Quantifying long-term aeolian abrasion rates on hard rock surfaces

量化硬岩表面的长期风蚀率

• 批准号: 2314628
• 负责人: Nathan Brown
• 金额: $ 26.16万
• 依托单位: University of Texas at Arlington
• 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: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2314628&HistoricalAwards=false
• 关键词: Quantifying; long; term; aeolian; abrasion

In arid regions, on Earth and on other planets, wind-blown sand erodes and reshapes landscapes. On human timescales, this erosion can be immeasurably small, so it is unclear how long it takes to form these landscapes. This project will use two recent advances in geochemical measurements to measure erosion rates on southern Californian ventifacts, boulders which are eroded by sand blasting during windstorms. Based on these measurements, this project will investigate whether a past shift in climate produced different ventifact erosion rates. These measurements will also test whether erosion by wind-blown sand depends on rock type or height above the ground surface. Several reference rocks will be manually eroded at a known rate and then measured to test whether the predicted erosion rates based on geochemical measurements match the actual, known erosion rates. Finally, this project will create 3-D digital models of all ten studied ventifacts and make them freely available to educators everywhere with an accompanying teaching module. These boulders are rare and difficult to access, so creating photorealistic educational models dramatically increases access to these fascinating geological features. A limited supply of 3-D printed, handheld models will also be provided at no cost to interested classrooms and printing instructions will be posted online.The project goal is to quantify the spatial and temporal evolution of aeolian abrasion rates across the surface of ventifacts using recent advances in optically stimulated luminescence (OSL) and cosmogenic, in situ 10Be and 14C methods. Rates will be measured on lengths ranging from several mm to tens of cm and timescales from decadal to multi-millennial. This project involves five major research tasks: (1) field campaign to two sites in southern California; (2) in situ cosmogenic 14C-10Be exposure age and erosion rate analysis (1 paired 14C-10Be sample per ventifact, totaling 10); (3) OSL depth profile erosion rate analysis of ventifacts (10 OSL depth profiles per ventifact, totaling 100) and manually eroded rock cylinders (3 erosion rates per lithology and 10 lithologies, totaling 30); (4) generation of digital 3-D models from field photographs of 10 ventifacts using structure-from-motion photogrammetry and handheld educational models from 3-D printing along with an accompanying educational video; and (5) presentation of results at conferences and in peer-reviewed journal articles. Project results will demonstrate, for the first time, that luminescence measurements can accurately recover hard rock erosion rates on a mm-scale. Measured rates will benchmark existing but empirically untested abrasion mechanisms.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.

在干旱地区、地球和其他行星上，风吹的沙子会侵蚀并重塑地貌。在人类的时间尺度上，这种侵蚀可能小得不可估量，因此尚不清楚形成这些景观需要多长时间。该项目将利用地球化学测量方面的两项最新进展来测量南加州火山体的侵蚀率，这些火山体是在风暴期间受到喷砂侵蚀的巨石。根据这些测量结果，该项目将调查过去的气候变化是否产生了不同的通风设施侵蚀率。这些测量还将测试风沙侵蚀是否取决于岩石类型或距地面的高度。将以已知速率手动侵蚀几个参考岩石，然后进行测量，以测试基于地球化学测量的预测侵蚀速率是否与实际的已知侵蚀速率相匹配。最后，该项目将为所有十种研究的文物创建 3D 数字模型，并通过附带的教学模块免费向世界各地的教育工作者提供。这些巨石非常罕见且难以接近，因此创建逼真的教育模型可以极大地增加人们对这些迷人地质特征的了解。还将向感兴趣的教室免费提供有限的 3D 打印手持模型，并且打印说明将发布在网上。该项目的目标是使用光受激发光 (OSL) 和宇宙成因、原位 10Be 和 14C 方法的最新进展。速率将根据从几毫米到几十厘米的长度和从十年到几千年的时间尺度来测量。该项目涉及五项主要研究任务：（1）对南加州两个地点进行实地考察； （2）原位宇宙成因14C-10Be暴露年龄和侵蚀率分析（每个产品1对14C-10Be样品，共10个）； （3）喷口体的OSL深度剖面侵蚀速率分析（每个喷口体10个OSL深度剖面，总计100个）和人工侵蚀岩石柱（每个岩性3个侵蚀速率和10个岩性，总计30个）； (4) 使用运动摄影测量结构和 3D 打印的手持教育模型以及随附的教育视频，根据 10 个文物的实地照片生成数字 3D 模型； (5) 在会议和同行评审的期刊文章中介绍结果。项目结果将首次证明，发光测量可以准确地恢复毫米级的硬岩侵蚀率。测量的速率将以现有但未经经验测试的磨损机制为基准。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。