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	THE ORE DATABASE
	Deposit 5045 - 010 Skiftesmyr
	(Object Id: 202) (Last updated: 14.03.2024)

Products

	Element/product	Crude ore grade or quality	Reg. date
	Ag	2.5 ppm	14.03.2024
	Cu	1.0 %	26.05.1997
	Zn	1.5 %	26.05.1997

Operations

	From - To	Activity	Comments
	1910 - 1912	Pitting	Company/Institution :Unknown
	1970 - 1970	Geology	Company/Institution :NGU
	1970 - 1970	Geochemistry	Company/Institution :NGU
	1970 - 1970	Geophysics	Company/Institution :NGU
	1973 - 1975	Geophysics	Company/Institution :NGU
	1973 - 1975	Core drilling	Company/Institution :Grong Gruber A/S
	1974 - 1974	Geology	Company/Institution :Grong Gruber A/S
	1978 - 1979	Core drilling	Company/Institution :Grong Gruber A/S
	1990 - 1991	Sampling	Company/Institution :NTH/NGU
	1990 - 1993	Core drilling	Company/Institution :Norsulfid A/S
	1991 - 1992	Geophysics	Company/Institution :Norsulfid A/S
	1991 - 1992	Geology	Company/Institution :Norsulfid A/S
	1996 - 1996	Geochemistry	Company/Institution :Geologiske Tjenester A/S
	1996 - 1996	Geology	Company/Institution :Geologiske Tjenester A/S
	1996 - 1996	Sampling	Company/Institution :NGU

Mineralization

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

Main grain size:

Medium grained (1-3 mm)

Main alteration:

Chloritisation

	Strike/Dip:	230 / 80	Direction:	310
			Plunge:	60

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

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

Group:

Gjersvik

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Calcite	Major mineral (>10%)
	Gangue mineral	Quartz	Major mineral (>10%)
	Gangue mineral	Chlorite	Subordinate mineral (1-10%)
	Gangue mineral	Sericite	Subordinate mineral (1-10%)
	Ore mineral	Pyrite	Major mineral (>10%)
	Ore mineral	Pyrrhotite	Subordinate mineral (1-10%)
	Ore mineral	Chalcopyrite	Subordinate mineral (1-10%)
	Ore mineral	Sphalerite	Subordinate mineral (1-10%)
	Ore mineral	Magnetite	Subordinate mineral (1-10%)
	Ore mineral	Galena	Accessory mineral (<1%)

Lithology:

	Relationship	Rock	Origin
	Wall rock	Greenstone	Extrusive Original rock :Basalt
			Metamorphic facies :Greenschist
	Wall rock	Magnetite bearing quartzite	Sedimentary Original rock :Exhalite
			Metamorphic facies :Greenschist
	Wall rock	Quartz-sericite(-albite) rock	Extrusive Original rock :Basalt
			Metamorphic facies :Greenschist
	Wall rock	Keratophyre	Extrusive Original rock :Rhyodacite
			Metamorphic facies :Greenschist

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Wall rock	Crenulation cleavage	Strike/Dip :20 / 60	Post-mineralisation ;...Effect :Modifies
	Wall rock	Fold axis	Dir./Plunge :310 / 60	Post-mineralisation ;...Effect :Modifies
	Wall rock	Mineral lineation	Dir./Plunge :310 / 60	Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Abstract

Massive sulphides at Skiftesmyr consists mainly of pyritic Zn-Cu ore which occurs as layers or a continuous series of ore lenses forming a 2–20 m thick, plate-like orebody overlain by lenses of magnetite-bearing metachert. The main gangue minerals are quartz, chlorite and calcite. Both foot-wall and hanging-wall rocks are strongly affected by quartz-sericitic, albitic or chloritic alteration with variable amounts of sulphide veins and dissemination. The orebody shows a marked lateral zonation, with Cu-dominated ore concentrated to the eastern and upper levels of the orebody and Zn-rich ore to the western parts and at depth. Skiftesmyr holds a NI 43-101 compliant indicated resource of 3.51 Mt @ 1.0% Cu, 1.5% Zn, 0.1 g/t Au and 2.5 g/t Ag at a 0.5% lower block Cu cut-off and a inferred resource of 0.57 Mt @ 1% Cu, 1.6% Zn, 0.1 g/t Au and 2.7 g/t Ag at the same lower block Cu cut-off of 0.5% (METPRO 2013).

