Norsk versjon
THE ORE DATABASE
Occurence 301 - 013 Akersberg gruve
(Object Id: 6609)
(Last updated: 11.05.2007)

Location
County: Oslo Municipality: Oslo (301)
Map 1:50000: Oslo (1914-4) Map 1:250000: Oslo
Coordinate system: EU89-UTM Zone 32
East: 597890 m. North: 6644247 m.
Longitude: 10.7511330 Latitude: 59.9240530
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Resource
Resource Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Resource Subtype: Lead
Element(s): Pb Zn
Importance
Raw material meaning: Little Importance (reg. 18.02.2015)
Historical: Yes , (Confirmed 08.mai.2006 by Havard Gautneb)

Resources and production
Activity: Mining Reserves:
Operating method: Underground mining Historical production:


Products
Element/product Crude ore grade or quality Reg. date
Ag 08.05.2006
Pb 08.05.2006

Operations
From - To Activity Comments
1100 - 1612 Regular production Company/Institution :Krogods

Mineralization
Era: Paleozoic Period: Permian
Genesis: Hydrothermal vein Form: Plate
Main texture: Cavity filling Min. distribution: Irregular (scattered)
Main grain size: Medium grained (1-3 mm) Main alteration: Silicification
Strike/Dip: 150 / 90 Direction:
Plunge:
Stratigraphic classification of host rock
Era: Paleozoic Period: Ordovician
Province: Oslo Region
Geotec.unit:
Tectonic complex:
Igneous complex:
Group: Oslogruppen Formation: Elnesformation

Mineralogy
Relationship Mineral Amount
Gangue mineral Quartz Major mineral (>10%)
Gangue mineral Calcite Major mineral (>10%)
Ore mineral Pyrite Major mineral (>10%)
Ore mineral Sphalerite Major mineral (>10%)
Ore mineral Chalcopyrite Subordinate mineral (1-10%)
Ore mineral Pyrrhotite Subordinate mineral (1-10%)
Ore mineral Argentite Accessory mineral (<1%)
Ore mineral Molybdenite Accessory mineral (<1%)
Ore mineral Hessite Accessory mineral (<1%)

Information(s) in free text format
Free text
Forekomsten er befart og forekomsdata registert av Odd Nilsen, UiO 1988-1990

Bibliography:
From NGU's Reference Archive:
Nilsen, Odd; Bjørlykke, Arne , 1991
Silver mineralization in the ancient Akersberg mine, Oslo.
;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.71 (2);121-128 pages
Abstract:
Recent archaeological excavations have uncovered parts of the ancient silver workings of the Akersberg mine in the city of Oslo. Pb-Zn mineralization is confined to a partially brecciated Permian diabase intrusion which intersects the Ordovician slate/limestone sequence of the area. The sulphides occur as steeply dipping veins - partly within the diabase and partly at the diabase contact. The main ore minerals are pyrite, sphalerite, galena and chalcopyrite, argentite, sternbergite, hessite and covellite are accessory constituents. Brecciation with "crack-and-seal" structures are common and reflest several episodes of mineralization. Supergene alteration processes have led to the silver enrichment in secondary silver minerals that coat the primary sulphide minerals. The diabase dyke follows the NW-SE-trending fracture pattern of the Oslo district, and subsequent development of cross-cutting fissures in the diabase may have allowed the introduction of ore-bearing fluids. Lead isotope analysis of galenas from Akersberg reveal a pattern comparable to that of other Pb-Zn vein deposits within the Oslo Graben and point to a granitic source of the metals.


The fact sheet was created on 08.12.2021

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