Proglacial sandur: a new landscape is born where the glacier once was
In front of the Forni Glacier lies a vast proglacial plain, a young landscape in a constant state of transformation. Until a few decades ago, this area was covered by ice. This area was covered by ice until a few decades ago. This environment is known as a sandur, a term originating from Icelandic that describes flat surfaces formed by fluvioglacial deposits.
Sandurs are formed when glacier meltwater carries sand, gravel and pebbles, which are deposited as the current slows down. In addition to this process, landslides and debris flows, driven by gravity, help to shape the landscape. The result is a large surface area with complex deposits that are criss-crossed by braided streams that change position over time.
In the case of the Forni Glacier, the sandur has become clearly visible over the last 20 years as the glacier’s terminus has receded. Today, it is a natural laboratory where the interaction between ice, water and sediment can be observed and the glacier’s recent history “read”.
Linguistic Curiosity
The term ‘sandur‘ comes from the Icelandic language and literally means ‘sand’ or ‘sandy plain’. In Iceland, sandur landscapes are spectacular and very extensive. They are formed in front of large glaciers where melt waters carry huge amounts of sediment. Some Icelandic sandurs, such as Skeiðarársandur, are among the largest in the world, covering hundreds of square kilometres.
Geomorphologists have adopted the term to describe similar environments in the Alps, such as the landscape formed in front of the Forni Glacier. Here, the sandur is smaller but equally significant as a landscape in formation, shaped by ice, water, and gravity.
Bibliographical references for further reading
Benn, D.I. & Evans, D.J.A. (2010). Glaciers and Glaciation. Routledge.
Knight, J. & Harrison, S. (2014). Mountain glaciation and geomorphology. Cambridge University Press.
Miall, A.D. (2006). The Geology of Fluvial Deposits. Springer.
Kostaschuk, R.A. (2001). Flow structure and sediment transport in sandur environments. Geomorphology, 38(1–2), 33–52.