Norra Kärr or Norra Kärr Alkaline Complex is an intrusive

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

cropping out at the boundary between Östergötland and Småland, Sweden. The complex is chiefly made up of

peralkaline Peralkaline rocks include those igneous rocks which have a deficiency of aluminium such that sodium and potassium are in excess of that needed for feldspar. The presence of aegerine (sodium pyroxene) and riebeckite (sodium amphibole) are indicati ...

nepheline syenite Nepheline syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are al ...

and is rich in exotic minerals. Rocks of the complex intruded into the

Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions ( eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...

-aged Växjo granites of the Transscandinavian Igneous Belt. Alfred Elis Törnebohm was the first to describe the rocks of Norra Kärr in 1906. Norra Kärr was discovered a few years earlier during regional

geological map A geologic map or geological map is a special-purpose map made to show various geological features. Rock (geology), Rock units or stratum, geologic strata are shown by color or symbols. Bed (geology), Bedding planes and structural features such ...

ing by the Swedish Geological Survey. The complex derives its name from a local farm, which translates into English as "Northern

Fen A fen is a type of peat-accumulating wetland fed by mineral-rich Groundwater, ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as ...

". In 1968 Harry von Eckermann published his investigations on the complex defining its boundaries and confirming the view of it as an intrusion. A study has shown that the elevated

rare-earth element The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides ( yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silv ...

concentrations in the bedrock in the Norra Kärr area are particularly well reflected in high contents of these elements in the

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

Dryopteris filix-mas ''Dryopteris filix-mas'', the male fern, is a common fern of the temperate Northern Hemisphere, native to much of Europe, Asia, and North America. It favours damp shaded areas in the understory of woodlands, but also shady places on hedge-banks, ...

''. This raises the possibility for the fern species to be used in biogeochemical prospecting. Norra Kärr is one of the two known sites where the mineral jinshajiangite can be found naturally, the other being in China.

Mine project

The Norra Kärr mine project represents one of the largest

zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...

reserves in Sweden having estimated reserves of 58 million tonnes of ore grading 1.7%

metal. Since 2009, the Canadian company Tasman Metals has owned the mining rights and explored for

rare earth elements The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides (yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous sil ...

in the Norra Kärr area. In February 2016 the supreme administrative court of Sweden withdrew Tasman's exploitation concession for Norra Kärr.

References

External links

Bryta jordartsmetaller i Norra Kärr? - Presentation av Olov Holmstrand, 2016-04-02
(in Swedish), Naturskyddsföreningen i

Tranås Tranås () is a locality and the seat of Tranås Municipality, Jönköping County, Sweden with 14,197 inhabitants in 2010. Overview It is close to the lake Sommen in the north of Småland. Its main commercial center is located along the main stree ...

wedish Society for Nature Conservation in Tranås
Vattnets väg från Norra Kärr - Presentation av Stellan Hamrin, 2016-04-02
(in Swedish) Naturskyddsföreningen i Tranås wedish Society for Nature Conservation in Tranås {{Geology of Fennoscandia Geology of Sweden Mesoproterozoic geology Mining in Sweden Geography of Jönköping County Geography of Östergötland County