Erratic boulders in the Basel Region

This project involves the updating of an existing inventory of large blocks, ('Findlinge' in German) that arrived in our region on the backs of glaciers. Current science has allowed us to more precisely designate, or to re-designate, the origin of some of these erratics.

Erratic boulders are large rounded pieces of rock that were transported on glacial ice during the last great ice ages to their current location. Most erratics arrived in the Basel region as a result of movements of the Rhône Glacier around 200,000 years ago. They are generally different in composition from the rocks that are native to the area in which they rest, and are thus very noticeable.

The project reappraises the erratics of the Basel region that were catalogued by Karl Strübin in 1916 and Hansjörg Schmassmann in 1955. It is possible that some of these rocks have been removed and broken up since the latter survey. The detailed inventory update on the ground will involve observations of the location, state of preservation and macroscopic rock composition.

Using microscopic studies, we will describe the erratics from the point of mineral composition and this will allow us to draw conclusions about the history of their formation, metamorphism and glacial transport. Scientific knowledge of Alpine rocks acquired over recent decades enables us to more precisely designate an area of origin.