Isopach map

Isopach is a line in the geosciences ( iso ) of the same cardinality of a geologic layer in the map display a Isopachenkarte.

Use and meaning of Isopachenkarten

Be Isopachen as contour lines ( contour lines ) together as lines in Isopachenkarten. Only through this cartographic compilation Isopachen for evaluation are useful.

The representation of Isopachen in maps is mainly for arable formations and in research projects of interest. Examples include the appearance of

• Deposits or hope areas
• Extensive sedimentary layers, such as on ocean floor
• Mass raw materials such as coal and salt
• Specific geological horizons
• Eismächtigkeiten in glaciers
• Thickness distributions of volcanic ash during volcanic eruptions.

Isopachenkarten from other representations can be derived, such as the representation of the thickness as a color code.

Production of Isopachenkarten

The existing data ( data from the literature, our own studies ) displayed the geological body, such as the thickness of a glacier at certain points or the thickness of a coal layer with different routes of a mine are entered in a map view. Between the individual data, the gradation in thickness is then interpolated. In simple cases, this can be done for example, by the distance of the data points is divided by the thickness difference between the two data points to determine the thickness increase per unit distance. Depending on the desired increment the point can be determined between the two points, corresponding to a thickness displayed.

Example: A Isopachenkarte of a glacier is to be drawn in shades of Isopachen of 50 m. At point A, the thickness of the glacier ice is 100 m, at point B it is 200 m, the difference is that is 100 m. The two points are 1.000 m apart. The calculation yields ten meters thickness difference at 100 m distance between the points. A thickness difference of 50 m is therefore equal to a distance corresponding to the map 500 m.

After identifying all the necessary powerful points that are connected by Isopachen.

Data bases of Isopachenkarten

Based on the determination of Isopachen are usually point-or line -shaped, as well as rare -dimensional data of the thickness displayed geological body.

Punctual data on widths come from primarily

• Geological outcrops such as cliffs, quarries, road cuts and mines
• Holes of various kinds such as exploration drilling
• Scientific drilling
• Continental deep drilling programs such as the continental deep drilling program of the Federal Republic of Germany ( KTB ) and the International Continental Scientific Drilling Program ( ICDP )
• Marine deep boreholes as the international Ocean Drilling Program ( ODP) and Deep Sea Drilling Project ( DSDP )

Illustrative data on line widths can be obtained by winning

• Systematically applied seismic profiles
• GPR
• Gravimetry and associated models for the vertical and horizontal course of density

Extensive thickness data are obtained from

• Surface mapping
• Geophysical mapping methods such as Ultrasound measurements
• Geoelectric mapping
• Geomagnetic mapping
• Seismic mapping with sufficient data density