Decay

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In soil science, gelling refers to the redistribution of iron and manganese in soils that are influenced by groundwater .

process

In semiterrestrial soils, there is groundwater close to the surface . This leads to the development of groundwater-influenced horizons (G horizons).

The permanently wet areas below the water table are not ventilated. In this oxygen-free environment, the general ambient conditions are anaerobic ( reduction horizon ) and the iron that is common in the soil is gray, reduced iron (II). Iron (II) is easily soluble in water and can therefore be transported. Other metals such as dissolved manganese are also found but are nowhere near as important.

By capillary forces , groundwater is drawn up through the fine pores of the soil into ventilated zones, just as paper held in water soaks up over time. Dissolved, reduced metals such as iron (II) are also transported upwards with the water. As soon as it comes into contact with oxygen, it is oxidized into orange iron (III) ( rust ) , which is sparingly soluble and precipitates immediately. Since the fine pores serve as transport routes, they are water-filled and reducing (gray). The coarse pores, on the other hand, contain air and are oxidizing (orange). The typical marbling of the glazed floor is created. Sometimes oxidized iron can accumulate in the transition to the ventilated zone, so that turf iron stone forms.

In addition to iron, manganese is also relocated. Since this is more easily soluble, it is also transported further. Black manganese oxide concretions (manganese tippiness) occur a little above the marbling.

Soil classes

Gleying primarily defines the soil types of the gleye class . It is also present in marshes and to a lesser extent also affects floodplains and beaches .

Differentiation from pseudo-gleying

If there is stagnant or backwater , it is referred to as pseudo-gleying (soil class pseudogleye ). In principle, similar processes take place, but with two important differences:

  • No reduction horizon is established.
  • The marbling of the pseudogleye is reversed (coarse pores gray and fine pores orange).