Collaborative Research: Reconstructing the missing record of late Proterozoic tectonism along the western margin of Laurentia using deep-time thermochronology

合作研究：利用深时热年代学重建劳伦大陆西缘晚元古代构造运动的缺失记录

• 批准号: 2140481
• 负责人: Stephen Cox
• 金额: $ 23.61万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2140481&HistoricalAwards=false
• 关键词: Collaborative; Research; Reconstructing; missing; record

Studies of sedimentary rocks provide geoscientists a record of Earth’s history, including the appearance and evolution of life, the growth and demise of mountains, and how the climate has changed. However, natural processes driven by plate tectonics mean that this sedimentary record is inherently incomplete. At different times during Earth’s history, some regions experienced sediment deposition, which buries and therefore heats up rocks, while other regions experienced erosion, which both removes portions of the rock record and cools off the rocks that persist by bringing them closer to Earth’s surface. This study will use the geochemical signatures of rock heating and cooling that occurs during deposition and erosion to understand the geologic histories of areas where no sedimentary rocks remain. Specifically, the study will investigate the ancient record of supercontinent breakup, a process that drives changes in sea level, global climate, and topography. This project will provide support for three early-career researchers at different universities, including two women, and build new relationships among the collaborating research groups. Three graduate and nine undergraduate students from different universities will be engaged in collaborative, hypothesis-driven research and learn a range of field, laboratory, and science communication methods. The researchers will also collaborate with the Idaho Museum of Natural History to create a mobile museum exhibit that will highlight the ancient history of the charismatic mountain ranges in the study area and visit museums that serve rural communities in the Rocky Mountains.Unconformities, which are abundant in the rock record, are traditionally viewed as unfillable gaps in the rock record of Earth’s history. However, the thermal imprint of sedimentary cover on the basement rocks that underlie many unconformities provides a rich archive of the otherwise inaccessible parts of a continent’s tectonic history. This record is now accessible due to recent conceptual and analytical advances in low-temperature thermochronology. The primary objective of this study is to contribute to these advances by targeting a critical gap in knowledge about Laurentian tectonics, the breakup of supercontinent Rodinia, while establishing an approach to deep-time thermochronology that can document Precambrian tectonic activity in regions that also experienced significant Phanerozoic mountain building. This study will sample along a 700-kilometer-long segment of western Laurentia’s rifted margin, targeting basement rocks directly below the Great Unconformity and using four chronometers to produce holistic tectonothermal histories to fill a billion-year gap in the rock record. This study will demonstrate how deep time thermochronology can provide a new perspective on the geometry and tectonic evolution of western Laurentia’s rifted margin, where much or all of the sedimentary record of Neoproterozoic tectonism is missing. This capability will be tested by (1) establishing a clear link between extant Neoproterozoic sedimentary rocks and Neoproterozoic tectonothermal events in the Uinta Mountains, (2) documenting the Proterozoic thermal histories of basement blocks with no overlying Neoproterozoic strata in the Teton Range and southwestern Montana, and (3) quantifying intra-mountain range variability of Proterozoic thermal histories to evaluate the sampling spatial resolution necessary for extracting meaningful tectonic information from the deep-time thermochronologic record.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.

对沉积岩的研究为地球科学家提供了地球历史的记录，包括生命的外观和演变，山的成长和灭亡以及气候如何改变。但是，由板块构造驱动的自然过程意味着这种沉积记录本质上是不完整的。在地球历史上的不同时间，一些地区经历了沉积物沉积，因此埋葬并加热岩石，而其他地区则经历了侵蚀，这两者都消除了部分岩石记录，并通过使它们更接近地球表面来消除岩石。这项研究将使用在沉积和侵蚀期间发生的岩石加热和冷却的地球化学特征，以了解不存在沉积岩石的地区的地质历史。具体而言，该研究将研究超大型分手的古老记录，这一过程驱动了海平面，全球气候和地形的变化。该项目将为包括两名女性在内的不同大学的三名早期研究人员提供支持，并在协作研究小组之间建立新的关系。来自不同大学的三名毕业生和九名本科生将参与合作，假设驱动的研究，并学习一系列领域，实验室和科学传播方法。研究人员还将与爱达荷州自然历史博物馆合作，创建一个移动博物馆展览，该展览将凸显研究区关键山脉的古老历史，并参观为落基山脉的农村社区提供服务的博物馆。岩石唱片中富裕的岩石记录中富裕的岩石唱片中，传统上被视为地球历史上的岩石唱片中的无能为力。但是，基于许多不整合的地下岩石上沉积覆盖的热烙印为非整合性的构造提供了丰富的档案。由于低温热量学的最新概念和分析进步，现在可以访问该记录。这项研究的主要目的是通过针对有关劳伦斯构造学的知识的临界差距，即超大陆的罗迪尼亚的破裂，同时建立了一种可以记录在地区的前寒武纪构造活动的方法，从而为这些进步做出了贡献，这些方法也可以记录在该地区也经历了大量的phanerorzoic山区建筑。这项研究将沿西部劳伦（Laurentia）的裂谷边缘的700公里长的段进行采样，将地下室岩石的瞄准位于巨大的不整合度下方，并使用四个天文钟产生整体的构造构造历史记录，以填补岩石记录中数十亿年的差距。这项研究将证明热量的深度热量学如何为西部劳伦蒂亚裂痕边缘的几何形状和构造演变提供新的观点，在那里缺少新元古代构造的大部分或全部沉积记录。 This capability will be tested by (1) establishing a clear link between extensive Neoproterozoic sedimentary rocks and Neoproterozoic tectonothermal events in the Uinta Mountains, (2) documenting the Proterozoic thermal histories of basement blocks with no overlying Neoproterozoic strata in the Teton Range and southwestern Montana, and (3) quantifying intra-mountain range variability properokoic热热历史以评估从深度热力学记录中提取有意义的构造信息所需的采样空间分辨率。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛的影响审查标准来评估通过评估而被认为是珍贵的。