Free text

The Skiftesmyr deposit occur in the Møklevatnet area at the SW corner of the Grong District, c. 20-30 km east of the Grong community centre. The Skiftesmyr deposit occurs at roughly the same stratigraphic level as the Skorovass and Gjersvik deposits to the north. These two deposits are overlain by a pronounced layer of felsic volcanites. The Skiftesmyr deposit occurs in a slightly different environment and is overlain by a thicker sequence of mixed felsic/mafic tuffs and/or volcaniclastics which grades upwards into more mafic dominated tuffs and massive to pillowed lava flows. These rocks are metamorphosed under upper greenschist to lower amphibolite facies conditions. Regionally, the rocks show varying degrees of shearing being for the most part moderately foliated, and in some areas volcanic structures and textures are preserved. On approaching the massive ore zone, however, the country rocks become extremly sheared. The orebody The orebody at Skiftesmyr consists mainly of Zn-Cu rich massive pyritic ore that occurs as thin layers or as a continuous series of ore lenses forming a relatively thin, plate-like orebody. The thickness of the ore zone is typically 4-6m, but varies between 2-20m. The massive ore contains many fragments of country rock near its contact with the host rock, especially within the upper and eastern parts of the orebody. These fragments appear to be remnants of fold hinges that have been ripped apart and now occur as loose fragments, floating within the strongly sheared orebody. The orebody consists dominantly of massive sulphide layers and lenses enclosed within a quartz-sericite, albite and chlorite rich schistose country rocks that contain variable quantities of disseminated and veined sulphides, dominantly pyrite. Minor quantities of chalcopyrite (cpy) and sphalerite (sl) are also present within these altered and sheared rocks, cpy being mostly confined to the darker chlorite rich rocks and sl in the pale, quartz-sericite and albite rich rocks. The massive ore is dominantly pyritic with varying subordinate quantities of cpy and sl and minor amounts of pyrrhotite (po). The Ag and Au mineralogy at Skiftesmyr has to date not been studied and the distribution of these precious metals within the orebody is little known because of the sparse amount of analytical data presently available. The main gangue minerals are quartz, chlorite and calcite. Copper and zinc show a clear zonal distribution within the massive pyrite orebody. The Cu rich ore dominates within the eastern and upper levels of the orebody and Zn rich ore is consentrated in the western part and at depth in the orebody. The deposit is open at depth and towards the west, where the orebody also becomes distinctly thinner. The massive pyritic ore at Skiftesmyr is a compact, homogeneous ore type of medium-grained size, generally in the range of 1-5mm. Although no detailed mineralogical study has been done here, the individual pyrite grains appear to be granular in nature having well developed grain boundaries and are relatively clean with few sulphide inclusions. Chalcopyrite and sphalerite usually form grains at the boundaries between the larger pyrite grains. Pyrrhotite occurs only as a minor constituent within the massive ore and is found mainly along shear planes and late fractures that cut across the pyrite grain boundaries. Thus, mineral separation of the Skiftesmyr ore should give relatively clean products and should not cause great problems. Host rocks The massive orebody is enclosed in intensely altered rocks that adjacent to the orebody are strongly sheared and schistose. On the south side of the orebody, the footwall rocks are dominated by pale coloured, quartz-sericite and albite rich rock carrying large quantities of disseminated pyrite and quartz-pyrite veins. These grade into darker, chlorite rich rocks that contain minor quantities of pyrrhotite. The altered rocks are arranged in a zonal pattern around the orebody. Quartz-sericite rich rocks occur adjacent to the orebody and grade outwards away from the massive orebody into albite- and chlorite-rick rocks. Further into the footwall, the chlorite-rich rocks grade into more normal chloritic greenstones rich in epidote and carbonate and with minor disseminations of po and py. Volcanic structures such as pillows are present in these rocks. Near the surface, within the immediate hanging wall to the orebody, the country rocks are visibly paler in colour, harder and are richer in quartz-albite with