Neogene/Paleogene - volcanoes und meteorites
In the Neogene/Paleogene period, 66 million years ago to 2.6 million years ago, the rock layers of the Swabian Alb were tectonically uplifted and tilted slightly to the southeast. Except for a short interruption (see "Neogene/Paleogene - Burdigal Sea and its cliff line"), the area was now mainland. A subtropical climate prevailed and the limestones previously deposited in the Jurassic Sea were now intensively karstified and eroded.
The youngest rock layers of the Jurassic and perhaps also deposits of the Cretaceous period are no longer preserved here today and cannot provide any information about these periods in the Swabian Alb.
However, striking brown-red globules and nodules can be found in karst crevices or cavities. This so-called "Bohnerz" has been preserved as an insoluble residue of Neogene/Paleogene karstification and consists mainly of the mineral goethite, an iron ore.
Other impressive witnesses of the Neogene/Paleogene can be seen in the Alb foothills: The cone-shaped mountains of today's landscape are former volcanic vents (e.g. the Limburg near Weilheim an der Teck or the Spitzberg near Beuren). Volcanic blast craters such as the Randecker Maar also bear witness to the "Swabian volcano". Around 350 volcanic vents were active in the central Swabian Alb between 18 and 10 million years ago. Good to know: The Höwenegg near Immendingen on the south-western edge of the Alb, is not part of the "Swabian volcano" - it is part of the Hegau volcanism.
This period also witnessed an event that left a significant mark on the landscape: the impact of a meteorite around 15 million years ago. It left behind the world-famous Steinheim Basin, a circular crater, still very well preserved today, with a diameter of around 3.5 kilometres. The Ries crater near Nördlingen, which was formed by an impact at about the same time, separated the formerly coherent rock complex of the Swabian and Franconian Alb.
The diverse fauna and flora of the Neogene has been preserved through finds in lake deposits in the Steinheim Basin and the Randecker Maar or in the "Böttinger Marmor" rock.
