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: 2140482
• 负责人: Devon Orme
• 金额: $ 15.04万
• 依托单位: Montana State 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=2140482&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.

对沉积岩石的研究是地球科学家的记录，山脉的外观和演变以及气候如何变化。沉积物沉积经历了侵蚀，这两者都消除了部分的rocord，并通过使它们靠近地球表面的岩石来冷却，这项研究将使用岩石标题的地球标志，而这些岩石标题在沉积期间没有地质的地区。该研究将调查超大陆的分手，全球气候和地形上的变化将与Ilso与爱达荷州自然博物馆合作，从事合作，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。并参观在落基山脉的农村地区的博物馆。不合格，而岩石记录传统上被视为地球历史上的岩石记录中的漏洞。大陆的构造历史。他的记录现在是最近的概念和分析。这项研究将沿着700公里的劳伦斯岩石在巨大的不整合物下方进行样品，并产生四个holisthermal山丘，以填补岩石记录中的十亿年间隔。西方劳伦氏菌的几何形状和文本演变缺失了这种能力。没有覆盖teton范围和西南蒙大拿州的Neopokoic A，并且（3）量化了proterokoic热力学的座椅内变异性，以评估Sampl，从并被认为是值得通过Toundation的知识分子优点Meriter影响影响审查标准的评估值得支持的。