Collaborative Research: Moving mountains: timing and emplacement of the Marysvale gravity slide complex

火山区是动态环境，其特点是快速变化的景观和极端的危险潜力。该研究项目的重点是学习和了解火山区坍塌和大规模滑坡产生的过程。项目目标将通过以下方式实现：对犹他州西南部的古代Marysvale重力滑坡综合体进行地质测绘，该滑坡是世界上最大的此类结构之一，由三个单独的巨型滑坡组成;确定滑坡中所含岩石的年龄;模拟滑坡起始和侧向迁移至起始地点以南35公里以上的距离。该研究项目汇集了一个新的多机构，多学科的合作，并将为研究生和本科生提供支持。本研究期间收集的高分辨率三维地质数据将用于开发虚拟实地考察和实地营地测绘模块。这些模块将是交互式的，包含露头模型，地质图和样本，使学生和公众能够更多地了解火山灾害和大规模山体滑坡。这些单元还将服务于一项更广泛的使命，使地球科学能够为广泛的、多样化的人口所利用。美国犹他州西南部的Marysvale火山区在渐新世晚期至中新世期间经历了三次连续的特大规模崩塌事件，统称为Marysvale重力滑动复合体（MGSC）。地层序列，运动学指标，基础结构，普遍的碎片，和pseudotachylyte集体表明，这些幻灯片中的每一个发生在个别事件的高速侵位。这些山体滑坡的悬而未决的问题包括：（1）火山区的条件使其容易发生大规模崩塌，以及（2）允许由此产生的巨大滑坡在重力的驱动下高速行进数十公里的因素。MGSC提供了一个极好的机会来解决这些问题，因为滑块的内部结构和基底滑动面的特殊暴露。通过一个多学科的方法相结合的地质测绘，地质年代学，岩石力学分析和数值模拟，我们将评估的时间相对于火山场和主要喷发事件的演变，滑动启动的作用，一个软基滑动启动，和热加压，损伤和剪切局部化滑动的流动性和减速的综合作用的滑动启动。地质测绘和实地工作，结合40 Ar/39 Ar和锆石U-Pb地质年代学，将提供对时间的限制，每个滑动的尺寸和连续性，以及基底滑动面的结构。岩石性质的实验室测量，结合基于现场的地质参数，将用于约束促进滑坡活动性和滑坡前稳定性条件的耦合过程的数值模型，代表了对大规模、长期滑坡模型的前所未有的地质约束水平。&科学。该奖项反映了NSF的法定使命，并已被认为是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的支持。

Volcanic fields are dynamic environments, characterized by rapidly evolving landscapes and extreme hazard potential. This research project is focused on learning and understanding the processes involved in collapse of volcanic fields and production of mega-scale landslides. The project objectives will be achieved by geologic mapping of the ancient Marysvale gravity slide complex in southwestern Utah, one of the largest such structures in the world that is made up of three individual mega-scale slides, determining the age of rocks contained in the slides, and modeling slide initiation and lateral transport to distances over 35 km to the south of their initiation sites. This research project assembles a new multi-institution, multi-disciplinary collaboration and will provide support for graduate and undergraduate students. High-resolution 3D geologic data collected during this study will be used to develop virtual field trips and field camp mapping modules. These modules will be interactive and contain outcrop models, geologic maps, and samples that will enable students and the public to learn more about volcanic hazards and mega-scale landslides. The modules will also serve a broader mission to make the Earth Sciences accessible to a broad, diverse population. During the late Oligocene to Miocene, the Marysvale volcanic field of southwestern Utah, USA, experienced three consecutive mega-scale catastrophic collapse events, collectively called the Marysvale gravity slide complex (MGSC). The stratigraphic succession, kinematic indicators, basal structures, pervasive fragmentation, and pseudotachylyte collectively suggest that emplacement of each of these slides occurred at high velocity during individual events. Outstanding questions for these landslides include (1) the conditions of the volcanic field that made it susceptible to mega-scale collapse, and (2) the factors which allowed the resulting gigantic slides to travel tens of kilometers at high velocity, driven by gravity. The MGSC provides an excellent opportunity to address these questions due to the exceptional exposure of the internal structure and basal slide planes of the slide blocks. Through a multidisciplinary approach combining geologic mapping, geochronology, rock mechanics analyses, and numerical modeling, we will evaluate the timing of slide initiation with respect to evolution of the volcanic field and major eruptive events, the role of a frictionally weak substrate on slide initiation, and the combined roles of thermal pressurization, damage, and shear localization on slide mobility and deceleration. Geological mapping and field work, combined with 40Ar/39Ar and zircon U-Pb geochronology, will provide constraints on timing, the dimensions and continuity of each slide, and the structure of the basal sliding surface. Laboratory measurements of rock properties, combined with field-based geologic parameters, will be used to constrain numerical models of both the coupled processes facilitating slide mobility and the conditions of pre-slide stability, representing an unprecedented level of geologic constraint on models of massive-scale, long runout landslides.This project is jointly funded by the Tectonics program and the Petrology & Geochemistry program in the division of Earth Sciences.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.