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: 2413966
• 负责人: Tomas Capaldi
• 金额: $ 36.62万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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: 2023-10-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2413966&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两座城市多次被安第斯山脉造山运动产生的地质结构所引起的大规模地震破坏或夷为平地。由于活跃的地震活动发生在沿着断层，这些断层可以表现在或隐藏在地球表面之下，这些神秘的结构的性质和历史仍然存在争议。已经提出了几个相互竞争的地质模型，将深度的地震活动与地表的断层和山脉联系起来。该项目将通过实地工作来解决这些争论，绘制断层关系图，测量相关的沉积盆地沉积物，记录安第斯山脉活跃增长的隆起和侵蚀历史。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。在阿根廷科学家合作的帮助下，新的长期断层变形现场和分析记录将与地球物理观测和数十年的地震数据相结合。这将导致更好地了解构造力如何在深部和表层地质结构之间分配，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口和基础设施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，以支持多样化和历史上代表性不足的高中，本科和博士生参与地球科学研究和教育。这将涉及指导参与机构的本科生和研究生，并创建一个基于地方的教育虚拟实地考察，通过美国西部和阿根廷的实地考察。构造应力与平板俯冲驱动变形800公里内横跨破碎的前陆阿根廷中西部。不断缩短容纳在重叠的薄皮和基底涉及的结构省份，使这个破碎的前陆地区成为地球上地震最活跃的地方之一。然而，在薄皮的中央前心地区、Sierras Pampeanas基底隆起或东部前心地区构造域神秘的逆冲前缘之间的结构或运动学联系上没有共识。主要研究人员的目标是通过以下方式解决结构之间的时间和运动学关系：（1）确定东前心冲断层前缘变形的时间和幅度;（2）询问剥露冷却和沉降的空间模式如何与基于该地区各种结构几何形状和运动学的预测相一致。他们的研究计划将整合地质和构造绘图、盆地分析、地质和热年代学以及弯曲热运动学建模，以区分假设的构造模型。评估阿根廷地震活跃的结构域之间的时空关系将为地下结构几何形状模型提供信息，缩短如何从地壳下层转移到地壳上层，以及锋面逆冲构造和前陆盆地沉积之间的长期相互作用。新的研究结果将量化在板块俯冲过程中俯冲板块和上覆板块之间增强的机械耦合的影响，这决定了造山作用的热构造演化和山区地带的地形生长和衰退。该奖项反映了NSF的法定使命，并被认为值得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来支持。