Collaborative Research: Understanding Glacial-Geomorphic-Climatic Changes in the Arid Andes: Cordillera Oriental as a Case Study

该项目旨在解决两个相互竞争的过程如何形成山带的基本问题：构造板块之间的碰撞，将陆地推向高海拔，以及侵蚀，使山脉磨损。气候强烈影响侵蚀，部分原因是它决定了冰川可以在哪里形成，并随后侵蚀景观。总体目标是了解气候变化和冰川如何影响山区发展，特别是通过侵蚀。调查人员将把重点放在安第斯山脉中部的一部分，那里为此类调查提供了一个天然的实验室。这组科学家将根据他们的观测使用一个模型来估计过去的温度和降水范围，这也将提高对过去自然气候变化及其如何影响山脉生长的理解。这些研究人员将整合来自不同机构的一系列跨学科专业知识来实现这些目标，其中包括美国和阿根廷的科学家。该项目促进了至少一名博士后研究员和一名研究生的早期和中期职业发展。研究人员将开展外联活动，例如与K-12科学教师接触，在博物馆举办科学主题展览，以及在他们机构的开放日。气候和构造力在山脉的生长过程中相互作用，特别是通过它们对侵蚀模式的共同影响。然而，区分一种力量与另一种力量的影响或特征可能很困难。研究人员提议在干旱的安第斯山脉探索冰川和气候对景观发展的影响，在那里这种影响似乎非常明显。邻近的流域经历了一系列的冰川地貌条件，从广泛的冰川到轻微的冰川到没有冰川。该研究集中在两个主要假设上：(1)在干旱的安第斯山脉，最后一个冰河时代带来了最冷的条件，但不一定是最大的冰川和降水对景观过程的影响。研究人员将(i)确定未知年龄的冰川沉积物的年代，这将限制气候变化发生的时间；（ii）开展冰川-气候模型，这将提高他们对过去温度和降水变化幅度等问题的理解；(2)冰期气候通过冰川侵蚀直接影响景观发育，通过河流网络变化间接影响景观发育。研究人员将利用碎屑10-Be测量（短时间尺度）和低温热年代学（长时间尺度），以及已知记录构造和气候扰动的地貌指标，评估冰川调节侵蚀的潜在模式。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。

The project seeks to address the fundamental issue of how two competing processes shape mountain belts: collisions between tectonic plates, which push land to high elevations, and erosion that wears mountains away. Climate strongly influences erosion, in part because it determines where glaciers can form and, subsequently, erode the landscape. The overarching aim is to understand how climate changes and glaciers influences mountain development, specifically through erosion. The investigators will focus on a part of the central Andes that provides a natural laboratory for such investigation. The researchers will use a model to estimate past temperature and precipitation ranges based on their observations, which will also improve understanding of former natural climate variability and how it may influence the growth of mountains. The researchers will integrate a range of interdisciplinary expertise at different institutions to accomplish the goals, including scientists in the U.S. and Argentina. The project fosters early and middle-career development for at least a postdoctoral researcher and a graduate student. The researchers will carry out outreach, such as, by engaging with K-12 science teachers, in a museum science-themed exhibit, and at their institution's open house. Climatic and tectonic forces interact with one another in the growth of mountains, particularly through their shared influence on erosion patterns. Yet, distinguishing the influence or signature of one force from another can be difficult. The researchers propose to explore glacier and climatic imprints on the development of landscapes in an environment where such effects appear to be eminently discernible, in the arid Andes. Neighboring catchments experienced a range of glacial geomorphic conditions, from extensively glaciated to marginally glaciated to not glaciated. The study focuses on two overarching hypotheses: (1) In the arid Andes, the last Ice Age brought the coldest conditions, but not necessarily the largest glaciers and precipitation impacts to landscape processes. The researchers will (i) date glacial deposits of unknown age, which will constrain when climate changes occurred, and (ii) carry out glacier-climate modeling, which will improve their understanding of, for example, the magnitude of past temperature and precipitation changes; (2) Ice Age climates impact landscape development directly through glacial erosion and indirectly through fluvial network change. The researchers will assess potential patterns of glacially-modulated erosion using detrital 10-Be measurements (short timescale) and low-temperature thermochronology (longer timescales), and geomorphic metrics that are known to record tectonic and climatic perturbations.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.