Fact Sheet for Deposit Area 1740

					Norsk versjon
	THE ORE DATABASE
	Deposit Area 1740 - 009
	(Last updated 16.mai.2006)

Name of Deposit Area : Grønndalselv

(Object Id : 1740,009,00,00)

Location

County :

Nord-Trøndelag (17)

Municipality :

Namsskogan (1740)

Map 1:50000:

Skorovatn (1824-2)

Map 1:250000:

Grong

Marking point:

Longitude:

12.9182110

Latitude:

64.6530310

EU89-UTM Zone 33

(Coordinates IS confirmed)

X-coord:

400572 m.

Y-coord:

7171419 m.

Commodity

	Main Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Sub Type:	Copper
			Element(s):	Cu Kis

Production

Activity:	Pitting	Reserves:
Prod. method:		Production:
Prod. status:		Volume of dump:	2 m3

Importance

Public: Little Importance (reg. 18.02.2015)

Economical: Minor interest

Operations

From - To Activity Comments

1969 - 1969 Geophysics Company/Institution :NGU

1970 - 1970 Geophysics Company/Institution :NGU

1974 - 1975 Geophysics Company/Institution :Grong Gruber

1977 - 1977 Geology Company/Institution :Grong Gruber A/S

1978 - 1978 Geophysics Company/Institution :Grong Gruber A/S

1981 - 1981 Geophysics Company/Institution :Grong Gruber A/S

1984 - 1984 Geophysics Company/Institution :Grong Gruber A/S

1994 - 1994 Geology Company/Institution :NGU

1996 - 1996 Sampling Company/Institution :NGU

Mineralization

Era: Paleozoic Period: Ordovician

Dating: Method:

Genesis: Volcex Form: Layer

Main texture: Structureless Min. distribution: Disseminated (<20 % ore minerals)

Main grain size: Medium grained (1-3 mm) Main alteration: Silicification

Strike/Dip: 245 / 60 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 Mica Subordinate mineral (1-10%)

Gangue mineral Plagioclase Subordinate mineral (1-10%)

Ore mineral Pyrite Major mineral (>10%)

Ore mineral Pyrrhotite Major mineral (>10%)

Ore mineral Chalcopyrite Subordinate mineral (1-10%)

Ore mineral Sphalerite Accessory mineral (<1%)

Lithology:

Relationship Rock Origin

Host rock Quartz kerophyre Extrusive
Original rock :Rhyodacite

Metamorphic facies :Greenschist

Wall rock Greenstone Extrusive
Original rock :Basalt

Metamorphic facies :Greenschist

Structures

Location: Type: Orientation(360 gr.): Relation to min.:

Host rock Fold axis Strike/Dip :66 / 50 Post-mineralisation ;...Effect :Modifies

Wall rock Foliation Strike/Dip :245 / 60 Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Forekomsten ligger ca. 100 m NØ for Grønndalselva, ca. 800 m før dennes samløp med Skorovas-elva. Mineraliseringen ligger i amfibolittisk grønnstein i veksling med keratofyr og intermediære vulkanitter. Malmsonen stryker NØ/SV med steilt fall mot NV. Den er opptil 1 m mektig sentralt i skjerpet. Denne fortykning skyldes foldning og den kiler raskt ut langs strøket etter få meter. Mineraliseringen består av disseminert magnetkis, svovelkis og kobberkis i kvartsrik bergart, antatt silifisert keratofyr. I det sørøstligste skjerpet dominerer felsisk metavulkanitt. Ifølge geofysiske målinger har forekomsten ubetydelig utstrekning.

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

NT0259.01 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Pyrrhotite-pyrite-chalcopyrite disseminations., moderate-strong, fine to medium grained, partly veinlets in greywhite-greygreen quartz rich felsic metavulcanite, few chlorite lenses.

