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 Östergötland (; English exonym: East Gothland) is one of the traditional provinces of Sweden (''landskap'' in Swedish) in the south of Sweden. It borders Småland, Västergötland, Närke, Södermanland and the Baltic Sea. In older English li ...

and

Småland Småland () is a historical Provinces of Sweden, province () in southern Sweden. Småland borders Blekinge, Scania, Halland, Västergötland, Östergötland and the island Öland in the Baltic Sea. The name ''Småland'' literally means "small la ...

, 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 indicat ...

nepheline syenite Nepheline syenite is a holocrystalline Intrusion, 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 varie ...

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

Paleoproterozoic The Paleoproterozoic Era (also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the Proterozoic eon, and also the longest era of the Earth's geological history, spanning from (2.5–1.6 Ga). It is further sub ...

-aged Växjo granites of the Transscandinavian Igneous Belt.

Alfred Elis Törnebohm Alfred Elis Törnebohm (16 October 1838 – 21 April 1911) was a Swedish geologist, best known today for his study of the overthrust of the Caledonian range. After studies at the Royal Institute of Technology (KTH) 1855-1858, he worked at ...

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 geological map or geologic 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 ground or surface water. It is one of the main types of wetland along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires ...

". 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 rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set o ...

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

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

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

''. 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; it has Symbol (chemistry), symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyis ...

reserves in

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

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 rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set of ...

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 Urban areas in Sweden, 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 locat ...

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 Jönköping Municipality Ödeshög Municipality