Geological Map 1 : 25,000 (Historical GK25)
The first complete geological survey of the State of Brandenburg was carried out between 1874 and 1939. This includes the area that we know as Berlin today, which was mapped between 1875 and 1883. The Prussian Geological State Institute was in charge of the collection of the geological information.
At first glance, this data seems outdated. Some information, however, remains relevant even today. The reasons are two-fold: the maps were recorded at a scale of 1 : 25,000. The much more recent Geological Outline, however, only provides information at a scale of 1 : 50,000. The historical map is therefore much more detailed. What is more: the historical geological map of Berlin serves as a record of the original structures below ground. During urban development, pools and wetlands, for example, were filled or cleared over the years. Their previous locations are of great interest to projects aiming to remove impervious covers from soil or to restore individual areas. This knowledge can support the rewetting of peatlands, restoring of pools or soils and biotopes influenced by groundwater.
In light of this, this historical record was digitised between 2009 and 2013, resulting in the map presented in the Environmental Atlas. Therefore, not only the data itself but also some rock type names, some of which summarised here for clarity reasons, must be understood in their historical context.