Collaborative Research: Reevaluating the Timing and Driver of Escarpment Retreat in Southeast Australia

合作研究：重新评估澳大利亚东南部悬崖后退的时机和驱动因素

• 批准号: 2347491
• 负责人: Magdalena Curry
• 金额: $ 31.17万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2347491&HistoricalAwards=false
• 关键词: Collaborative; Research; Reevaluating; Timing; Driver

Escarpments are steep slopes that extend for hundreds of miles and separate two relatively flat areas, one along the coast of a continent and the other further inland. Escarpments are found along the edges of many continents that separated from another continent millions of years ago due to plate tectonics. If escarpments form when the continents separate, scientists do not understand how present-day escarpments reach their locations and then remain prominent features of landscapes for so long. Additionally, some scientists think escarpment formation occurs more recently, unrelated to the continents separating. The researchers will investigate when the Great Escarpment in southeast Australia formed and how quickly it reached its present-day location. They will do this using both information about past erosion rates recorded in rocks around the escarpment and computer models that can mimic the process of an escarpment forming and retreating. The new data and models generated for this project will help them understand the origin of escarpments around the world. This project supports 2 early career women PIs, graduate and undergraduate education, and outreach to K-12 through an established video series supported curriculum that is designed to support K-12 learning. This project aims to place new constraints on the timing of escarpment retreat in southeast Australia, with the broader goal of reevaluating the cause of escarpment formation and retreat. The southeast Australian escarpment is often linked with continental rifting beginning ca. 100-85 Ma. Recent models and observations, however, raise questions about the timing and therefore origin of escarpment formation. To discriminate between escarpment origin hypotheses, the researchers will collect apatite 4He/3He datasets from a bedrock sample transect perpendicular to the southeast Australian escarpment, which will record the modest amounts of exhumation predicted by landscape evolution models during escarpment retreat. They will use the apatite 4He/3He constraints on the timing and magnitude of cooling to inform new, paired landscape evolution and thermo-kinematic models. This will enable them to reevaluate a nearly half-century old paradigm about the geomorphic evolution of southeast Australia. In doing so, they will develop a more robust understanding of how continental rifting shapes the long-term topographic evolution of passive margins, and of the importance of other factors like mantle thermal conditions in driving rock uplift and escarpment formation.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.

悬崖是绵延数百英里的陡峭斜坡，将两个相对平坦的地区分开，一个沿着大陆的海岸，另一个更深入内陆。在数百万年前由于板块构造而与另一块大陆分开的许多大陆的边缘发现了悬崖。如果悬崖是在大陆分离时形成的，那么科学家们不明白今天的悬崖是如何到达它们的位置，然后如此长时间地保持着风景的显著特征。此外，一些科学家认为，悬崖的形成发生得更晚，与大陆的分离无关。研究人员将调查澳大利亚东南部的大悬崖是何时形成的，以及它以多快的速度到达今天的位置。他们将使用记录在悬崖周围岩石上的过去侵蚀速度的信息和可以模拟悬崖形成和后退过程的计算机模型来完成这项工作。为该项目生成的新数据和模型将帮助他们了解世界各地悬崖的起源。该项目支持2名早期职业女性个人投资、研究生和本科教育，并通过已建立的视频系列支持课程扩展到K-12，旨在支持K-12学习。该项目旨在对澳大利亚东南部悬崖撤退的时间施加新的限制，更广泛的目标是重新评估悬崖形成和撤退的原因。澳大利亚东南部的悬崖通常与大陆裂谷联系在一起，开始于大约100-85 Ma。然而，最近的模型和观察提出了关于悬崖形成的时间和来源的问题。为了区分悬崖成因假说，研究人员将从垂直于澳大利亚东南部悬崖的基岩横断面收集磷灰石4He/3He数据集，这将记录在悬崖撤退期间景观演化模型预测的少量折返。他们将利用磷灰石4He/3He对冷却时间和大小的限制来提供新的、成对的景观演化和热运动学模型。这将使他们能够重新评估关于澳大利亚东南部地貌演变的近半个世纪的范式。通过这样做，他们将对大陆裂谷如何塑造被动边缘的长期地形演变，以及地幔热条件等其他因素在驱动岩石隆起和悬崖形成方面的重要性有了更深入的了解。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。