The vibrant marshlands in Oberfernau are a pivotal location in the study of glacier and climate development. The marshlands are formed of peat, sand, silt and clay and offer fascinating insights into the development of glaciers and climate fluctuations over several millennia. The dark layers of peat formed during warmer periods. In colder periods, lighter sediment drained into the ground carried by melting glacial water.
The marsh deposits have been repeatedly examined since 1943. Recently, in 2017, a tree trunk was found in the marsh which was found to be around 8600 years old. Back then, the marshes were surrounded by tall woodland which was pushed back by the encroaching glacier as of 3000 B.C.