Collaborative Research: Landscape Evolution in the McMurdo Dry Valleys: Erosion Rates and Real-time Monitoring of Rock Breakdown in a Hyperarid, Subzero Environment

合作研究：麦克默多干谷的景观演变：超干旱、零度以下环境中的侵蚀率和岩石破碎的实时监测

• 批准号: 1744895
• 负责人: Jennifer Lamp
• 金额: $ 36.64万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1744895&HistoricalAwards=false
• 关键词: Collaborative; Research; Landscape; Evolution; McMurdo

Non-technical AbstractThe McMurdo Dry Valleys region of Antarctica is one of the coldest, driest, and windiest places on the planet, and is often used as a comparison for the surface of Mars. It is also the largest ice-free region of Antarctica, and thus its deposits and landforms contain unique records of past climate not accessible elsewhere in the Antarctic continent or the world. In order to accurately interpret any geologic feature, however, we must understand how it forms and changes through time. In particular, in the Dry Valleys, we have a poor understanding of the rates and causes of one of Earth's most fundamental geologic phenomenon - physical rock breakdown. For example, the Dry Valleys lack moisture, which is thought to play a key role in rock breakdown in most other locations on the planet. What serves to fracture rocks in this seemingly inert environment? This project aims to answer that question by 'listening' as rocks crack in the Dry Valleys. We will instrument boulders with sensors that act as miniature seismographs, recording even the smallest microcracking on and within the rocks. At the same time, we will monitor the weather and environment around the rocks to record the conditions that trigger cracking events. While we collect these data, we will gather rock samples from deposits of different ages (from thousands to millions of years old) in the Dry Valleys. Measurements on these samples will allow us to see how quickly rocks breakdown and how their characteristics change over geologic time. The combined datasets will allow future scientists to more accurately understand the paleoclimates and landscapes of Antarctica, and possibly even Mars. This project will also serve to support two female investigators in a field where women are still largely underrepresented. The project will also provide unique exposure and experience to students, ranging from elementary students to the undergraduate and graduate students who will be working directly on various aspects of the project. Technical AbstractRocks in the McMurdo Dry Valleys experience some of the lowest erosion rates on Earth. However, our current understanding of the relative role that different weathering factors (moisture, freezing temperatures, thermal cycling, salt crystallization or hydration, and wind abrasion) play in these and other environments is limited. Further, in the Dry Valleys, there has been no systematic evaluation of the variance in weathering and associated rock erosion rates, which may change significantly as a function of subaerial exposure duration, lithology, and texture. This research seeks to (1) characterize the primary drivers of rock breakdown, (2) better quantify erosion rates, and (3) determine the lithological and environmental factors that influence weathering and erosion in the Dry Valleys. Rock breakdown (cracking) will be recorded in real-time on in situ boulders using a custom acoustic emission monitoring system. By coupling acoustic emission data with micrometeorological measurements at and near rock surfaces, this study will directly test hypotheses relating to the environmental drivers of rock breakdown under this unique polar desert climate over short (minute to monthly) timescales. Cosmogenic nuclide techniques including a novel combination of 6 isotopes (Be-10, Al-26, He-3, Ne-21, Cl-36, C-14) together with rock property measurements (e.g., strength, elastic moduli, thermal properties) will be used to elucidate the complex relationship between long-term (kyr to Myr) boulder erosion rates, lithology, rock properties, and subaerial exposure duration. By synthesizing these measurements with short-term cracking data from the acoustic emission system, the proposed work will thoroughly examine which lithological and environmental factors and grain-scale processes are driving geomorphic evolution in the Dry Valleys. By constraining boulder erosion rates and determining their sensitivity to rock properties and age, the results will be directly applicable to cosmogenic nuclide exposure age studies in this region. Additionally, the resulting information on weathering processes and their relationship to rock morphology in the Dry Valleys can be used to address hypotheses as to formation of similar rock morphologies on Mars. The Project Investigators will participate in an elementary school outreach program run by Gonzaga University, and the project will support an undergraduate and graduate student.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.

南极洲的麦克默多干谷地区是地球上最冷、最干燥、风最大的地方之一，经常被用来与火星表面进行比较。它也是南极洲最大的无冰区，因此它的沉积物和地貌包含了南极大陆或世界其他地方无法获得的过去气候的独特记录。然而，为了准确地解释任何地质特征，我们必须了解它是如何形成和随时间变化的。特别是在干谷，我们对地球上最基本的地质现象之一——物理岩石破裂的速度和原因知之甚少。例如，干谷缺乏水分，这被认为在地球上大多数其他地方的岩石破裂中起着关键作用。在这个看似惰性的环境中，是什么使岩石破裂？这个项目旨在通过“倾听”干谷岩石破裂的声音来回答这个问题。我们将用充当微型地震仪的传感器来测量巨石，记录岩石上和岩石内部哪怕是最小的微裂缝。与此同时，我们将监测岩石周围的天气和环境，记录引发裂缝事件的条件。在收集这些数据的同时，我们将从干谷中不同年龄（从数千年到数百万年）的沉积物中收集岩石样本。对这些样品的测量将使我们看到岩石分解的速度有多快，以及它们的特征在地质时期是如何变化的。这些综合数据集将使未来的科学家能够更准确地了解南极洲，甚至火星的古气候和地貌。这个项目还将在一个妇女人数仍然不足的领域支助两名女调查人员。该项目还将为学生提供独特的接触和经验，从小学生到本科生和研究生，他们将直接参与项目的各个方面。技术摘要麦克默多干谷的岩石经历了地球上最低的侵蚀率。然而，我们目前对不同风化因素（湿度、冰冻温度、热循环、盐结晶或水化、风蚀）在这些和其他环境中所起的相对作用的理解是有限的。此外，在干谷，还没有对风化和相关岩石侵蚀率的变化进行系统的评估，这些变化可能随着地面暴露时间、岩性和质地的变化而发生显著变化。本研究旨在(1)确定岩石破碎的主要驱动因素；(2)更好地量化侵蚀速率；(3)确定影响干谷风化和侵蚀的岩性和环境因素。岩石破裂（开裂）将使用定制的声发射监测系统实时记录在原位巨石上。通过将声发射数据与岩石表面及其附近的微气象测量相结合，本研究将在短时间（分钟到月）内直接测试与这种独特的极地沙漠气候下岩石破裂的环境驱动因素有关的假设。宇宙成因核素技术包括6种同位素（be -10、Al-26、He-3、Ne-21、Cl-36、C-14）的新组合，以及岩石性质测量（例如强度、弹性模量、热性质），将用于阐明长期（kyr至Myr）岩石侵蚀速率、岩性、岩石性质和地面暴露时间之间的复杂关系。通过将这些测量结果与来自声发射系统的短期裂缝数据综合起来，这项工作将彻底研究哪些岩性和环境因素以及粒度过程推动了干谷的地貌演化。通过限制岩石侵蚀速率并确定其对岩石性质和年龄的敏感性，结果将直接适用于该地区宇宙成因核素暴露年龄的研究。此外，关于风化过程及其与干谷岩石形态关系的所得信息可用于解决火星上形成类似岩石形态的假设。项目调查员将参与冈萨加大学开展的一项小学外展计划，该计划将支持一名本科生和研究生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。