Possibility of marine clay is based on Quaternary (superficial deposit) maps in different scales and data set for marine limit. Superficial deposit surface types below marine limit are classified according to the possibility of finding marine clay and can be roughly divided into six classes. The map service 'Possibility of marine clay' ('Mulighet for marin leire') has been created as a guide to reading a Quaternary geological map. It is important to point out that the map service does not display new information in relation to the Quaternary map. It is also important to check the scale of the Quaternary map, and it should also be taken into account that the estimated marine limit may be associated with some uncertainty. For this reason, polygons, which cross or lie near the marine limit, are included in the classification. However, a hatch shows which part of these polygons lies above the marine limit, and which can therefore generally be disregarded with regard to the possibility of marine clay. Exceptions will be areas where other soil types are on top of marine clay, but then the latter will only occur below the marine limit. Data for water-covered areas are not delivered below the marine limit because the surficial deposits have usually not been mapped (even if some polygons for technical reason cross the shoreline). It should be noticed, however, that marine clay deposits are common within water-covered areas below the marine limit including new, loose sediments. See below and use above link 'Display productpage' to read more about the application including uncertainties and use (only in Norwegian).

Marine limit indicates the highest level the sea reached after the last Ice Age. Information about marine limit is central in the work of delimiting areas with marine clay in Norway. Marin limit indicates the highest level of marine sediments deposited on land. Issues involving such deposits may be excluded over the marine limit, which is important information in i.a. public planning. For example, quick clay and landslides in marine fine-grained deposits and fjord deposits as marine clay only occur under marine limit. Furthermore, groundwater quality below marine limit can be affected by relict salt water and clay can limit the spread of aquifers. The data consists of point registrations, lines and polygons. Lines and polygons are modeled from points and a 10 meter digital elevation model. The dataset is nationwide.

The map application shows geological themes NGU have available and which are of interest within the planning process when it comes to the field of Landscape, Resources and Safety.