Collaborative Research: Uplift or climate change? Determining the primary driver of deep canyon incision in the eastern cordillera, southern Peru

合作研究：抬升还是气候变化？

• 批准号: 1842172
• 负责人: Nadine McQuarrie
• 金额: $ 27.11万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1842172&HistoricalAwards=false
• 关键词: Collaborative; Research; Uplift; climate; change

Competition between the growth of new topography by tectonic uplift and erosion that wears it down occurs in many mountain regions. Earth scientists recognize that the ability of rivers to erode depends on how much water is delivered to the mountains, and that changes between wetter or dryer climates should influence topography. The expectation is that changes in climate and the resulting change in erosion are reflected in the topography of a landscape. This project focuses on the Eastern Cordillera of southern Peru, where deep canyons carved into the Central Andean Plateau margin reflect either tectonic uplift or an increase in erosional efficiency due to climate change. The research incorporates newly-developed methods for diagnosing the effects of climate on topography as part of a field-based investigation to determine the degree to which climate-driven changes in erosional efficiency are responsible for canyon cutting. New remote analysis methods are used to differentiate signatures of tectonic uplift driven erosion and climate driven erosion in topography. Improving the fidelity of these remote methods has considerable societal value because they are an inexpensive and efficient means of hazard assessment in areas where the presence or absence of tectonic uplift, and the resulting effect on seismicity, are uncertain. Additionally, this project wll benefit society by: 1) essential STEM training of three US graduate students including two women, as well as several Peruvian undergraduates; 2) international collaborations with both Peruvian and German universities; and 3) improved STEM education development in Peru and US at the undergraduate, graduate, and professional levels.Determination of an active tectonic driver of mountain uplift and the geometry of related structures is critical to resolving how strongly climate and tectonics are coupled. This project tests competing hypotheses for the proximal drivers of canyon cutting into the Eastern Cordillera: incision driven by active rock uplift vs. incision into a previously uplifted plateau margin triggered by climate change. Integration of observations and analyses of the deformation history, landscape morphology, precipitation patterns, and spatial and temporal patterns of erosion and exhumation is used to definitively and quantitatively evaluate the relative importance of active rock uplift and climate change in landscape evolution. Analyses focus on: 1. estimating millennial-scale erosion rates from cosmogenic 10Be concentrations in modern river sands, 2. assessing the role of rainfall in the relation between topography and erosion rate, 3. analyzing cooling ages of low-temperature thermochronometers (AHe, AFT, ZHe) provided by a complementary study, 4. refining geologic mapping and developing balanced cross sections, and 5. integrating all data in models to quantitatively test hypotheses. Results will have broad implications for: 1. the general applicability and fidelity of proposed methods for diagnosing the primary causes of canyon cutting based on analysis of geomorphic data, 2. further development of a methodology to quantitatively link geometry, displacement and rates on faults to exhumation rates, erosion rate patterns and the resulting landscape morphology, 3. quantitative, observation-based understanding of the sensitivity of erosion rates to annual rainfall, and 4. understanding of the nature and strength of linkages among climate, topography, erosion, and tectonics.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.

在许多山区，构造抬升造成的新地形的生长与侵蚀造成的侵蚀之间存在着竞争。地球科学家认识到，河流侵蚀的能力取决于输送到山脉的水量，而潮湿或干燥气候之间的变化应该会影响地形。 人们期望气候变化和由此产生的侵蚀变化反映在景观的地形中。该项目重点关注秘鲁南部的东科迪勒拉山脉，那里的深峡谷雕刻在安第斯高原中部边缘，反映了构造抬升或气候变化导致的侵蚀效率的增加。该研究采用了新开发的方法来诊断气候对地形的影响，作为实地调查的一部分，以确定气候驱动的侵蚀效率变化在多大程度上导致峡谷切割。新的远程分析方法用于区分构造抬升驱动的侵蚀和气候驱动的地形侵蚀的特征。提高这些远程方法的保真度具有相当大的社会价值，因为在存在或不存在构造隆起以及由此对地震活动产生的影响不确定的地区，它们是一种廉价且有效的灾害评估手段。此外，该项目还将通过以下方式造福社会：1）为三名美国研究生（其中两名女性）以及几名秘鲁本科生提供必要的 STEM 培训； 2）与秘鲁和德国大学的国际合作； 3) 秘鲁和美国本科生、研究生和专业水平的 STEM 教育得到改善。确定山脉隆起的活跃构造驱动因素和相关结构的几何形状对于解决气候和构造耦合的强度至关重要。该项目测试了峡谷切入东科迪勒拉山脉的近端驱动因素的相互竞争的假设：由活动岩石隆起驱动的切入与由气候变化引发的先前隆起高原边缘的切入。综合变形历史、景观形态、降水模式以及侵蚀和折返的时空模式的观测和分析，可以明确、定量地评估活动岩石隆起和气候变化在景观演化中的相对重要性。分析重点是：1. 根据现代河沙中的宇宙 10Be 浓度估算千年尺度的侵蚀率，2. 评估降雨在地形和侵蚀率之间关系中的作用，3. 分析补充研究提供的低温测温仪（AHe、AFT、ZHe）的冷却年龄，4. 完善地质测绘并开发平衡截面，5. 将所有数据整合到模型中以定量检验假设。结果将对以下方面产生广泛影响： 1. 基于地貌数据分析来诊断峡谷切割主要原因的所提出方法的普遍适用性和保真度， 2. 进一步开发一种方法，将断层的几何形状、位移和速率与折返速率、侵蚀速率模式和由此产生的景观形态定量联系起来， 3. 基于观测的定量理解侵蚀速率对每年的敏感性 降雨量，以及 4. 对气候、地形、侵蚀和构造之间联系的性质和强度的理解。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。