Bog iron

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.

Iron made from bog ore will often contain residual silicates, which can form a glassy coating that grants some resistance to rusting.

Bog iron was widely sought in colonial America. Lake Massapoag in Massachusetts was drawn down by deepening the outlet channel in a search for bog iron. (Diana Muir, Reflections in Bullough's Pond, University Press of New England, 2000) In New Jersey, bog ore was mined and refined and used for the production of tools, wrought iron rails (many of which still grace stairs in Trenton and Camden), taking advantage of its natural rust-resistance. During the American Revolution, the iron was used for cannon balls for the American forces. Bog iron was also found on the Eastern Shore of Maryland. The remains of a commercial smelting operation near Snow Hill are now a state and national historic site. Known as Furnace Town, it was called the Nassawango Iron Furnace after the nearby creek. The commercial furnace ran from about 1825 to 1850.

In an episode of the TV program "The Worst Jobs in History", presenter Tony Robinson was shown searching for bog ore.

ee also

* Limonite
* Iron ore
* Ore genesis
* Acidithiobacillus ferrooxidans (iron oxidizing bacteria)
* History of ferrous metallurgy

External links

* [ Hurstwic: Iron Production in the Norse Era]
* [ Talzhemir's Bog Iron Page]
* [ Bog Iron Industry in The Pinelands, New Jersey]
* [ - a free wiki dedicated to the preservation of iron furnaces]
* [ Bog Iron Formation in the Nassawango Watershed, Maryland] U.S. Geological Survey: Open-File Report 03-346
* [ American Society of Mechanical Engineers] , Nassawango Furnace landmark.
* [ ASME PDF file] with detailed reconstruction drawings of the furnace and surroundings.
* [ Nassawango Furnace] at the Maryland Historic Trust.
* [ “A Brief History of Nassawango Iron”]
* [ Furnace Town] , Snow Hill, Worcester County Maryland.

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Look at other dictionaries:

  • Bog iron — Iron I ron ([imac] [u^]rn), n. [OE. iren, AS. [=i]ren, [=i]sen, [=i]sern; akin to D. ijzer, OS. [=i]sarn, OHG. [=i]sarn, [=i]san, G. eisen, Icel. [=i]sarn, j[=a]rn, Sw. & Dan. jern, and perh. to E. ice; cf. Ir. iarann, W. haiarn, Armor. houarn.]… …   The Collaborative International Dictionary of English

  • bog iron — noun see bog iron ore …   Useful english dictionary

  • bog iron — noun deposits of mixed oxides and hydroxides of iron formed when iron bearing groundwater emerges onto the surface …   Wiktionary

  • bog iron — noun an impure, porous form of limonite deposited in bogs …   English new terms dictionary

  • bog iron ore — Iron ore consisting of hydrated iron oxide minerals such as limonite and goethite formed by precipitation of groundwater flowing into wetlands. Bacterial action contributes to formation of the ore. Economically useful deposits can regrow within… …   Universalium

  • bog iron ore — noun or bog iron : a porous variety of limonite * * * bog iron ore, a loose, porous variety of limonite found in bogs or water …   Useful english dictionary

  • bog iron ore — pelkių rūda statusas T sritis chemija apibrėžtis Pelkių dugne nusėdęs geležies hidroksidas. atitikmenys: angl. bog iron ore; brown iron ore rus. болотная руда …   Chemijos terminų aiškinamasis žodynas

  • bog-iron ore — /bog uy euhrn, bawg /, Mineral. a deposit of impure limonite formed in low, wet areas. Also called bog ore. [1780 90] * * * …   Universalium

  • bog-iron ore — /bog uy euhrn, bawg /, Mineral. a deposit of impure limonite formed in low, wet areas. Also called bog ore. [1780 90] …   Useful english dictionary

  • bog iron ore — noun Deposit of porous, impure limonite found in bogs and swamps …   Wiktionary

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