No. of registrated element analyses = 1

NT0259.02 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Pyrrhotite-pyrite-chalcopyrite, semi-massive to strong disseminations in greywhite, fine grained, quartzitic/cherty rock. ('rich ore')

No. of registrated element analyses = 1

NT0259.03 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Pyrrhotite-pyrite-chalcopyrite disseminations, weak, fine grained, in chlorite rich rock. (wall rock)

No. of registrated element analyses = 1

NT0259.04 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Pyrrhotite-pyrite-chalcopyrite disseminations, fine grained in quartz rich rock.

No. of registrated element analyses = 1

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

Name of Locality : Grønndalselv Ø

(Object Id : 1740,009,01,00)

Location

County : Nord-Trøndelag (17) Municipality : Namsskogan (1740)

Map 1:50000: Skorovatn (1824-2) Map 1:250000: Grong

Marking point: Longitude: 12.9186570 Latitude: 64.6526780

EU89-UTM Zone 33 (Coordinates IS confirmed)

X-coord: 400592 m. Y-coord: 7171379 m.

Commodity

Main Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Sub Type: Copper

Element(s): Cu Kis

Production

Activity: Pitting Reserves:

Prod. method: Production:

Prod. status: Volume of dump:

Fieldsamples

Sample No. Sample type Miscellanrous

NT0259.05 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Stron pyrite-sphalerite-chalcopyrite disseminations, fine grained., partly chalcopyrite veinlets, ligth sphalerite, in fine grained, grey-ligth grey, quartz rich rock.

No. of registrated element analyses = 1

NT0259.06 Dump

Sampler :Sandstad, J.S./...Stored :Løkken/...Size(kg) :2

Comment :Weak pyrite+chalcopyrite disseminations, fine grained, in fine grained, greyish white, laminated quartz keratophyre.

