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

合作研究：邦纳维尔湖盆地地球动力学的新约束

• 批准号: 1349315
• 负责人: Charles Oviatt
• 金额: $ 8.7万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2019-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1349315&HistoricalAwards=false
• 关键词: Collaborative; Research; New; Constraints; Geodynamics

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.

这个项目的意义部分是基于地球动力学研究中这类机会的稀缺性。博纳维尔湖是地球上最大的雨积湖之一，在晚更新世，拥有最著名的湖平面历史之一，拥有多条已知时代的海岸线，现在被任何可比大小的雨湖盆地中最好的地形数据所覆盖。这些因素的汇聚，以及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。这项研究将为位于其他区域和其他大陆的湖泊盆地的地球动力学研究提供一个模板。除了对波纳维尔盆地的地球动力学提出新的见解，地球物理学家和其他人将利用这些见解来更好地约束粘性模型和了解地震周期，这项研究的结果还对地质年代学等其他学科有影响。这项工作的结果还可以通过更好地限制高热流异常的尺寸，从而有助于地热能勘探，高热流异常可能由与其加载历史不一致的超高海岸线区域来表示。该项目还将对研究生进行跨学科培训，并通过大盆地古环境数据库网站(www.dri.edu/gbed)突出显示并向广大受众传播。除了用这项研究产生的新出版物添加到这个数据库之外，该项目还将开发一个在线教育模块，突出波纳维尔盆地有充分记录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，目的是教育感兴趣的观众了解大盆地第四纪历史的各个方面。自1890年引入弹性板块覆盖在粘弹性底板上的均衡模型以来，博纳维尔湖盆地已经成为地球动力学研究的主要例子之一。自那时以来，该盆地一直是许多研究的主题，阐述了均衡反弹的时间、大小和过程，以及地壳和上地幔对博纳维尔湖施加的巨大负荷的响应。该项目的目标是采用密度更高的海岸线高程测量，更精确的加载历史，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。自从上一次关于盆地反弹的主要出版物发表以来，在湖泊水平年代学(加载历史)、建模的复杂性、三维分析、地形数据以及确定由多条离散海岸线记录的反弹几何图形的能力方面取得了重大改进。这些改进的结合将产生一个更好的受约束的三维地球模型，记录岩石圈强度和粘性结构的横向变化。这项工作的地质年代学结果可能对海岸线的发育速度提供限制，还可能导致修订宇宙成因地表暴露年代的校准生产率。