Entstehung des geologischen Atlas der Schweiz (1:25'000)

The geological maps of Switzerland of the Federal Office of Topography swisstopo have so far been the only comprehensive data set on the structure of the subsurface. They thus make an important contribution to the exploration and sustainable use of the subsurface and form an important basis for decisions in areas such as tunnelling, ground investigations, natural hazards and science.

Creation and content

The basis of a geological map is primarily the geological mapping of the earth's surface (e.g. outcrops in stream incisions or excavations). Geological units are judged according to their composition, age and storage and presented with various graphical elements on a topographical basis.

The field mapping is supported by modern survey methods such as evaluation of aerial photographs or digital elevation models and supplemented with further basic data such as drilling or geophysical measurements. Both digital data sets and 3D models of the underground are derived from the maps.

After 20 years of mapping work, Atlasblatt No. 173 Elm was published in 2021. On a scale of 1:25,000, it covers a central section of the Geological Map of the Glarus Alps 1:50,000 by J.Oberholzer ("Oberholzer Map") from 1942. In the area of the Atlas Leaf Elm lies the heart of the UNESCO World Heritage Site Tectonic Arena Sardona: The Glarus thrust with the Tschingelhörnern and the Martinsloch. Here the "magic line" can be seen particularly well.

On a hike over the Segnespass from Elm to Flims (Stage 6, 73.06 Sardona World Heritage Trail) you can see the Glarus thrust up close.