Marl

Marl or with strongly solidified deposits also marl or marl ( OHG mergil, Latin marga, according to Pliny Naturalis historia originally from the Gallic ) is a sedimentary rock. Marl has very different formation conditions. It occurs, when the fine material ( clay, silt ) deposited and simultaneously precipitated lime or also deposited.

Composition

The rock contains both lime and siliceous components are usually smaller grain size ( clay and / or silt ). Coarser material (sand and gravel) may be present. At higher lime additives is called calcareous marl, with a high clay content of clay marl. Marl deposits that cover all grain size classes are referred to in the art as diamictite.

After Carl Wilhelm Correns (1949 ) can be distinguished:

  • High percentage limestone (up to 95 % lime, 5 % clay )
  • Marly limestone (up to 85 % lime, 15 % clay )
  • Marl (up to 75 % lime, 25 % clay )
  • Calcareous marl (up to 65 % lime, 35 % clay )
  • Marl (up to 35 % lime, 65 % clay )
  • Marl (up to 25 % lime, 75 % clay )
  • Marl clay (up to 15 % lime, 85 % clay )
  • Marly clay (up to 5 % lime, 95 % clay )
  • High percent clay (up to 0 % lime, 100 % audio)

Occurrence

Marl and marl stones are spread worldwide and quite frequently. Known marl deposits in Central and Western Europe are located in South Limburg (Netherlands ), in particular the marl caves of Maastricht and Valkenburg aan de Geul are a local tourist attraction. Other large marl deposits are located in the Mainz Basin. In the Austrian Petrology special local marl forms are also called Tegel.

Use of marl

Marl is an important raw material for cement production. In agriculture, mainly drained wetlands ( marshes and swamps ) have been improved with marl in the past; the lime neutralized the acid soils, the clay stabilized the soft ground, so that the fields were accessible and navigable.

Since the marls was mistakenly equated with a soil fertilization, but in reality except Lime did not soil nutrients (phosphates, nitrates), were in the absence of other fertilizer (compost, manure, and later guano, superphosphate or similar). Fields soon barren and exhausted - and therefore referred to as emaciated - what then transmitted as " emaciated ", has been purchased " powerless " or " used up" in our everyday language.

Only good on calcareous marl soils and there on steep south or southwest documents grows, the Italian Nebbiolo grape.

Pulheim Old High German Gaulish language Field (agriculture) Till Integrated Authority File
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