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	THE ORE DATABASE
	Occurence 4034 - 060 Kroksmyr
	(Object Id: 5468) (Last updated: 28.03.2020)

Operations

	From - To	Activity	Comments
	1844 - 1844	Test mining
	2006 - 2006	Sampling	Company/Institution :NGU

Mineralization

	Era:	Proterozoic	Period:	Mesoproterozoic
	Genesis:	Metamorphic formation	Form:	Lens
	Main texture:	Fracture filling	Min. distribution:	Irregular (scattered)

Main grain size:

Fine grained (< 1 mm)

Main alteration:

Carbonatisation

	Strike/Dip:	230 / 50	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Proterozoic

Period:

Mesoproterozoic

	Province:	South Norwegian Basement Province
	Geotec.unit:	Telemark Supergroup
	Tectonic complex:
	Igneous complex:

Group:

Høydalsmo group

Formation:

Morgedal formation

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Amphibole	Major mineral (>10%)
	Gangue mineral	Carbonate	Major mineral (>10%)
	Gangue mineral	Quartz	Major mineral (>10%)
	Ore mineral	Bornite	Major mineral (>10%)
	Ore mineral	Covellite	Accessory mineral (<1%)

Lithology:

	Relationship	Rock	Origin
	Host rock	Amphibolite	Extrusive Original rock :Basalt
			Metamorphic facies :Amphibolite
	Wall rock	Porphyric quartz-feldspar rock	Extrusive Original rock :Rhyodacite
			Metamorphic facies :Amphibolite

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Wall rock	Foliation	Strike/Dip :247 / 80	Syn-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Bomveien fra Tveitegrendi nordvest for Kviteseid følges fram til Finneroi seter. En sti går derfra nordvestover mot forekomsten som ligger i en sørvendt brattskråning nord for ei myr. Den ligger 30 m øst for en bekk som renner ned i vestenden av myra. En 9 m lang dagskjæring med retning 335º fortsetter som en kort stoll, ca. 7 m, inn til en skrå dagskjæring med retning 60º og lengde 10-12 m. Det var ordinær drift i 1844 (Dons 1963). I den skrå dagskjæringen dominerer finkornet, strukturløs amfibolitt. Malmsona er opptil 0,5 m bred og består av aggregater, strenger og disseminasjon av bornitt i karbonatisert amfibolitt som fører uregelmessige kvarts- og karbonatårer og linser, opptil 15 cm brede. De rikeste kobbermineraliseringene opptrer i karbonatisert amfibolitt med hyppig små karbonat-kvarts linser. I dagskjæringa utenfor stollen finnes porfyrisk, grå metavulkanitt. Forekomsten kan være syngenetisk dannet med senere mindre remobilisering under deformasjonen. Den er imidlertid for liten til å være av økonomisk interesse i dag.

Bibliography:

From NGU's Reference Archive:

Dons, Johannes A. , 1963

	De prekambriske bergarter i Telemark, I. Gruber og skjerp innen gradeteigkart E36V Kviteseid.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.216;1-80 pages

Abstract:

Approximately 115 mines and claims have been examined in the years 1941-1961 during regional geological mapping of the Kviteseid quadrangle. The map area covers a part of the "Thelemark-Sætersdal ore province" established by prof. J.H.L. Vogt in 1886. The oldest mine in the area, opened in the year 1524, was worked for silver bearing chalcopyrite and bornite. Other mines have been worked for gold, native copper and silver, molybdenite, galena, arsenopyrite, bismuthinite. All the mines have long since been abandoned and most of the surface workings are overgrown and difficult to find. The 15 native copper and silver deposits (which also contain vanadium minerals) form a separate group. They are all situated along the contact between a sandstone and an overlying basalt, the ore being confined to the sandstone. Most of the other deposits are of Quartz vein type. In quartzites which cover the greatest part of the map area, most of the quartz veins are barren. The great abundance of ore minerals in quartz veins in basic lavas and basic sills may be due to favourable pH conditions in these rocks. The galena deposits are found within a limited area close to a penetrating granite. The ore mineral paragenese in some of the deposits may have been formed under hypothermal to mesothermal conditions whereas other possibly originated at lower temperatures.

Marstrander, H.

	Beskrivelse av gruber og skjerp i Kviteseid i Telemark.

;Norges geologiske undersøkelse;FAGRAPPORT;Bergarkivet; No.BA 2647;35 pages

	Abstract:
	Følgende forekomster er malmgeologisk beskrevet: Finnekos, Langmyr, Bjørnbas, Johnsli, Sølvbergsli, Bjørgustøl, Åneroe, Toråsdækkan, Byggstøl, Lintjern, Raubergmutern, Myran, Skolteberg, Fløta, Dal (Lundevassdal), Haugen, Bygland, Soli, kleiv og Kroksmyr.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	TE0081.01	Dump	Sampler: J.S. Sandstad/...Stored: L¿kken/...Size(kg): 2 Comment: Bornite dissemination/veinlets parallel foliation in carbonatised amphibolite No. of registrated element analyses = 1
	TE0081.02	Dump	Sampler: J.S. Sandstad/...Stored: L¿kken/...Size(kg): 2 Comment: Bornite, very rich, aggregates in altered amphibolite with carbonate-quartz lenses No. of registrated element analyses = 1

NB! All analyse values are shown at the end of the printout.:

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Analyse Results

from

Deposit Area 4034 - 060 Kroksmyr

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#
TE0081.01	Dump	78340	-100	-100	10	30	366.0	140.0
TE0081.02	Dump	110170	-100	-100	10	20	403.0	100.0

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Sample No.	As*	Cd*	Mo*	Sb*	Bi*	Cr*	Mn*	Fe%	W*
TE0081.01	-100	-10.0	10.00	10	-100	20	1000	2.75	-10
TE0081.02	-100	-10.0	20.00	-10	-100	10	800	1.98	-10

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Sample No.	Sr*	P*	Ca*
TE0081.01	70.0	0	3
TE0081.02	50.0	0	3

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The fact sheet was created on 20.04.2024

Questions or comments regarding the fact sheet can be emailed to: ressursdatabaser@ngu.no

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