No. of registrated element analyses = 1

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

Analyse Results

from

Deposit Area 1740 - 009 Grønndalselv

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#

NT0259.01 Dump 2076 196 11 49 93 .9 12.0

NT0259.02 Dump 3624 334 21 80 182 1.5 14.0

NT0259.03 Dump 578 637 13 78 53 -.3 11.0

NT0259.04 Dump 1742 300 15 56 108 .7 8.0

NT0259.05 Dump 4678 64445 677 3 10 10.2 142.0

NT0259.06 Dump 86 261 181 2 2 1.3 10.0

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

Sample No. Pt# Pd# Rh# As* Cd* Ba* Mo* Sb* Bi*

NT0259.01 -1.0 -1.0 -1.0 -2 -.2 2 5.00 -2 5

NT0259.02 -1.0 4.0 -1.0 2 -.2 5 -1.00 -2 -2

NT0259.03 2.0 2.0 -1.0 3 .7 3 12.00 -2 -2

NT0259.04 -1.0 1.0 -1.0 2 -.2 4 3.00 -2 6

NT0259.05 -1.0 1.0 -1.0 -2 234.8 12 53.00 2 8

NT0259.06 -1.0 3.0 1.0 -2 .4 27 -1.00 -2 -2

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

Sample No. S% V* Cr* Mn* Fe% Th* U* W* Sr*

NT0259.01 5.99 12 8 404 10.26 -2.00 -5.00 -2 3.0

NT0259.02 9.80 27 16 1124 16.91 -2.00 -5.00 -2 4.0

NT0259.03 4.81 105 262 2844 11.12 -2.00 -5.00 -2 4.0

NT0259.04 6.78 27 14 860 10.38 -2.00 -5.00 -2 3.0

NT0259.05 7.25 11 3 304 6.39 -2.00 -5.00 30 7.0

NT0259.06 1.22 5 1 660 2.45 5.00 -5.00 -2 9.0

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

Sample No. La* B*

NT0259.01 3.00 -3

NT0259.02 6.00 -3

NT0259.03 2.00 -3

NT0259.04 4.00 -3

NT0259.05 4.00 -3

NT0259.06 11.00 -3

From - To	Activity	Comments
1969 - 1969	Geophysics	Company/Institution :NGU
1970 - 1970	Geophysics	Company/Institution :NGU
1974 - 1975	Geophysics	Company/Institution :Grong Gruber
1977 - 1977	Geology	Company/Institution :Grong Gruber A/S
1978 - 1978	Geophysics	Company/Institution :Grong Gruber A/S
1981 - 1981	Geophysics	Company/Institution :Grong Gruber A/S
1984 - 1984	Geophysics	Company/Institution :Grong Gruber A/S
1994 - 1994	Geology	Company/Institution :NGU
1996 - 1996	Sampling	Company/Institution :NGU

Era:	Paleozoic	Period:	Ordovician
Dating:		Method:
Genesis:	Volcex	Form:	Layer
Main texture:	Structureless	Min. distribution:	Disseminated (<20 % ore minerals)

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

Relationship	Mineral	Amount
Gangue mineral	Quartz	Major mineral (>10%)
Gangue mineral	Amphibole	Subordinate mineral (1-10%)
Gangue mineral	Mica	Subordinate mineral (1-10%)
Gangue mineral	Plagioclase	Subordinate mineral (1-10%)
Ore mineral	Pyrite	Major mineral (>10%)
Ore mineral	Pyrrhotite	Major mineral (>10%)
Ore mineral	Chalcopyrite	Subordinate mineral (1-10%)
Ore mineral	Sphalerite	Accessory mineral (<1%)

Relationship	Rock	Origin
Host rock	Quartz kerophyre	Extrusive Original rock :Rhyodacite
		Metamorphic facies :Greenschist
Wall rock	Greenstone	Extrusive Original rock :Basalt
		Metamorphic facies :Greenschist

Location:	Type:	Orientation(360 gr.):	Relation to min.:
Host rock	Fold axis	Strike/Dip :66 / 50	Post-mineralisation ;...Effect :Modifies
Wall rock	Foliation	Strike/Dip :245 / 60	Post-mineralisation ;...Effect :Modifies

Sample No.	Sample Type	Cu*	Zn*	Pb*	Co*	Ni*	Ag*	Au#
NT0259.01	Dump	2076	196	11	49	93	.9	12.0
NT0259.02	Dump	3624	334	21	80	182	1.5	14.0
NT0259.03	Dump	578	637	13	78	53	-.3	11.0
NT0259.04	Dump	1742	300	15	56	108	.7	8.0
NT0259.05	Dump	4678	64445	677	3	10	10.2	142.0
NT0259.06	Dump	86	261	181	2	2	1.3	10.0

Sample No.	Pt#	Pd#	Rh#	As*	Cd*	Ba*	Mo*	Sb*	Bi*
NT0259.01	-1.0	-1.0	-1.0	-2	-.2	2	5.00	-2	5
NT0259.02	-1.0	4.0	-1.0	2	-.2	5	-1.00	-2	-2
NT0259.03	2.0	2.0	-1.0	3	.7	3	12.00	-2	-2
NT0259.04	-1.0	1.0	-1.0	2	-.2	4	3.00	-2	6
NT0259.05	-1.0	1.0	-1.0	-2	234.8	12	53.00	2	8
NT0259.06	-1.0	3.0	1.0	-2	.4	27	-1.00	-2	-2

Sample No.	S%	V*	Cr*	Mn*	Fe%	Th*	U*	W*	Sr*
NT0259.01	5.99	12	8	404	10.26	-2.00	-5.00	-2	3.0
NT0259.02	9.80	27	16	1124	16.91	-2.00	-5.00	-2	4.0
NT0259.03	4.81	105	262	2844	11.12	-2.00	-5.00	-2	4.0
NT0259.04	6.78	27	14	860	10.38	-2.00	-5.00	-2	3.0
NT0259.05	7.25	11	3	304	6.39	-2.00	-5.00	30	7.0
NT0259.06	1.22	5	1	660	2.45	5.00	-5.00	-2	9.0