4. Glaciers of the Dolomites

In order to consider the relationship between the landscapes of the Dolomites and glaciation, we must first take a leap back in time by around 20,000 years to when the glaciers occupied all of the Alpine valleys, including those of the Dolomites, with thicknesses greater than 1,500 m (up to 2,000 m in the Bolzano area). Chronologically, we are in the so-called Last Glacial Maximum, the period characterised by maximum expansion of glaciers.

Western glacier of Sorapiss, ph. Matteo Visintainer

In this period, only the highest peaks emerged from this “sea” of ice, in the form of isolated peaks (nunataks). The glaciers originating from the large Dolomite groups joined together to create a network of branches that intersected between one valley and the next. Some slid over the current Dolomite passes, which at the time served as points of transfluence. The particular diversity and distribution of rocks in the Dolomites has also enabled identification of the direction of movement of glaciers, performing specific analyses not only on morphology, but also looking at the distribution of debris transported along the valleys and from one valley to another. This has enabled the identification of examples of transfluence, for example, from the Adige basin to the Piave basin through the Gardena and San Pellegrino passes.

The traces that remain most evident to this day in terms of glacial morphogenesis are those attributed to successive phases of retreat (melting) and advance of the glaciers. These occurred with intermittent and irregular periods during the late glacial period, which began around 17,000 years ago. The most frequently encountered forms that document the presence of glacial tongues gradually retreating within the topography of the Dolomites are glacial moraines, steps, glacial valleys, hanging valleys, roches moutonnées, arêtes and glacial cirques.

The latter are very common near the heads of valleys in eight of the nine Dolomite Systems making up the World Heritage Site, and it is there that the majority of the small remaining glaciers in the Dolomites are found; the last remnants of that great sea of ice that concealed the impressive forms of the “Pale Mountains” around 20,000 years ago. The small System 8 – Bletterbach, with its deep-cut valley that fed into the Adige valley features no traces or evidence of glacial processes due to its origin and altimetric characteristics. Of the other eight systems, only System 1 – Monte Pelmo – Croda da Lago, system 2 – Marmolada, System 3 – Pale di San Martino, San Lucano, Belluno Dolomites and Vette Feltrine, System 5 – Northern Dolomites, and System 9 – Brenta Dolomites, are still home to glaciers or glacierets.

Read more details here: Glaciers of the Dolomites UNESCO World Heritage Site, prof. Alberto Carton.