Hydrogeological overview map of Lower Saxony 1: 200000 – Base of the Upper Aquifer Complex (WFS Service)
Description
The map “Base of the upper aquifer complex” illustrates the large-scale distribution and depth of the upper aquifer complex (meters to NN). Depending on the information density, the information on the depth situation is more or less summarised. If only partially further subdivisions are possible within a color area, these depth information appears as colored lines in the surfaces.
In this map, all sands (up to the fine sand area) and gravel whose silt or clay content is less than 5 % are classified as aquifers. For example, due to the layer description, a very weakly sluggish fine sand is still referred to as an aquifer, while a weakly sluggish fine sand is referred to as low water conductive.
In the looser rock areas of Lower Saxony, two superordinate aquifer complexes are distinguished. The upper aquifer complex consists of sands and gravel of the Pleistocene as well as sands of the Pliocene and the Upper Miocene. The lower aquifer complex consists of permeable sediments of the lower to mid-Mocene, the so-called lignite sands. The two aquifer complexes are separated by the groundwater inhibitor Oberer Glimmerton, which consists of sluggish-tony sediments of the middle to upper Mioocene. In the areas where the Upper Glimmerton is missing as a separating intermediate layer (groundwater inhibitor), only one aquifer complex is usually formed. This case occurs both in the area of deeply cut gutters and in the area of strongly elevated salt sticks. In the eastern part of Lower Saxony, the Upper Glimmerton has been demolished. In these areas, therefore, only one aquifer complex is represented and referred to as the upper aquifer complex, although in these areas it is also attributed to the permeable sediments of lignite sands, which otherwise form the lower aquifer complex. The base of the upper aquifer complex is either the Upper Glimmerton or, in its absence, submiocene to oligocene clays and sills.
On the map, two areas are distinguished in the color scale: 1. Areas where the aquifer complex is unstructured because either the separation layer Glimmerton is missing or a lower submiocene aquifer is not formed. 2. Areas in which the aquifer complex is divided, i.e. the Upper Glimmerton is widely distributed and separates an upper from a lower floor.
It is possible that regionally other low-permeable sediments, such as quaternary basin clays, can take over the function of separating intermediate layers, which then result in a spatially limited division of the aquifer complex into two or more groundwater levels. On the basis of the available data, however, too few statements can be made about the area-wide distribution of low-permeable quaternary sediments, since they do not have a constant appearance like the mica tone over larger areas, but can also be very different in their facies over short distances. Therefore, they cannot be taken into account in this overview map, although they are often of great importance for regional groundwater hydraulics. The thickness of the upper aquifer complex is shown in a separate map.
Resources
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https://nibis.lbeg.de/net3/public/ogc.ashx?NodeId=134&Service=WFS&Request=GetCapabilities& |
Tags
- infofeatureaccessservice
- ogc::wfs
- opendata
- inspireidentifiziert
- nibis-metadaten
- sgd_hydrogeologie