Bog iron
Bog iron refers to impure iron deposits that develop in bogs or swamps by the chemical or biochemical oxidation of iron carried in the solutions. In general, bog ores consist primarily of iron oxyhydroxides, commonly goethite (FeO(OH)). It was discovered during the Pre-Roman Iron Age, and most Viking era iron was smelted from bog iron.
Iron-bearing groundwater typically emerges as a spring. The iron is oxidized to ferric hydroxide upon encountering the oxic environment of the surface. Bog ore often combines goethite, magnetite and vugs or stained quartz. It is not clear whether the magnetite precipitates upon first contact with oxygen, then oxidizes to ferric compounds, or whether the ferric compounds are reduced when exposed to anoxic conditions upon burial beneath the sediment surface and reoxidized upon exhumation at the surface.
See also
- Limonite
- Iron ore
- Ore genesis
- Acidithiobacillus ferrooxidans (iron oxidizing bacteria)
External links
- Hurstwic: Iron Production in the Norse Era
- Talzhemir's Bog Iron Page
- Bog Iron Industry in The Pinelands
- The Iron Industry in New Jersey
- Bog Iron Formation in the Nassawango Watershed, Maryland U.S. Geological Survey: Open-File Report 03-346
Categories
Iron | Chemical processes | Economic geology | Metallurgy