Development of a 4-D Model of Crustal Evolution in the Northern Rocky Mountains

落基山脉北部地壳演化 4 维模型的开发

• 批准号: 0545751
• 负责人: Paul Mueller
• 金额: $ 21.65万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0545751&HistoricalAwards=false
• 关键词: Development; Model; Crustal; Evolution; Northern

0545751MuellerIn order to optimize current and future deployment of EarthScope (ES) resources in the northern Rocky Mountains/Great Plains, a group of earth scientists from the University of Florida, Montana State University, and the U.S. Geological Survey are conducting research directed toward development of an integrated temporal and spatial (i.e., 4-D) framework for crustal evolution in this region. In particular, this region contains one of the most enigmatic segments of continental crust in North America, the Great Falls tectonic zone (GFTZ). This long-lived crustal structure has the most temporally extensive rock record in North America (ages to 4 billion years) and has had a major impact on the geologic history of this region, including younger episodes of faulting and seismicity, distribution of magmatism and ore deposits, and the creation of resource-rich sedimentary basins. For example, the intersection of the GFTZ and Trans-Hudson orogen, which developed ~ 1.8 billion years ago, is now the site of a major petroleum resource province, the Williston basin. Similarly, Phanerozoic structural reactivation, magmatism, seismicity, and mineralization in the northern Rocky Mountains is concentrated in the GFTZ, which leads to additional possibilities of how ancient structures and events may control modern earth processes and the distribution of resources.The research group is applying modern geochronologic (ion probe U-Pb), thermochronologic (multi-and single grain 40Ar-39Ar), and geochemical (major and trace elements) techniques to samples from outcrops, deep test wells, and xenoliths (pieces of the mantle and lower crust brought to the surface via volcanic eruptions). These results will be critical for both optimizing the deployment of ES resources and ultimately developing an integrated 4-D framework for the northern Rocky Mountain/northern Great Plains portion of North America. This 4-D framework is essential to: 1) unraveling one of the most intriguing episodes of continent formation in the geologic record, the formation of Laurentian North America; 2) understanding how the amalgamating collisional events were recorded in the crust and mantle; and 3) to what extent these ancient events affected subsequent crustal and lithospheric evolution in the northern Rocky Mountains/Great Plains. The research team is utilizing facilities from all three organizations (University of Florida, Montana State University, and the U.S. Geological Survey). Student participation at the graduate and undergraduate level is providing critical workforce training in geologic and analytical skills. The results of this research will be integrated into the evolving Montana GIS/DEM geologic map base being developed at Montana State University. All of the geochemical and geochronologic data will be numerically and spatially displayed in an interactive web format and accessible to geoscientists, educators, and the general public. Results will also be disseminated via meeting presentations and peer reviewed journals.

为了优化落基山脉/大平原北部的地球范围（ES）资源的当前和未来部署，来自佛罗里达大学、蒙大拿州立大学和美国地质调查局的一组地球科学家正在进行研究，旨在开发该地区地壳演化的综合时空（即4-D）框架。特别是，这个地区包含了北美大陆地壳中最神秘的部分之一，大瀑布构造带（GFTZ）。这种长寿的地壳结构在北美拥有时间最广泛的岩石记录（年龄到40亿年），并对该地区的地质历史产生了重大影响，包括年轻的断层和地震活动，岩浆活动和矿床的分布，以及资源丰富的沉积盆地的形成。例如，18亿年前形成的GFTZ和跨哈德逊造山带的交汇处，现在是一个主要的石油资源省威利斯顿盆地的所在地。同样，北落基山脉的显生宙构造活化、岩浆活动、地震活动和矿化活动也集中在GFTZ，这为古代构造和事件如何控制现代地球过程和资源分布提供了额外的可能性。该研究小组正在应用现代地质年代学（离子探针U-Pb）、热年代学（多粒和单粒40Ar-39Ar）和地球化学（主要元素和微量元素）技术，对露头、深测试井和捕虏体（火山喷发带来的地幔和下地壳碎片）的样品进行分析。这些结果对于优化ES资源的部署以及最终为北美北部落基山脉/北部大平原地区开发一个集成的4-D框架至关重要。这个4-D框架对于：1)揭开地质记录中最有趣的大陆形成事件之一——劳伦森北美大陆的形成——至关重要；2)了解合并碰撞事件如何记录在地壳和地幔中；3)这些古代事件在多大程度上影响了北落基山脉/大平原随后的地壳和岩石圈演化。研究小组正在利用所有三个机构（佛罗里达大学、蒙大拿州立大学和美国地质调查局）的设施。研究生和本科生的参与为地质和分析技能提供了关键的劳动力培训。这项研究的结果将被整合到蒙大拿州立大学正在开发的蒙大拿州GIS/DEM地质图库中。所有的地球化学和地质年代学数据将以数字和空间形式以交互式网络格式显示，地球科学家、教育工作者和公众都可以访问。研究结果也将通过会议报告和同行评议的期刊传播。