Fracture (geology)

A column (English: fissure or crevice ) is in geology and mining a gaping joint or parting surface within a rock body.

Education

Small fissures opened by tectonic movements, such as earthquakes, expanded into columns, faults, but also by the intrusion of igneous rock melts and the cooling of volcanic lava. The magnitude of a column is in the range of several millimeters to meters in width and several centimeters to hundreds of meters extension in length and in depth.

In the sense of Geodynamics includes the crevasse to the geological column.

System

Arnold of Lasaulx (1882 ) distinguished endokinetische columns where there is the risk of the formation within the rocks themselves, and exokinetische columns where this is outside.

Entokinetische columns thus caused by, for example,

• Increases in volume of the rock (eg, through the incorporation of water into anhydrite, Dilatationsspalten )
• Volume reductions of the rock (such as by cooling or escape of water column contraction )

Exokinetische columns (or Dislokationsspalten ) caused by

• Collapse of cavities ( collapse columns)
• Arching of the crust (eg, by penetration of a magmatic body into the ground, breaking columns)
• Folding of rock layers (bending columns)

Filling of gaps

Near-surface gaps are often filled again with weathering debris of the surrounding rock and sediment ( "Sediment transitions " ), such as in the Korbacher column. Deeper columns can, however, enable the rise of groundwater and thermal water, which then emerge at the surface as springs. If mineral-rich waters that seep from the surface, or hydrothermal solutions from the deep, circulate in open columns can be eliminated so-called gap minerals on the walls of a column until it is fully closed ( " heals "). If such programs contain economically valuable mineral ores, they are referred to as transitional deposit. For columns that are filled with magmatic gangue, are dikes.

Gas flows in columns

For some columns - such as karst caves - penetrates felt cool air to the surface. For other columns also Vapours may rise as it is, for example, handed down by the oracle of Delphi, which should have put the seer Pythia in a trance.