Surface and Subsurface Temperature Monitoring of a Rock Glacier in the Semi-arid Andes

Authors: Miles McIntosh

Mentors: Jason R. Janke, Juk Bhattacharyya

Abstract

Glaciers in retreat often serve as a visual testament to a changing climate. However, the effects of climate change on rock glaciers, with their insulating debris cover, are seldom studied. The Aconcagua River basin, situated in central Chile, offers a unique opportunity. This basin, which spans a transition zone from arid to temperate climates and represents a continuum from rock glacier to ice-exposed glacier, provides an ideal setting to monitor environmental change in a sensitive zone.

For this project, we examine the Tres Gemelos rock glacier complex near Los Andes, Chile. Temperature measurements were collected at the surface and 30 cm below the surface at a 2-hour sampling interval. Data loggers were placed at two locations. One was near the toe of a rock glacier (3,805 m), while the other was on a different lobe at a higher elevation (4,047 m). There are over 43,000 recordings for each monitor from March 2013 through November 2022.

The almost 10 years of data can give us a glimpse into climate trends. The average temperature has increased about 1-2° C over the last decade, with similar trends at both the surface and at depth. Events such as the 2014-2016 and 2018-2019 El Niño and La Niña years and the dates of the first and last snowfall are also examined.

Our analysis holds the potential to significantly enhance our understanding of climate change and its impact on glaciers. Known as “water towers,” rock glaciers store hidden reserves of water within their ice, which is not visible from the surface. This hidden water resource is particularly crucial in regions like Chile, which has been experiencing prolonged droughts. By monitoring temperature fluctuations, we can better understand and manage these vital water reserves, ensuring sustainable water supply during times of scarcity.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5, 2024 doi: 10.1130/abs/2024AM-403304