活动相结合，该项目旨在通过与美国原住民和第一代大学生的持续接触来扩大地球科学社区。密歇根州立大学南苏尔分校的学生将通过参与文献综述和实地规划，以及收集和评估数据和传播结果，直接为研究做出贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mountain belts that incorporate chains of volcanoes, called magmatic arcs, develop at tectonic convergent margins where an oceanic plate is subducting beneath a continent or island arc. Forearc basins develop oceanward of the magmatic arc of a convergent margin and trap sediment in deep troughs. These basins can exist for tens to hundreds of millions of years, serving as a long-term record of past Earth environments, processes, climate regimes, and life. They also host natural resources such as oil and gas. The goal of this research is to determine the origin of forearc basins by investigating the relationship between the types of rocks that underlie the basin and the sedimentary rocks preserved within the basin. The research and education components of this project focus on increasing diversity in, and accessibility to, the geosciences through sustained engagement with underrepresented undergraduate students and middle school girls from rural communities in Montana. Students will participate in research design, field and laboratory work, and national conferences. Students also will help lead a STEM workshop for middle school girls focused on rocks and minerals from the western U.S. and Tibet. The project will resolve critical questions in the evolution of Earth and offer opportunities to students who traditionally have limited participation in the geosciences.The mechanisms of forearc basin formation are not well understood because of poor preservation in the rock record or overprinting of primary tectonic and stratigraphic relationships by subsequent deformation. This research will test the hypothesis that extension of the underlying basement in a forearc region provides a mechanism to trap sediment and initiate basin subsidence as a precursor to forearc basin formation. The hypothesis will be tested by applying chronologic and geochemical methods to describe the tectonic setting of basement formation, timing and rates of basement-forearc development, and subsequent geologic history. The research will combine field mapping and sedimentology with sandstone petrography, biostratigraphy, geochronology, paleomagnetism, and low-temperature thermochronology. Field areas include the Great Valley forearc, California and the Xigaze forearc, Tibet. Each field area preserves primary relationships between basement and basin stratigraphy in similar, but not identical tectonic settings. The education plan integrates with the research activities by establishing the Montana State University Sedimentary Undergraduate Research program (MSU-SUR), which seeks to broaden the Earth Science community through sustained engagement with Native American and first-generation college students. Students in the MSU-SUR program will contribute directly to the research by participating in literature review and field planning, along with collecting and evaluating data and disseminating results.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.