Norsk versjon
THE ORE DATABASE
Occurence 5044 - 009 Grønndalselv
(Object Id: 238)
(Last updated: 16.05.2006)

Location
County: Trøndelag Municipality: Namsskogan (5044)
Map 1:50000: Skorovatn (1824-2) Map 1:250000: Grong
Coordinate system: EU89-UTM Zone 33
East: 400572 m. North: 7171419 m.
Longitude: 12.9182110 Latitude: 64.6530310
Show on map

Resource
Resource Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Resource Subtype: Copper
Element(s): Cu Kis
Importance
Raw material meaning: Little Importance (reg. 18.02.2015)

Resources and production
Activity: Pitting Reserves:
Operating method: Historical production:


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
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: 469 9,01,00)

Location
County: Trøndelag Municipality: Namsskogan (5044)
Map 1:50000: Skorovatn (1824-2) Map 1:250000: Grong
Coordinate system: EU89-UTM Zone 33
East: 400592 m. North: 7171379 m.
Longitude: 12.9186570 Latitude: 64.6526780
Show on map

Resource
Resource Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Resource Subtype: Copper
Element(s): Cu Kis
Resources and production
Activity: Pitting Reserves:
Operating method: Historical production:


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 5044 - 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


The fact sheet was created on 07.05.2024

Questions or comments regarding the fact sheet can be emailed to:
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