Diatom sludge
Diatomaceous sludge or silica sludge describes an unsolidified sediment in seas and lakes, which is formed from diatoms or their shell and skeletal remains. The sediment characterizes cool to cold waters and is therefore found mainly in arctic areas or the deep sea in areas from 1,000 to 4,000 m depth. In the area of upwelling areas in which cold, nutrient-rich ocean currents lead to high primary production , diatomaceous sludge can be formed as the main sediment in shallow water areas near the coast, for example in front of the coastal area of Namibia influenced by the Benguela Current .
Diatomaceous mud currently covers around 8 percent of the sea floor , mainly in a belt between 60 ° south and 40 to 60 ° north latitude.
Importance as sedimentary rock
Diatomaceous sludge is the preliminary stage of the sedimentary rock kieselguhr or silica , which is formed when the layers of algae are pressed and compacted by the load of subsequent sediments (e.g. clays ). Diatomaceous earth consists mainly of amorphous (non-crystalline) silicon dioxide (SiO 2 ) and is very porous. 1 ml of pure kieselguhr contains around 1 billion diatom shells or their fragments.
literature
- Keyword “diatom sludge” in: Herder-Lexikon der Biologie. Spectrum Akademischer Verlag GmbH, Heidelberg 2003. ISBN 3-8274-0354-5
- Murawski, H. (1992): Geological Dictionary. Ferdinand Enke Verlag Stuttgart, ISBN 978-3-432841090