Norsk versjon
	THE INDUSTRIAL MINERAL DATABASE
	Deposit Area 1836 - 312
	(Last updated 10.jan.2022)

Importance

Public:

Not Assessed (reg. 07.12.2015)

Economical:

Minor interest , (Confirmed 17.mar.2015 by Havard Gautneb)

Products

	Element/product	Crude ore grade or quality
	REFRAC	100%
	SLAGCO	100%

Operations

	From - To	Activity	Comments
	1996 - 1996	Sampling	Company/Institution :NGU

Mineralization

	Era:	Proterozoic	Period:
	Dating:		Method:
	Genesis:	Liquid magmatic	Form:	Lens
	Main texture:	Granoblastic	Min. distribution:	Irregular (scattered)

Main grain size:

Coarse grained (> 3 mm)

	Strike/Dip:		Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Proterozoic

Period:

	Province:	Caledonides
	Geotec.unit:
	Tectonic complex:
	Igneous complex:

Group:

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Not defined	Olivine	Major mineral (>10%)
	Not defined	Enstatite	Major mineral (>10%)
	Not defined	Serpentine	Major mineral (>10%)
	Not defined	Magnetite	Subordinate mineral (1-10%)
	Not defined	Spinel	Subordinate mineral (1-10%)
	Not defined	Talc	Accessory mineral (<1%)

Information(s) in free text format

Free text

Forekomsten ligger noen hundre meter syd for tettstedet Nord-Værnes. Her har vi en ca. 1,3 km lang og 350 m bred inhomogen ultramfisk bergart. En indre kjerne består av en delvis serpentinisert dunitt og en ytre randsone består av en hartzburgittisk bergart med svært grovkrystallinsk sammenvoksing som danner en såkalt jack-straw tekstur. To ultramafiske linser på 300x500 m og 200x300 m. Består av harzburgitt (enstatitt + olivin), dunitt (olivinstein) og serpentinitter. Dunitter utgjør anslagsvis 20-30 % av massivet. Dunittene består av opptil 90 % olivin, men det er usikkert hvor mye av denne som er serpentinisert. Deler av den er sterkt serpentinisert. Dunittene har en impregnasjon av spinell på 2-4 % (kromitt med høyt jerninnhold). Enkelte bånd på opptil 20 cm av spinell har ført til røskinger flere plasser i massivet. S. Olerud -94.

Photo(s) from the Deposit area:

Photo no. 1 showing Oversikts bilde" Photo no. 2 showing Nærbilde av Jack Straw tekstur" Photo no. 3 showing Prøvelokalitet"

Bibliography:

From NGU's Reference Archive:

Gautneb, Håvard , 1997

	Resultater fra regionale olivin- og serpentinundersøkelser i Norge 1996

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.97.043;60 pages

Gautneb, Håvard , 1996

	Oversikt over olivin- og serpentinittforekomster, registrert ved NGU

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.96.077;65 pages

Abstract:

Denne rapporten gir en oversikt over Norges olivin- og serpentinittforekomster samt en oversikt over NGUs tilhørende informasjon. Ved NGU er det registrert 70 olivin- og 80 serpentinittforekomster. Forekomstene er delt inn i følgende grupper 1) forekomster innenfor grunnfjellsområdene 2) forekomster innenfor den kaledonske fjellkjede. Sisnevnte er igjen delt i følgende grupper a) ultramafiske lag og linser b) høytemperatur ultramafiske intrusjoner c) ultramafiske xenolitter d) de såkalte "alpin-type" ultramafitter e) klast- iske serpentinitter. De aller fleste forekomstene tilhører gruppen av alpin- type ultramafitter, som nesten utelukkende omfatter ultramafitter som opprin- nelig har vært en del av ofiolitter. Rapporten gir en kort beskrivelse av de forekomstene som har data registrert ved NGU. I enkelte tilfeller er også detaljopplysninger presentert.

Bakke, Stig; Korneliussen, Are , 1986

	Jack-straw-textured olivines in some Norwegian metaperidotites.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.66 (4);271-276 pages

Abstract:

Jack-straw-textured olivines, which are elongate olivines of metamorphic origin, occur in complexly metamorphosed ultramafites within the Norwegian Caledonides. The ultramafic bodies are lenses enclosed within high-grade mica-shists or gneisses. In generally they consist of a dunitic core sur- rounded by massive olivine orthopyroxenite with a mantle of jack-straw-textured olivines in contact with the country rocks. The jack-straw olivines are elongate, radomly orientated platy crystals from 3 cm to 1 m long. They lie in a matrix of orthopyroxene, carbonate and minor tremolite. Field relations between various rock-types, including jack-straw textured olivine + carbonate + talc +/ bronzite veins, are well exposed at the Nordvernes ultramafic body, North Helgeland.

