(Last updated: 11.05.2007)
|
|
Norsk versjon | ||||
| THE ???? DATABASE | |||||
| Occurence 0 - 000 FEIL | |||||
| (Object Id: ) (Last updated: 11.05.2007) |
|||||
|
|
| Location |
| County: | Municipality: | Mangler () |
| Map 1:50000: | Oslo (1914-4) | Map 1:250000: | Oslo |
| Coordinate system: | UTM-Zone 33 - EUREF89/WGS84 |
| East: | 598100 m. | North: | 6644600 m. |
| Longitude: | 10.7548870 | Latitude: | 59.9257720 |
| Show on map |
|
|
| 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 25.04.2024 |
Copyright © 2024 Geological Survey of Norway |