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塑造山脉带的根本问题：构造板块之间的碰撞，将土地推到高海拔地区，以及侵蚀山脉。气候强烈影响侵蚀，部分原因是它决定了冰川的形成位置，并随后侵蚀地貌。首要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，那里为这种调查提供了一个天然的实验室。研究人员将使用一个模型来估计过去的温度和降水范围，这也将提高对以前的自然气候变化及其如何影响山脉生长的理解。研究人员将整合不同机构的一系列跨学科专业知识，以实现这些目标，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。研究人员将开展外展活动，例如与K-12科学教师合作，参加博物馆科学主题展览，以及他们机构的开放日。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，将一种力量的影响或特征与另一种力量区分开来可能是困难的。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，这种影响似乎非常明显。邻近的集水区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。本研究着重于两个总体假设：（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）确定年龄未知的冰川沉积物的日期，这将限制气候变化发生的时间，（ii）进行冰川气候建模，这将提高他们对过去温度和降水变化幅度的理解;（2）冰河时代气候直接通过冰川侵蚀影响景观发展，间接通过河流网络变化。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（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.