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Norsk versjon | ||||
| THE ORE DATABASE | |||||
| Deposit Area 1664 - 021 | |||||
| (Last updated 05.jul.2023) | |||||
Name of Deposit Area : Bjørnmyrgruva |
| (Object Id : 1664,021,00,00) |
| Location |
| County : | Sør-Trøndelag (16) | Municipality : | Selbu (1664) |
| Map 1:50000: | Stjørdal (1621-1) | Map 1:250000: | Trondheim |
| Marking point: | Longitude: | 11.0667030 | Latitude: | 63.3152320 |
| EU89-UTM Zone 32 | (Coordinates IS confirmed) |
| X-coord: | 603539 m. | Y-coord: | 7022380 m. |
|
|
| Commodity |
| Main Type: | Ferrous metals(Fe, Mn, Ti) | Sub Type: | Iron | |
| Element(s): | Fe |
| Production |
| Activity: | Pitting | Reserves: | ||
| Prod. method: | Production: | |||
| Prod. status: | Volume of dump: | 100 m3 |
| Importance |
| Public: | (No data) |
| Economical: | Minor interest , (Confirmed 03.jul.2023 by Jan Sverre Sandstad) |
Mineralization |
| Era: | Paleozoic | Period: | Ordovician | |
| Dating: | Method: | |||
| Genesis: | Volcex | Form: | ||
| Main texture: | Min. distribution: | Massive (>50 % ore minerals) |
| Main grain size: | Main alteration: |
| Strike/Dip: | Direction: | |||
| Plunge: |
| Stratigraphic classification of host rock |
| Era: | Paleozoic | Period: | Ordovician |
| Province: | Caledonides | |
| Geotec.unit: | Trondheim Nappe Complex | |
| Tectonic complex: | Gula Complex | |
| Igneous complex: |
| Group: | Gula | Formation: |
Mineralogy |
| Relationship | Mineral | Amount | |
| Gangue mineral | Quartz | Major mineral (>10%) | |
| Gangue mineral | Biotite | Subordinate mineral (1-10%) | |
| Ore mineral | Magnetite | Major mineral (>10%) |
Lithology: |
| Relationship | Rock | Origin | |
| Host rock | Banded quartzite | Sedimentary Original rock :Exhalite |
|
| Metamorphic facies :Greenschist |
Information(s) in free text format |
| Free text |
| Bjørnmyrgruva ligger i glissen granskog rett vest for ei myr i svært overdekket området ca. 150 m vest for gammelveien over Strandfjellet. Gruva ble drevet på ren magnetittmalm på 1820-tallet av Mostadmark jernverk. Den består av en vannfylt, tilnærmet trekantformet synk med lengste sider 4x6 m. Massiv magnetitt finnes i i fast fjell eller som en større blokk sørøst i synken. På tippen dominerer båndet kvartsittisk bergart i tillegg til finkornet, massiv magnetitt. Det er trolig at mineraliseringen er av samme type som ved Røsbekken som ligger 1,5 km lengre sør. |
Bibliography: |
| From NGU's Reference Archive: |
| Torske, Tore , 1965 |
| Geology of the Mostadmarka and Selbustrand area, Trøndelag. |
| ;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.232;1-83 + ka pages |
| Abstract: | |
| The bedrock of the area consists of metamorphic epiclastic, volcanic, and intrusive rocks of assumed Lower Ordovician age, assigned to, and lithologically matching the rocks of, the Røros, Støren and Lower Hovin Groups of the Trondheim Region. A detailed petrographic description of the rock varieties is given. The metamorphic grade of all rocks corresponds to the Greenschist Facies. - Small ore deposits occur in connection with the volcanic rocks. They comprise pyrite-pyrrhotite ores of the Leksdal Type, mixed pyrite-magnetite ores, and iron oxide ores. - Lithological variations of the sedimentary rocks is tentatively correlated with events during the early periods of the Caledonian Orogeny. - The volcanism within the area seems to have started with a phase of explosive activity, followed by extrusion (mostly submarine) of copious amounts of spilitic lavas; towards the end of the main period of volcanism a new episode of explosive activity has produced what is called the upper pyroclastic horizon, comprising rocks ranging from coarse volcanic breccia to finegrained tuffs. - The intrusive rocks consist mainly of saussurite gabbros and quartz keratophyres. The latter are thought to be intrusive rather than effusive, and evidence is offered to support this. In some places the character of pyroclastic material points to a quartz keratophyre parentage. Thus, quartz keratophyres may have occurred both as intrusive and volcanic rocks. |
Fieldsamples |
| Sample No. | Sample type | Miscellanrous | |||||
| Bjørnmyrgruva-1 | Dump |
|
| NB! All analyse values are shown at the end of the printout.: |
Analyse Results |
| from |
| Deposit Area 1664 - 021 Bjørnmyrgruva |
Element analyses |
( *=parts pr. million, #=parts pr.billion, Negative values means below detection limit value.) |
| Sample No. | Sample Type | Cu* | Zn* | Pb* | Co* | Ni* | Ag* | Au# |
| Bjørnmyrgruva-1 | Dump | 253 | 102 | 7 | 238 | 141 | -.1 | 44.5 |
| ------------------ |
| Sample No. | As* | Cd* | Ba* | Mo* | Sn* | Sb* | Bi* | Se* | Ga* |
| Bjørnmyrgruva-1 | 18 | -.1 | 7896 | 2.50 | -1 | 1 | -0 | -0.50 | 5.40 |
| ------------------ |
| Sample No. | S% | V* | Fe% | Th* | U* | W* | Rb* | Sr* | Y* |
| Bjørnmyrgruva-1 | .20 | 372 | 35.86 | -0.20 | 0.80 | -1 | 2.6 | 450.2 | 25.1 |
| ------------------ |
| Sample No. | Zr* | Nb* | Ta* | Cs* | La* | Ce* | Pr* | Nd* | Sm* |
| Bjørnmyrgruva-1 | 26 | 0.90 | -0.10 | 0.40 | 7.70 | 13.50 | 2.12 | 10.50 | 3.09 |
| ------------------ |
| Sample No. | Eu* | Gd* | Tb* | Dy* | Ho* | Er* | Tm* | Yb* | Lu* |
| Bjørnmyrgruva-1 | 1.10 | 4.24 | 0.75 | 5.16 | 1.11 | 3.37 | 0.54 | 3.59 | 0.59 |
| ------------------ |
| Sample No. | Be* | P* | Hf* | Hg* | Tl* | ||||
| Bjørnmyrgruva-1 | 2 | 698 | 0.60 | -0 | -0 |
Oxide analyses |
( All values are in % ) |
| Sample No. | Sample Type | SiO2 | Al2O3 | TiO2 | Fe2O3 | MnO | MgO | CaO |
| Bjørnmyrgruva-1 | Dump | 19.09 | 4.21 | 0.34 | 51.27 | 13.79 | 0.58 | 2.78 |
| ------------------ |
| Sample No. | Na2O | K2O | P2O5 | Sum | |||||
| Bjørnmyrgruva-1 | 0.51 | 0.03 | 0.16 | 93.00 |
| The fact sheet was created on 19.05.2024 |
| Questions or comments regarding the fact sheet can be emailed to: ressursdatabaser@ngu.no |
| Copyright © 2024 Geological Survey of Norway |