Glacial Landforms

As part of the inner mountain ranges, the Monte Perdido Massif (also known as Tres Sorores) stands on the upper course of the Arazas River (Ordesa Valley) and the Cinca River (Pineta Valley). The glacial complex topping Monte Perdido is located within the National Park, on the south face of the massif (north-east oriented / NE). It is higher than 2700m above sea level and covers approximately 40ha.

It can be accessed from Bielsa by the A-2611, driving along the Pineta Valley. The signposted area of the car park and the camp site is located 14km from Bielsa. Take the track to Larri until you reach the bridge across Los Churros Gorge; the path heads on westwards for 4 hours until reaching the Pineta Balcony (Bolán de Marmorés), a stunning viewpoint over the glacial complex.

The glacial complex on the north-east face of Monte Perdido.

Geological Context

The Monte Perdido Massif is formed by materials from the Upper Cretaceous and the Paleogene, dramatically folded by the Alpide orogeny. On its NE face, we find the glacial complex on an uneven terrain. In the past, the glacier lay on three different levels (still observable in 1935) although it currently lies on the two upper levels: the Upper Monte Perdido Glacier and the Lower Monte Perdido Glacier.

The largest glaciation in the Pyrenees took place 60000 years ago (Sancho, et al., 2003), when the lower limit of perpetual snow was between 2000m and 2300m above sea level, whereas currently it is located between 2800m and 3000m above sea level. It is supposed that glaciers withdrew from the Pyrenees 11000 years ago. However, during the Little Ice Age, glaciers in the Pyrenees recovered and even increased their movement./p>

Geological Significance

The height and NE orientation of the glacial complex that is sheltered by a large massif exceeding 3000m above sea level, constitutes an ideal environment for snow, exposure to sunshine and wet Atlantic winds. The proper local micro-climate preserves one of the last remaining glaciers in the Iberian Peninsula, and one of the southernmost glaciers in Europe. The Pyrenean glaciers have been declared Natural Monuments.

Although the Monte Perdido Glacier is definitely withdrawing, it is still an important place to study glacial dynamics, from ice formation (from snowflakes, through granular snow and firn, to glacier ice) to ice flow.