Collaborative Research: Resolving thin-skinned and basement-involved deformation within a seismically active broken foreland region, San Juan, Argentina

合作研究：解决阿根廷圣胡安地震活跃的破碎前陆地区的薄皮和基底变形问题

• 批准号: 2242878
• 负责人: Tomas Capaldi
• 金额: $ 36.62万
• 依托单位: University of Nevada Las Vegas
• 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 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2242878&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolving; thin; skinned

The cities of Mendoza and San Juan, Argentina, have been repeatedly damaged or leveled by large-magnitude earthquakes generated by geological structures associated with Andean mountain building. Because active seismicity occurs along faults that can be expressed at or hidden below Earth’s surface, the nature and history of these enigmatic structures remains debated. Several competing geologic models have been proposed that link the seismicity at depth with faults and mountain ranges expressed at Earth’s surface. This project will address these debates through fieldwork to map fault relationships and measurement of associated sedimentary basin deposits that record the uplift and erosion history of actively growing Andean ranges. A variety of geochronologic and low-temperature thermochronologic analytical techniques will be employed to determine the timing and magnitude of deformation across the geological structures. Results will be integrated using computational models to help resolve the debated geologic history for these Andean ranges. New field and analytical records of long-term fault deformation will be integrated with geophysical observations and decades of earthquake data with the help of collaborating Argentinian scientists. This will lead to a better understanding of how tectonic forces are partitioned among deep and surficial geologic structures and which faults may generate large magnitude earthquakes, information that is critical for assessments of Andean earthquake hazards with the potential to impact human populations and infrastructure. In addition to the scientific goals of the research, the award supports the development of infrastructure to support the engagement of diverse and historically underrepresented high school, undergraduate, and PhD-level students in geoscience research and education. This will involve mentoring undergraduate and graduate students at the participating institutions and creating a place-based educational virtual field trip through the western USA and field area in Argentina.Tectonic stresses associated with flat slab subduction have driven deformation 800 km inboard across the broken foreland of west-central Argentina. Ongoing shortening accommodated within the overlapping thin-skinned and basement-involved structural provinces makes this broken foreland region one of the most seismically active places on Earth. However, there is no consensus on the structural or kinematic links between the thin-skinned Central Precordillera, the Sierras Pampeanas basement uplifts, or the enigmatic thrust front of the Eastern Precordillera structural domain. The principal investigators aim to resolve the temporal and kinematic relationships among structures by (1) determining the timing and magnitude of deformation in the Eastern Precordillera thrust front and (2) interrogating how spatial patterns in exhumational cooling and subsidence coincide with predictions based on the various structural geometries and kinematics proposed for the region. Their research plan will integrate geologic and structural mapping, basin analysis, geo- and thermochronology, and flexural thermokinematic modeling to discriminate between hypothesized structural models. Evaluating spatial-temporal relationships among the seismically active, structural domains in Argentina will inform models of subsurface structural geometries, how shortening transfers from lower to upper crustal levels, and the long-term interactions between frontal thrust structures and foreland-basin sedimentation. New results will quantify the effects of enhanced mechanical coupling between the subducting and overriding plate during flat slab subduction, which dictates the thermo-tectonic evolution of orogenesis and topographic growth and decay of mountain belts.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.

阿根廷的门多萨和圣胡安市多次因与安第斯山脉建筑相关的地质结构引发的大地震而遭到破坏或夷为平地，因为活跃的地震活动沿着可以表现在地球表面或隐藏在地球表面以下的断层发生，自然。人们提出了几种相互竞争的地质模型，将深度地震活动与地球表面表达的断层和山脉联系起来。绘制断层关系和测量相关沉积盆地沉积物，记录活跃生长的安第斯山脉的隆起和侵蚀历史，将采用各种地质年代学和低温热年代学分析技术来确定地质结构变形的时间和幅度。将使用计算模型整合结果，以帮助解决这些安第斯山脉有争议的地质历史，并将借助地球物理观测和数十年的地震数据整合长期断层变形的新现场和分析记录。阿根廷科学家的合作将有助于更好地了解构造力如何在深层和地表地质结构之间划分，以及哪些断层可能产生大规模地震，这些信息对于评估可能影响人类的安第斯地震灾害至关重要。除了研究的科学目标外，该奖项还支持基础设施的发展，以支持多样化且历史上代表性不足的高中、本科生和博士生参与地球科学研究和教育。指导参与机构的本科生和研究生，并创建一个穿越美国西部和阿根廷野外地区的基于地点的教育虚拟实地考察。与平板俯冲相关的构造应力已导致中西部破碎前陆向内变形 800 公里阿根廷：重叠的薄皮和基底构造省内的持续缩短使得这个破碎的前陆地区成为地球上地震最活跃的地区之一。薄皮中央普雷迪勒拉、潘皮纳斯山脉基底隆起或东普雷迪勒拉构造域神秘的冲断锋之间的运动学联系主要研究人员旨在通过以下方式解决结构之间的时间和运动学关系：（1）确定时间和幅度。东部 Precordillera 逆冲锋面的变形；(2) 探讨折返冷却和沉降的空间模式如何与基于各种结构几何形状和他们的研究计划将整合地质和构造测绘、盆地分析、地质年代学和弯曲热运动学建模，以评估阿根廷地震活跃的构造区域之间的时空关系。为地下结构几何模型、从下地壳层到上地壳层的缩短过程以及锋面逆冲结构与前陆盆地沉积之间的长期相互作用提供信息。新的结果将量化其影响。平板俯冲过程中俯冲板块和上覆板块之间增强的机械耦合，决定了造山运动的热构造演化以及山地带的地形生长和衰变。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。