Geological Map of Lower Saxony 1: 25 000 — basic card (WMS service)

The Geological Map of Lower Saxony 1: 25 000 (GK25) provides information on the distribution, nature and sequence of rocks up to a depth of two meters below ground surface. In the case of solid rocks, it is usually possible to draw conclusions about the continuation of these rock sequences at greater depths. In the map image and the associated area descriptions, the stratigraphy (age creation) and the genesis (type of origin) are presented and described for each geological unit. Furthermore, the area descriptions contain information on the main petrography part and the secondary part (condition of rocks) as well as the lime and humus content of the individual layers. All units shown and quantified in the map image are abbreviated to the symbol key Geology (PREUSS et al. 1991) explained. The presentation of the geological facts in the base map is subject to certain rules. Rocks of at least 2 metres thickness on the terrain surface are characterised by surface colors, overlapping cases of several layers with beam hatching. Horizontal beam hatching features layer sequences, which consist exclusively of loose rocks, diagonally arranged beam hatches refer to loose rock layers over solid rocks. Wide hatching points to the rocks on the surface of the terrain; layers below are characterised by a thinner hatching. Surface colours as well as colors of the hatchings characterise the respective type of rock. In order to illustrate the natural geological conditions, the original distribution of the rocks is presented in areas with intensive development, although they may be altered by anthropogenic measures (e.g. spilling). The GK 25 is available in two machining stages with different accuracy: either as detailed mapping (special mapping) or as an overview mapping (manuscript card). The overview classifications in scale 1: 25 000 (sheet cut of the TK25) were used for the preparation of the Geological Overview Map 1: 200 000 (GÜK 200) and are already largely generalised for the target scale of the GÜK 200. The processing was done with relatively little time (usually a few weeks to months), so that the area-like resolution is rather low. The individual GK25 are usually not matched with the neighbouring leaves at the edge of the leaf. This can lead to so-called “leaf-edge faults”. The main reasons for this are the different times at which the individual geological maps were drawn up (e.g. a sheet 1929, the neighboring sheet only in 1985) and that detailed and overview classifications are located on neighbouring leaf areas, so that the different processing intensity does not allow a comparison at the edge of the leaf. A revision of all geological maps is currently not possible at this scale level.