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

火山田是动态的环境，其特点是地貌迅速演变和极端的潜在危险。这一研究项目的重点是学习和理解火山场坍塌和大规模滑坡产生的过程。项目目标将通过对犹他州西南部的古代马里斯维尔重力滑坡体进行地质测绘来实现，该滑坡体是世界上最大的此类结构之一，由三个单独的超大型滑体组成，确定滑体中所含岩石的年龄，并模拟滑体的启动和横向运输到其起始点以南超过35公里的距离。这项研究项目集合了一个新的多机构、多学科的合作，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野外旅行和野外营地测绘模块。这些模块将是交互式的，包含露头模型、地质图和样本，使学生和公众能够了解更多关于火山灾害和大规模山体滑坡的知识。这些模块还将服务于更广泛的任务，使广泛、多样化的人口能够接触到地球科学。在渐新世晚期至中新世，美国犹他州西南部的马里斯维尔火山田经历了三次连续的大规模灾难性坍塌事件，统称为马里斯维尔重力滑动杂岩(MGSC)。地层序列、运动学标志、基底构造、普遍的碎屑和假玄武岩共同表明，这些滑坡在个别事件期间以高速侵位的方式就位。这些滑坡的突出问题包括(1)火山场的条件使其容易发生大规模坍塌，以及(2)在重力的驱动下，导致巨大滑坡以高速移动数十公里的因素。由于滑块内部结构和基本滑动面的特殊暴露，MGSC提供了解决这些问题的绝佳机会。通过结合地质填图、地质年代学、岩石力学分析和数值模拟的多学科方法，我们将评估关于火山场和主要喷发事件的演化的滑坡起始时间，摩擦弱基底对滑坡起始的作用，以及热压、损伤和剪切局部化对滑坡移动性和减速的综合作用。地质测绘和野外工作，结合40Ar/39Ar和锆石U-Pb年代学，将提供对时间、每个滑动的尺寸和连续性以及基面滑动面结构的限制。实验室对岩石性质的测量，结合基于现场的地质参数，将被用来约束促进滑坡移动的耦合过程的数值模型和滑坡前的稳定性条件，这代表了对大规模、长时间滑坡模型的前所未有的地质约束。该项目由地球科学部的构造计划和岩石学与地球化学计划联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.