Erratischer Block Sigmaringen
Stone on a long journey
Close to the premium hiking trail there is a rock on the wayside that is only inconspicuous at first glance. At a closer look one recognizes: this mysterious block looks completely different from the limestones usually known from the Alb. The weathered surface is dark, irregularly coloured and looks strangely "striped"
Geologists call such a rock "Paragneiss", a transformation rock (metamorphic rock). It is formed under high pressure and temperatures only when sedimentary rocks are sunk to greater depths. This happens, for example, during extensive mountain building processes such as the formation of the Alps.
Over time, the rocks of the Swabian Alb have been lifted and tilted slightly towards SE, but not folded and sunk to depth. This rock does not originate from the Swabian Alb, but is a so-called erratic block (from lat. errare "to wander around, to roam around").
How did it get to this place?
As a natural cause there is only one explanation: glaciers! The ice spreading during the Riss-glaciation period, trapped this boulder in the Alps and brought it all the way to the area around Sigmaringen.
When the Rhine Glacier retreated again and the ice melted, it carefully deposited it. And that's where it has been for over 150 thousand years and still shows today how far the Rhine Glacier's ice sheet has extended to the Swabian Alb.
Such rare finds are messengers from the past, who can tell the landscape history of the Swabian Alb to those who know its significance.
This explains why this boulder was declared by the LGRB as a geotope worthy of protection and deserves to become the 1st GEOPOINT in the district of Sigmaringen.
Address
Geopoint Erratischer Block Sigmaringen
(Landkreis Sigmaringen)
