Mapping (geosciences)

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The mapping is in the earth sciences , the spatial detection of geologic , soil science , engineering geological or other geo-scientific data in the field. This work is based on a precise topographical map that can serve as a base map . Special questions or working in less developed areas require a previous survey of the terrain , in which the geodesy or topography support the mapping .

Examples

geology

In geological mapping , the nature of the rock in the mapping area , which may be covered by soil , is systematically recorded as completely as possible. Ideally, the data sources used are larger natural and artificial daily outcrops , small pits created by the mapper himself and, especially in relatively heavily leveled terrain, also reading stones , rock fragments in the roots of uprooted trees and manually drawn drill cores (in exceptional cases also piling core soundings). During the field work, in addition to addressing the rock, measuring the structural values ​​(see brushing and falling ) and / or taking a profile at the exploration, discovery or sampling points, among other things, an attempt is made to identify prominent layers (see bench (stratigraphy) , leading horizon ) or striking changes in the rock structure (lithology change), which are often synonymous with the boundary (the contact) of two formations , to be followed in the terrain. In this regard, conclusions can be drawn from the presence of morphological (e.g. terrain levels ), hydrological (e.g. source outlets ) and botanical (e.g. abrupt changes in the local flora) abnormalities. Geological data from the deeper subsurface, which u. a. are of great use for the understanding of the tectonics of a mapping area, especially in basement provinces or young fold mountains , can possibly be obtained by driving through mines , examining drill cores from deep boreholes or using geophysical methods such as seismics . The finished geological map is a synthesis of all the data recorded during the mapping work, whereby this data was partly interpreted in the context of common doctrines and naturally unavoidable gaps in the database were interpolated.

The map basis for geological mapping and other types of mapping is usually a large-scale topographical map of the area to be mapped. If large-scale geological maps of this area have already been published, which is the rule for regions in industrialized countries, they can serve as a (always to be questioned) orientation aid.

Soil science

The pedological mapping is initially carried out on the basis of geological and biological information, which is why it represents an integrative mapping method and incorporates the procedures of other types of mapping. Since the construction of excavation pits (open soil profiles ) requires approval and is very complex, the number of them usually remains very low in the context of a mapping. A classification (addressing) biological and geological features together with an analysis of the humus layer, however, allow a very precise pedological identification of the existing soil . Further exploration possibilities are given by methods such as a pile-driving core sounding .

Settlement archeology

One technique used in settlement archeology is phosphate mapping. The phosphate content of the soil is mapped. Human uses of land, such as living, arable farming, and cattle breeding cause inputs into the soil, which are very stably bound to certain soil particles and therefore allow conclusions to be drawn about the uses even after a long time. Other inputs such as nitrogen, calcium and potassium are quickly washed out, which is why they do not allow comparable statements. Different soil horizons can be examined because phosphate shifts slowly in the soil. It is not possible to date the entries. The prerequisite for the archaeological significance is the absence of significant recent phosphate inputs and significant changes in soil. The sampling grid is adapted to the area to be examined. A coarse grid, for example for finding settlements, and a very narrow grid within buildings can be selected.

literature

  • Rudolf Hohl (ed.): The history of the development of the earth . 6th edition. Werner Dausien Verlag, Hanau 1985, ISBN 3-7684-6526-8 , p. 497 f .

Individual evidence

  1. ^ Association of State Archaeologists in the Federal Republic of Germany: Excavation Technician Handbook (PDF; 150 kB)