Database name: |
World Fe-oxide+/-Cu-Au-U (IOCG) deposits |
Compilers: |
Sunil S. Gandhi |
Release date: |
2015-03-04 |
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Deposit name(s): |
Idkerberget |
Political location(s): |
Sweden; Province or state: Dalarna; Nearest community: Borlänge (15 km SW) |
Deposit clan (type): |
Kiruna-type |
Deposit (sub) types: |
stratabound lensoid and irregular bodies in a rhyolite sequence intruded by a large mafic pluton that is metaorphosed to amphibolite; skarn breccias and disseminated ore occur in the deposit ; Reference: Magnusson, N. H., 1970: The Origin of the Iron Ores in Central Sweden and the History of their Alterations; Sveriges Geologiska Undersökning, Serie C, Part 1 and 2, Publication code 643, 491 p. |
Deposit status: |
past producer; Size category: 10 Mt |
Geologic province: |
Svecofennian Orogen |
Geologic subprovince: |
Southern Svecofennian |
Geologic district: |
Berglagen (Ore District) |
Commodities: |
Fe |
Mineralization styles: |
stratiform magnetite layers and lenses; banded; breccia-fillings; dissemination |
Geological ages: |
Late Paleoproterozoic (mineralization) Late Paleoproterozoic (host rocks) |
Tectonic setting: |
continental marginal arc-fore-arc; convergent (host rocks) |
Coincident features: |
stratification in host sequence (ore bodies nearly concordant, with associated brccia-fillings and disseminations) post-ore intrusion (a mafic intrusion, metamorphosed to amphibolite, encloses ore bodies) |
Regional tectonic structure: |
highly deformed zone (late Svecofennian deformation and metamorphism; trend E-W; abundant granite injections) |
Host rocks: |
(1) volcanic; felsic volcanic rocks (post-ore deformation and metamorphism); Magma series/sedimentary package/metamorphic group: calc-alkaline; Depositional setting: continental arc; Metamorphic grade: amphiboliteExternal host rock forms: | intercalated flows and volcaniclastic sediments | Host rock protoliths: | rhyolitic volcanics (rhyolitic flows and volcaniclastics, referred to in older literature as 'leptites') | Internal host rock structures: | porphyritic, fine grained granular and gneissic | Individual lithologies: | rhyolite (altered during mineralization, disrupted by a mafic intrusion, then deformed, metamorphosed and intruded by granites) |
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Alteration signatures: |
skarn: diopside, tremolite, actinolite, chlorite; What was altered: rhyolitic and calcareous host rocks |
Mineralogy: |
(mineralization): magnetite, apatite, hematite, actinolite |
Deposit shape: |
zone of lensoid and irregular bodiesDeposit dimensions: | length: 700 metres thickness: 70 metres depth: 125 metres |
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Qualified comments: |
(Applies to: discovery and development) Mined intermittently from 17th century to 1902 when systematic underground mining started; lasted till 1977; ore averaged 62 % Fe, 0.05 % Mn, 0.6-0.7 % P, 0.017 % S, 5.4 % SiO2, 2 % CaO and 2.2 % MgO. The deposit is comparable with the Grangesberg and Blötburget deposits, 60 and 52 km to the SSW respectively; together they comprised 40 % of the iron ore resources of central Sweden. Reserves unknown. |
References: |
Magnusson, N. H., 1970 |
The Origin of the Iron Ores in Central Sweden and the History of their Alterations |
Sveriges Geologiska Undersökning, Serie C, Part 1 and 2, Publication code 643, 491 p. |
Zitzmann, A. Editor(s)), 1978 |
The Iron Ore Deposits of Europe and Adjacent Areas: Explanatory Notes to the International Map of the Iron Ore Deposits of Europe, 1:2,500,000 (Lists and Tables) |
International Geological Congress, Commission for the Geological Map of the World, Subcommission for the Metallogenic Map of the World, Bundesanstalt fur Geowissenschaften und Rohstoffe, Postfach 51 01 53, D-3000 Hannover 51, Volume II, 386 p. |
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Resource data: |
Disclaimer - Reserves/Resource Data
Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources (NRCan) does not warrant or guarantee the accuracy, completeness or fitness for any purpose of Reserve and Resource information (Data) contained in this database, including whether the Data is compliant with any securities regulations or standards, and NRCan does not assume any liability with respect to any damage or loss incurred as a result of the use made of the Data.
Resource and reserve figures are historical in nature. The Data source provided with each set of figures should be cited if the Data are re-reported. |
50 million metric tons ore; Combined with production?: no; Provisional entry?: yesGrade-commodity information: | Fe: 35 percent Mn: 0.4 percent S: 0.6 percent | Reference: Anonymous, 2000: Swedish Database of Mineral Deposits; Email Percent weights allocated to deposit: 100.0% |