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

该项目试图解决两个相互竞争的过程如何塑造山带的根本问题：将陆地推向高海拔的构造板块之间的碰撞，以及侵蚀山脉的侵蚀。气候对侵蚀的影响很大，部分原因是它决定了冰川可以在哪里形成，从而侵蚀了地形。其首要目标是了解气候变化和冰川如何影响山脉的发展，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天然实验室。研究人员将根据他们的观察使用一个模型来估计过去的温度和降水范围，这也将提高对以前自然气候变异性的理解，以及它可能如何影响山脉的生长。研究人员将整合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。研究人员将进行外展，例如，通过与K-12科学教师接触，在博物馆的科学主题展览中，以及在他们的机构的开放参观中。气候和构造力量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，将一种力量的影响力或特征与另一种力量区分开来可能很困难。研究人员建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，在这样的环境中，这种影响似乎是显而易见的。邻近的集水区经历了一系列的冰川地貌条件，从广泛的冰化到略微冰化再到不冰化。这项研究集中于两个最重要的假设：(1)在干旱的安第斯山脉，最后一个冰期给景观过程带来了最冷的条件，但不一定是最大的冰川和降水影响。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，并(Ii)进行冰川气候模拟，这将提高他们对过去温度和降水变化幅度的了解；(2)冰河时代气候通过冰川侵蚀直接影响地形发展，并通过河流网络变化间接影响地形发展。研究人员将使用碎屑10-Be测量(短时间尺度)和低温热年代学(较长时间尺度)，以及已知记录构造和气候扰动的地貌指标来评估冰川调制侵蚀的潜在模式。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.