Bavaria's most beautiful geotopes (11)
The geotope "Sandsteinfelsen Nürnberger Kaiserburg" is the type locality for the "Burgsandstein" named after it, a geological layer unit of the Keuper that is widespread in Franconia.
The geological formation of the "Triassic" (252 to 201 million years ago) is more widespread in Germany than any other. It got its name from the tripartite division into red sandstone - shell limestone - Keuper. During the Triassic, our climate was predominantly dry and desert-like. Towards the end of the Keuper period it slowly got wetter. At that time, the area around Nuremberg was on the eastern edge of a shallow sea that bordered on the Bohemian-Vindelice highlands in the east. From there, rivers poured large amounts of sand into the shallow basin. This part of the Keuper is therefore called "Sandsteinkeuper". A special layer of sand was named Burgsandstein, after the rock on which the Nuremberg Imperial Castle stands.
The castle sandstone can be seen both on the mountain flanks and in many places in the castle complex. It is a fine to medium-grained sandstone that, in addition to predominantly quartz grains, contains a certain proportion of the mineral feldspar and is therefore referred to as "arkose". The mostly red-brown color of the rock comes from its iron oxide content, which is typical for dry climates in which it was formed. Elsewhere, silicified wood and dinosaur tracks have also been found in this sandstone.
Scientific and economic importance
The Burgfelsen of the Kaiserburg in Nuremberg is the type locality of the Burgsandstein. This is what geologists call the place where rock was first scientifically described and its name defined.
The economic importance of Burgsandstein
Burgsandstein is widespread in Franconia. It also forms the heights and flanks of the Keuperberge in the Nuremberg area. It was once widely known as the "building block of Nuremberg" and highly valued as an important raw material for buildings (e.g. the old town of Nuremberg). In and around Nuremberg it was broken in many places, such as in today's zoo. Where it is less consolidated, it is now mined as sand for the construction industry.
Extract from lfu.bayern.de