Karlsen, Tor Arne ; Gautneb, Håvard ; Lund, Bjørn , 1999

	Status-report on talc-prospecting in Helgeland, northern Norway.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.99.068;? pages

Abstract:

A prospecting programme for talc has been carried out in Helgeland. The results are both good and bad; a new talc deposit has been found in Kvanndalen, a few km west of Altermark. The deposit are exposed, and the size is not yet known, except that the maximum width is around 50 metres. To be able to use th ore, there must either be a market for the assemblage talc-breunnerit-olivine, or it must be possible to remove the olivine. A further deposit of interest occurs in Misvær. Otherwise, talc is rather uncommon in the numerous ultramafic lenses around the Høgtuva-, Sjona- and Svartisen windows. The ultramafic lenses are dominated by the metamorphic assemblage enstatite-anthophyllite-carbonate with or without olivine. It is concluded that the metamorphic grade has, in general, been too high in the western area and that possible pre-existing talc-carbonate assemblages have been altered to the minerals above. The deposit in Kvanndalen probably represent the margin of what can be termed the Altermark Talc Province. Only olivine has been included in the talc-carbonate assemblage, while bodies further to the west carry olivine, enstatite and anthophyllite.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	NGUAK96042	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96043	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96044	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96045	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96046	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96047	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96048	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96049	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96050	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96051	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUAK96052	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUHG96049	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUHG96050	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUHG96051	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1
	NGUHG96052	Bedrock	Comment :This is a dummy sample that does not excists. The assosciated analyses have been compiled from various published and unpublished reports No. of registrated oxide analyses = 1

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

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Analyse Results

from

Deposit Area 1836 - 312 Nord-Værnes

Oxide analyses

( All values are in % )

Sample No.	Sample Type	SiO2	Al2O3	TiO2	Fe2O3	MnO	MgO	CaO
NGUAK96042	Bedrock	46.30	0.38	0.00	8.40	0.13	40.70	0.78
NGUAK96043	Bedrock	42.60	0.45	0.00	9.30	0.16	46.30	0.07
NGUAK96044	Bedrock	42.40	0.34	0.00	9.70	0.10	46.70	0.05
NGUAK96045	Bedrock	46.10	3.34	0.00	6.80	0.06	41.60	0.07
NGUAK96046	Bedrock	43.00	0.43	0.00	8.70	0.10	46.80	0.04
NGUAK96047	Bedrock	41.60	0.36	0.00	10.30	0.13	46.20	0.05
NGUAK96048	Bedrock	41.70	0.35	0.00	10.30	0.14	47.00	0.11
NGUAK96049	Bedrock	50.70	0.40	0.00	8.20	0.12	38.40	0.25
NGUAK96050	Bedrock	48.20	0.34	0.00	8.30	0.11	40.40	0.15
NGUAK96051	Bedrock	23.00	3.20	0.00	25.00	0.30	30.00	0.04
NGUAK96052	Bedrock	43.50	0.45	0.00	8.90	0.09	46.30	0.07
NGUHG96049	Bedrock	41.90	0.27	0.00	8.60	0.12	48.20	0.12
NGUHG96050	Bedrock	41.80	0.39	0.00	9.00	0.13	47.40	0.09
NGUHG96051	Bedrock	40.90	0.35	0.00	7.70	0.11	44.70	0.06
NGUHG96052	Bedrock	41.00	0.21	0.00	7.90	0.14	50.00	0.12

------------------

Sample No.	Na2O	K2O	P2O5	Loss	Sum
NGUAK96042	0.01	0.01	0.00	2.74	99.00
NGUAK96043	0.00	0.00	0.00	0.96	100.00
NGUAK96044	0.00	0.00	0.00	0.51	100.00
NGUAK96045	0.00	0.00	0.00	2.02	100.00
NGUAK96046	0.00	0.00	0.00	0.60	100.00
NGUAK96047	0.00	0.00	0.00	1.16	100.00
NGUAK96048	0.01	0.00	0.00	0.31	100.00
NGUAK96049	0.00	0.00	0.00	0.56	99.00
NGUAK96050	0.00	0.00	0.00	2.18	100.00
NGUAK96051	0.08	0.00	0.00	0.55	82.00
NGUAK96052	0.00	0.00	0.00	0.22	100.00
NGUHG96049	0.02	0.00	0.00	0.28	100.00
NGUHG96050	0.02	0.00	0.00	0.57	99.00
NGUHG96051	0.00	0.00	0.00	5.78	100.00
NGUHG96052	0.00	0.00	0.00	0.53	100.00

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The fact sheet was created on 17.05.2024

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

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