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

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.