Norsk versjon
	THE ORE DATABASE
	Occurence 5043 - 010 Bjørknesbekken
	(Object Id: 244) (Last updated: 04.05.2006)

Operations

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

Mineralization

	Era:	Paleozoic	Period:	Ordovician
	Genesis:	Volcex	Form:	Lens
	Main texture:	Banded	Min. distribution:	Massive (>50 % ore minerals)

Main grain size:

Fine grained (< 1 mm)

Main alteration:

Silicification

	Strike/Dip:	75 / 70	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

	Province:	Caledonides
	Geotec.unit:	Køli Nappe Complex
	Tectonic complex:	Gjersvik Nappe
	Igneous complex:

Group:

Gjersvik

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Quartz	Major mineral (>10%)
	Gangue mineral	Amphibole	Subordinate mineral (1-10%)
	Gangue mineral	Chlorite	Subordinate mineral (1-10%)
	Ore mineral	Pyrite	Major mineral (>10%)

Lithology:

	Relationship	Rock	Origin
	Wall rock	Greenstone	Extrusive Original rock :Basalt
			Metamorphic facies :Greenschist
	Wall rock	Doleritic greenstone	Intrusive Original rock :Dolerite
			Metamorphic facies :Greenschist

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Wall rock	Schistosity	Strike/Dip :66 / 60	Post-mineralisation ;...Effect :None
	Wall rock	Foliation	Strike/Dip :75 / 70	Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Forekomsten ligger i øvre del av granskogen, ca 500 m VSV for gården Nyheim, 25 m nord for bekken som renner forbi den samme gården. Det er dårlig med blotninger omkring skjerpet som ligger på en svært liten knaus, hvor det er foretatt mindre sprengningsarbeider. I bekken er sidestein godt blottet. Oftedahl (1958) omtaler tre skjerp i dette området, men bare ett ble funnet ved befaring i 1996. Mineraliseringen ligger rett sør for et gangkompleks som er kartlagt over Skorovassklumpen. Den består av en opptil 25 cm bred sone med massiv, finkornet svovelkis; vasskis. Den massive malmen er kun synlig tre meter langs strøket. Grønnsteinen er noe bleket i en 0.5-1 m bred sone rundt den massive kisen. Ingen forekomster er påvist på Bjørkneset, 1-1.5 km lengre østnordøst hvor registreringen tidligere er gjort i Bergarkivet. Prøvepunkt 1 er fra det område hvor kun spredte pyrittførende årer i grønnstein er observert.

Bibliography:

From NGU's Reference Archive:

Oftedahl, Christoffer , 1958

	Oversikt over Grongfeltets skjerp og malmforekomster.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.202;1-75 + fo pages

Abstract:

Ore occurences of the Grong area: In the period 1910-1918 a great number of ore occurences were discovered in the Grong area. The late state geologist Steinar Foslie mapped the area in the years 1922-1931. Foslie also mapped all claims and occurences and made special field investigations in a few cases. This book presents a survey of all occurences chiefly based on the field observations of Foslie. In addition the present author has done some field work in connection with the three large deposits, Joma, Skorovass, and Gjersvik. The map, Plate 1, shows the areal geology and the location of the occurrences, numbered from 1 to 131. the ore of the occurrences is chiefly pyrite. The larger occurrences also contain some chalcopyrite and sphalerite etc. and the smaller occurrences contain ither pure pyrite with some magnetite. The Joma deposit (No. 1), contains about 15.5 mill. tons of ore. The ore zone forms an arc and is situated within a thick series of greenstones (Fig. 1). The Skorovass mine (No. 2), contains about 7,5 mill. tons of ore. The deposit is situated in a greenstone complex (Fig. 7), and is immediately surrounded by asid tuffs of quartz keratophyric composition (Table 1).

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	NT0268.01	Dump	Sampler: Sandstad, J.S./...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite ore, fine grained, weakly banded. No. of registrated element analyses = 1
	NT0268.02	Dump	Sampler: Sandstad, J.S./...Stored: Løkken/...Size(kg): 2 Comment: Pyrite veins/dissemination, in fine grained, altered greenstone with dark grey spots. No. of registrated element analyses = 1

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

Name of Sample point: Bjørkneset

(Object Id: 597 10,00,01)

Location

County:

Trøndelag

Municipality:

Raarvihke (5043)

Map 1:50000:

Skorovatn (1824-2)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

East:

413082 m.

North:

7172899 m.

Longitude:

13.1790800

Latitude:

64.6697580

Show on map

Resource

	Resource Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Resource Subtype:	Sulphides
			Element(s):	Kis

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	LS91124	Bedrock	Sampler: Størseth, L.R. Comment: Pyrite vein in greenstone. 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 5043 - 010 Bjørknesbekken

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#
LS91124	Bedrock	173	82	2	269	34	.5	18.0
NT0268.01	Dump	45	77	57	21	28	1.1	57.0
NT0268.02	Dump	40	162	16	39	145	-.3	4.0

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Sample No.	Pt#	Pd#	Rh#	As*	Cd*	Ba*	Mo*	Sb*	Bi*
LS91124	1.0	1.0		14	.2	3	6.00	2	2
NT0268.01	-1.0	1.0	-1.0	81	.3	4	2.00	-2	-2
NT0268.02	-1.0	1.0	-1.0	25	1.8	19	7.00	-2	-2

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

Sample No.	S%	V*	Cr*	Mn*	Fe%	Th*	U*	W*	Sr*
LS91124	14.15	69	20	975	18.60	1.00	5.00	1	9.0
NT0268.01	37.31	25	12	63	14.63	-2.00	-5.00	-2	12.0
NT0268.02	3.11	185	252	539	7.33	-2.00	-5.00	-2	3.0

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

Sample No.	La*	B*
LS91124	2.00	2
NT0268.01	-1.00	6
NT0268.02	-1.00	4

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The fact sheet was created on 30.04.2024

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

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