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坡，将两个相对平坦的区域分开，一个沿着大陆海岸，另一个则更深入内陆。在数百万年前由于板块构造而与另一个大陆分离的许多大陆的边缘都发现了悬崖。如果悬崖是在大陆分离时形成的，那么科学家们就不明白当今的悬崖是如何到达它们的位置，然后长期保持地貌的突出特征的。此外，一些科学家认为悬崖的形成是最近才发生的，与大陆分离无关。研究人员将调查澳大利亚东南部大悬崖的形成时间以及它到达现在位置的速度。他们将利用悬崖周围岩石中记录的过去侵蚀率信息和可以模拟悬崖形成和后退过程的计算机模型来做到这一点。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 PI、研究生和本科生教育，并通过旨在支持 K-12 学习的既定视频系列支持课程向 K-12 进行推广。 该项目旨在对澳大利亚东南部悬崖后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后退的原因。澳大利亚东南部的悬崖通常与大约始于 1997 年的大陆裂谷有关。 100-85马。然而，最近的模型和观察提出了关于悬崖形成的时间和起源的问题。为了区分悬崖起源假设，研究人员将从垂直于澳大利亚东南部悬崖的基岩样本横断面收集磷灰石 4He/3He 数据集，这将记录景观演化模型预测的悬崖退缩期间的适度折返量。他们将使用磷灰石 4He/3He 对冷却时间和幅度的约束来为新的配对景观演化和热运动模型提供信息。这将使他们能够重新评估有关澳大利亚东南部地貌演化的近半个世纪的古老范式。在此过程中，他们将对大陆裂谷如何塑造被动边缘的长期地形演化，以及地幔热条件等其他因素在驱动岩石隆起和悬崖形成中的重要性有更深入的了解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。