Collaborative Research: New Constraints on the Geodynamics of the Lake Bonneville Basin

这个项目的意义部分是基于这种类型的机会在地球动力学研究中的稀有性。博纳维尔湖是更新世晚期地球上最大的雨积湖之一，拥有最著名的湖平面历史之一，拥有已知年代的多条海岸线，现在拥有与任何规模相当的雨积湖盆地最好的地形数据集。这些因素的汇合，以及在模拟和分析方面的进展，将有助于更好地了解均衡反弹和伴随的地壳变形的过程和速率。这项研究将为在其他区域和其他大陆的湖泊盆地进行地球动力学研究提供一个模板。除了对Bonneville盆地的地球动力学有了新的认识，这将被地球物理学家和其他人用来更好地约束粘度模型和理解地震周期，这项研究的结果对地质年代学等其他学科也有影响。这项工作的结果还可以通过更好地约束高热流异常的尺寸来帮助地热能勘探，高热流异常可能由与负荷历史不一致的超高海岸线区域表示。该项目还将导致研究生的跨学科培训，并通过大盆地古环境数据库网站（www.dri.edu/gbped）向广大受众突出和传播。除了将研究成果的新出版物添加到该数据库之外，该项目还将开发一个在线教育模块，重点介绍Bonneville盆地的环境和地球动力学历史。这个模块将是一个更大的努力的一部分，教育感兴趣的观众在大盆地的第四纪历史的各个方面。自1890年引入粘弹性基底上的弹性板块均衡模型以来，博纳维尔湖盆地已成为地球动力学研究的首要例子之一。从那时起，该盆地一直是许多研究的主题，这些研究详细阐述了均衡反弹的时间、幅度和过程，以及地壳和上地幔对博纳维尔湖施加的巨大负荷的反应。该项目的目标是采用更高密度的海岸线高程测量，更精细的加载历史，对反弹信号的地理信息系统空间分析，以及模拟地球均衡响应的全三维有限元模型。自从上次关于盆地回弹的主要出版物发表以来，在湖泊水位年表（加载历史）、建模复杂性、三维分析、地形数据以及定义多个离散海岸线记录的回弹几何形状的能力方面取得了重大进展。这些改进的结合将导致一个更好的三维地球模型，记录岩石圈强度和粘度结构的横向变化。这项工作的地质年代学结果可能对海岸线发育速度提供限制，也可能导致对宇宙形成表面暴露定年的校准产量进行修订。

The significance of this project is based, in part, on the rarity of this type of opportunity in geodynamic research. Lake Bonneville was one of the largest pluvial lakes on the planet during the late Pleistocene, has one of the best known lake-level histories, possesses multiple shorelines of known ages, and is now covered by the best topographic data set for any pluvial lake basin of comparable size. The convergence of these factors, as well as advances in modeling and analysis, will facilitate greater understanding of the processes and rates of isostatic rebound and accompanying crustal deformation. This study will provide a template for what is possible for geodynamic studies in lacustrine basins located in other regions and on other continents. In addition to developing new insights on the geodynamics of the Bonneville basin that will be used by geophysicists and others to better constrain viscosity models and understand the earthquake cycle, the results of this research have implications for other disciplines such as geochronology. Results from this work may also assist in geothermal energy exploration by better constraining the dimensions of high heat flow anomalies, which may be expressed by regions of super-elevated shorelines not consistent with their loading history. This project will also result in the interdisciplinary training of graduate students and be highlighted and disseminated to a broad audience through the Great Basin Paleoenvironmental Database website (www.dri.edu/gbped). In addition to adding to this database with new publications resulting from the research, the project will develop an online educational module highlighting the Bonneville basin's well documented environmental and geodynamic history. This module will be part of a larger effort to educate interested viewers on various aspects of the Quaternary history of the Great Basin.The Lake Bonneville basin has become one of the premier examples of geodynamic research since the isostasy model of an elastic plate overlying a visco-elastic substrate was introduced in 1890. Since that time, the basin has been the subject of numerous studies elaborating on the timing, magnitude, and processes of isostatic rebound and the response of the crust and upper mantle to the enormous loads imposed by Lake Bonneville. The goal of this project is to employ much higher density shoreline elevation measurements, a more refined loading history, geographic information system spatial analysis of the rebound signal, and a fully three-dimensional finite-element model for simulating the isostatic response of the Earth. Since the last major publication on the rebound of the basin, significant improvements have been made to the lake-level chronology (loading history), modeling sophistication, three-dimensional analysis, topographic data, and the ability to define the geometry of rebound recorded by multiple, discrete shorelines. The combination of these improvements will lead to a much better constrained three-dimensional Earth model documenting lateral variations in lithospheric strength and viscosity structure. Geochronology results from the work may provide constraints on rates of shoreline development and also may lead to revision of calibrated production rates for cosmogenic surface exposure dating.