Photo: the working group for the new Tectonic Map; Filippo Schenker is third from the right.
Switzerland has a new Tectonic Map (TK500) that offers the opportunity to explore and better understand the dynamics of the Swiss subsurface. This edition represents a significant update of the geometry, distribution and nomenclature of tectonic units and structural elements for the whole of Switzerland and neighbouring regions. The units group together rocks with a common geodynamic history and are separated from each other by tectonic discontinuities. This fourth edition is based on the previous one from 2005, but incorporates the various geological maps published since then.
Filippo Schenker, head of the Geology Department of the Institute of Earth Sciences (Department of environment constructions and design SUPSI), collaborated with swisstopo editor Yves Gouffon as co-author of a section on the Lepontine Alps and contributed to its definition and description. This work made it possible to introduce a new palaeogeographical domain, called Lepontic.
In addition, explanatory notes to the Tectonic Map, of which Schenker is also co-author, have been drawn up for the first time. The notes describe in detail the 187 tectonic units in Switzerland.
The digital version of the Tectonic Map provides access to around 200 sub-units, providing a better understanding of the Swiss subsurface. The colours have been adapted to better highlight the connection between the crystalline basement and the sedimentary layers deposited above it.
The map is available at swisstopo and can also be consulted online.
Two new domains: the Lepontic and the Salassic
The Lepontic, once considered a subunit of the Pennidic domain, is now identified as a domain in its own right. It lies on the margins of the ancient European plate and comprises geological units specific to the Lepontine Alps. The Salassic groups a number of units that were once part of the Austroalpine domain, but which have a distinct tectono-metamorphic history. The term Salassic derives from a Celtic tribe, the Salassi, who settled in Valle d’Aosta and the Sesia region at the same time as the Helvetians north of the Alps and the Leponzi between Val d’Ossola and Leventina.