Step into the Ice Age in Northern Switzerland
09.12.2022 In order to understand what the area of what is now Northern Switzerland looked like during and after the last ice age, researchers at BFH and the University of Bern are studying sediment deposits left behind by glaciers.
During the Ice Age, which began 2.5 million years ago and lasted until 11,700 years ago, the earth experienced cold periods in which huge glaciers covered large parts of the earth – including the area of today's Northern Switzerland. About 115,000 years ago was the beginning of the last ice age. During this time, glaciers began to move from the Swiss Alps to the Swiss Plateau, bringing with them rock debris of various sizes. As temperatures rose, the glaciers melted, leaving behind rocks and sediments that prove that glaciers once covered large parts of the world and Northern Switzerland.
Investigation of subglacial and fluvial processes
The study of these sediments plays an important role in understanding the past landscape of Northern Switzerland. This includes studying the subglacial processes and the fluvial processes of over-deepened valleys. For these investigations, the geotechnical laboratory of the Bern University of Applied Sciences and the Institute of Geology of the University of Bern worked together. Within the scope of the project, 11 boreholes with a total depth of 1800 metres were analysed, with the deepest borehole in Andelfingen being 324 metres.
Understanding the geological history of Switzerland
The BFH geotechnical laboratory carried out two types of tests in particular: Atterberg limit tests and oedometer tests. These tests have provided important information about the properties of sedimentary deposits. The Atterberg limit is used in particular to determine the properties of the fine particles of the soil and the natural water content of overdeep basin fills. This helps to distinguish between mass movements and ground moraines. It can be assumed that subglacial moraines have a very low water content because they were subjected to maximum pressure from the glacier, which led to diffusion of water and maximum compaction of the sediments. Another important value is whether or not the sediment sample was loaded by the former glacier in the past. The presence and thickness of glaciers was determined by analysing the results of the oedometer tests.
The two institutions actively collaborated on this project and are now preparing future collaborations to better understand the geological history of Switzerland.