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: 2347490
• 负责人: Marissa Tremblay
• 金额: $ 24.42万
• 依托单位: Purdue 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=2347490&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 in understanding 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.

悬崖是陡峭的斜坡，延伸了数百英里，并将两个相对平坦的区域分开，一个区域沿着大陆的海岸，另一个沿着内陆。由于板块构造，沿着与另一个大陆分离的许多大陆的边缘发现了悬崖。如果在大陆分开时形成悬崖，科学家不了解当今的悬崖如何到达其位置，然后仍然是景观的重要特征。此外，一些科学家认为悬崖的形成是最近发生的，与分离的大洲无关。研究人员将调查何时在澳大利亚东南部成立的伟大悬崖以及它到达当今地点的速度。他们将使用有关在悬崖和计算机模型周围记录的过去侵蚀率的信息来做到这一点，这些信息可以模仿悬崖形成和撤退的过程。为该项目生成的新数据和模型将有助于了解世界各地悬崖的起源。该项目支持2个早期职业女性PI，研究生和本科教育，并通过既定的视频系列支持课程，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机施加新的限制，其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纹开始有关。 100-85 MA。然而，最近的模型和观察提出了有关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品样品样品样品中收集Apatite 4HE/3HE数据集，这将记录在悬崖期间由景观演化模型预测的适度的散发量。他们将在冷却的时间和幅度上使用磷灰石4HE/3HE约束，以告知新的配对景观演化和热模型。这将使他们能够重新评估有关澳大利亚东南部的地貌进化的近半个世纪的老范式。这样一来，他们将对大陆裂纹如何塑造被动边缘的长期地形演变以及其他因素的重要性（例如地幔热条件在推动岩石上升和悬崖形成中的重要性）的重要性。这项奖项反映了NSF的法定任务，并通过评估基金会的评估和广泛的影响。