What types of glaciers exist in Chile?

What types of glaciers exist in Chile?

There are several different types of glaciers in the world, which form from varying processes, dependent upon the geography and local conditions of climate and landscape. These can range from enormous ice sheets of Antarctica that are kilometres deep, to small mountain glacierets of the Pyrenees which can be mistaken for patches of snow. A general classification of ‘bare-ice’ glacier types can include valley glaciers, tidewater glaciers, piedmont glaciers, ice caps, ice fields and ice sheets (a more complete classification can be found here ¹). With the exception of large ice sheets (found only in Antarctica and Greenland), Chile is home to an almost complete range of glacier types, one of which Santiguinos can see every (clear) day from the city… glaciers El Plomo and La Paloma!

Mountain/Valley glaciers

Typically originating from high mountain regions or icefields, these glaciers move down valleys, looking like tongues of ice. Glaciers such as El Plomo, Bello, Amarillo, Juncal Sur and Universidad are examples of this glacier type. Larger (and longer) valley glaciers typical of Alaska are not common in Chile.

Tidewater glaciers

These are glaciers that reach far enough from their mountain origins to reach water, typically at sea level in fjords (such as Grey glacier or O’Higgins glacier). These glaciers normally ‘calve’ into the water, which means the breaking off of icebergs or larger segments of ice.

Piedmont glaciers

These are types of large land terminating glaciers that flow out of valleys and spread out in a fan shape as they become in contact with relatively flat and open terrain. An example of this type of glacier in Chile is San Rafael glacier.

Ice fields

This term is used to describe a smaller version of a ice sheet, that is still a large expanse of glacier ice governed by its underlying topography. The examples of this type are the North and South Patagonia ice fields, which are the largest single bodies of ice outside of the polar regions.

Ice aprons and volcanic ice caps

This classification belongs to the high quantity of glaciers that exist in various part of Chile, whereby the relatively high elevation permits ice formation and survival on steep sides and/or on the top of the volcanoes. Obvious examples of this are Calbuco, Villarrica ² and San José.

Debris-covered glaciers

Debris-covered glaciers are common in Chile. As the name suggests, they are covered with rocks, boulders and other material accumulated from valley sides, avalanches, rockfalls and the release of rocks held in the ice once it has melted (Figure 1). The rocks covering the glacier can act as a blanket and protect it from melting as rapidly as ‘bare-ice’ glaciers. The variations in the amount of rocks on the surface can produce interesting features such as ice cliffs. A well-studied example is Pirámide glacier (Figure 3).

Figure 1. A schematic for the surface and internal characteristics of ‘bare-ice’, debris-covered and rock glaciers. Source: adapted from Bosson et al. (2016) ³.

Rock glaciers

The classification of this type of glacier is difficult ⁴ and can often be mistaken for debris-covered glaciers, or even just rocks! A rock glacier, unlike a debris-covered glacier, is a mix of ice and rock material throughout the entire body of the glacier (see Figure 1 for this distinction). These glaciers can be found all over Chile, though especially in the central and northern regions. For example, north of 32°S, more than half of the total glaciers that exist are debris-covered or rock glaciers (Figure 2)!

Technical reports even note that in the two most important basins in the central region, the Aconcagua and the Maipo basins, rock glaciers outnumbered clean-ice glaciers by a ratio of 2.3:1 ^5,6.  As seen in Figure 3, various types of glaciers can often exist in the same geographical setting (the same basin), but be affected by unique localised processes.

Figure 2.  A map of Chile marked with the total estimated area of debris-covered and rock glaciers per sector and as a percentage of the total. Data source: Janke et al. (2015) 4. Figure source: Thomas Shaw

3. A map of the El Yeso river basin, Cajón del Maipo, Región Metropolitana, with the presence of three types of mountain glaciers. A ‘bare-ice’ glacier (Bello/Yeso), a debris-covered glacier (Pirámide) and an unnamed rock glacier. The inset photo for Pirámide glacier shows an ice cliff under a debris-covered surface. Background image source: Digital Globe. Photos source: Thomas Shaw

Cited information:

¹ What types of glaciers are there? National Snow and Ice Data Center: https://nsidc.org/cryosphere/glaciers/questions/types.html (Last access 14/03/2019)
² Brock, B. W., Rivera, A., Casassa, G., Bown, F., & Acuna, C. (2007). The surface energy balance of an active ice-covered volcano : Villarrica Volcano , Southern Chile. Annals of Glaciology, 45, 104–114.
³ Bosson, J., & Lambiel, C. (2016). Internal Structure and Current Evolution of Very Small Debris-Covered Glacier Systems Located in Alpine Permafrost Environments, 4 (April). https://doi.org/10.3389/feart.2016.00039
⁴ Janke, J. R., Bellisario, A. C., & Ferrando, F. A. (2015). Geomorphology Classi fi cation of debris-covered glaciers and rock glaciers in the Andes of central Chile. Geomorphology, 241, 98–121. https://doi.org/10.1016/j.geomorph.2015.03.034
⁵ Centro de Estudios Científicos (CECS), 2011. Variaciones Recientes de Glaciares en Chile, Según Principales Zonas Glaciológicas. Dirección General de Aguas (DGA), Santiago, Chile.
⁶ Geoestudios, 2011. Catastro, Exploración y Estudio de Glaciares en Chile Central. Dirección General de Aguas, Santiago, Chile.

Written by Thomas Shaw.
Edited by Equipo Glaciar.