Landscape of Switzerland without Unconsolidated Deposits

The present-day Swiss landscape is the result of the successive removal and depositing of loose rock. Glaciers impacted the Swiss Plateau multiple times over the course of ice ages and, in doing so, gouged out the valley floor and abraded the rock surface. Some of the valleys were dug out so deeply that they are significantly below today’s valley floor level and, in some places, even below the present-day sea level. Rivers also carved themselves into the loose rock and bedrock. The rock surface in the Swiss Plateau today is therefore not a reflection of the landscape that came before, but rather the result of a complex sequence of different erosion events. In subsequent episodes of ice ages or interglacial periods, the valleys refilled with loose rock. As a consequence, large parts of Switzerland are now covered with a layer of loose rock of varying thickness.

To illustrate what Switzerland would be like without loose rock, the rock surface of relevant areas of Switzerland was mapped and the thickness of the loose stone determined (sometimes by drilling into it). These data about the rock surface and the thickness of the loose rock provide crucial indications for understanding the quaternary geological processes and shedding light on the development of the landscape. However, they are also of central importance for the prevention of natural hazards, in particular damage from earthquakes or ground movements, planning subterranean construction works and in hydrology, geological prospecting (seismology and gravimetry), managing raw materials and harnessing geothermal energy.

The map can display the rock surface with contour lines as it would look without loose rock and can also show the thickness of the loose rock. This is derived from the difference in altitude between the present-day ground surface level and the bedrock.