less quartz-sericite and chlorite. Deeper within the orebody, along the hanging wall, the rocks are more schistose and become richer in quartz-sericite and chlorite. Along the western edges of the Storedalen valley, to the NE of the main showing, pale coloured quartz-sericite and albite rich rocks occur that contain zones rich in pyrite disseminations and quartz-pyrite veining surrounded by darker chlorite rich rocks with only minor pyrite. These intensly altered and strongly sulphide impregnated rocks are thought to represent the feeder zone to the massive sulphide ores at Skiftesmyr. This N-NE trending zone of strong pyrite disseminated rocks corresponds with a strong EM anomaly found in the overburden covered lowland area to the N of the main showing. This anomaly can be traced for several km to the NE. North of the surface expression to the massive ore horizons, the hanging wall rocks to the orebody consists of a of sequence of variably layered, massive felsic volcanites and/or intrusive sills (?) that are interlayered with fine-laminated felsic to mafic tuffs or tuffites? Some of these felsic layers show clearly turbiditic/ volcaniclastic textures (fine- to coarse-grained beds) and soft sediment slumping folds are observed. The quartz and albite rich felsic layers are generally variably magnetic in nature. Some extremely magnetic layers have been observed in drill core. The high magnetite contents in certain quartz rich layers may be derived from reworking of earlier magnetite bearing felsic volcanic rocks. This layered felsic tuff/ volcaniclastic sequense grades upwards into mafic dominated tuffs with minor felsic layers, which in turn grades stratigraphically upwards into a mafic massive and pillowed flow sequence. The layered felsic-mafic tuffite/volcaniclastic and overlying mafic lava unit that lies to the north of the orezone is interpreted to be younger than the massive sulphide mineralization and associated altered hanging wall and footwall mafic volcanic rocks that host the massive orebody at Skiftesmyr. On surface, near the main showing, massive sulphide ore is in contact with irregular lenses (overlain by), bands and fragments of magnetite bearing quartzites (recrystallized chert), which are interpreted as silica rich exhalites. Magnetite-bearing chert, with minor amounts of po and py, occur as layers and lenses of varying thickness and extent, at the contact between the two main rock units at Skiftesmyr. In simplest terms, the altered mafic volcanic complex forms the stratigraphic footwall and the mixed felsic/mafic tuff-volcaniclastic complex forms the hanging wall to the massive orebody. Late, feldspar-phyric felsic and pale green gabbroid dykes are found cutting the ore zone and the overlying tuff/volcaniclastic complex. Structures The orebody occurs partially within a major shear zone. The massive pyritic ore, containing numerous fragments of folded country rocks, occurs as parallel ore layers and lenses within what appears to be a major shear zone along the hanging wall side, throughout the whole length of the orebody. This is well demonstrated in most vertical sections. The shear zone appears to be an early structure and the ore zone plunges steeply to the NW within this structure. The distribution of Cu- and Zn-rich zones within the orebody and the ore thickness also appears to plunge in a NW direction, suggesting that they also may be related to later folding and shearing deformation. The surface geological map over Skiftesmyr shows that the area has been folded into a major open flexure. The rocks to the NE and E of the main showing trend to the north and dip steeply to the west and rocks within the ore zone and to the west, trend roughly E-W and dip steeply (60-65°) to the north. This is a late crenulation type fold having NE steeply plunging fold axes. Ore reserves and production plans The earliest ore reserve calculation quoted for the Skiftesmyr deposit was carried out in 1977 by Grong Gruber A/S and gave a geological ore reserve of 3.5M tonnes grading 1.16% Cu and 1.79% Zn (Grong Gruber A/S company files). Later drilling has not changed to any degree this figure from 1977. In 1992, Norsulfid A/S presented an ore reserve calculations for the Skiftesmyr deposit which included all drilling done on the deposit up to 1992 ( Norsulfid A/S company report to the Mining Commission, BV 2882). Plans for both underground and an open pit mining was also presented in 1992 (Norsulfid A/S company report to the Mining Commission, BV 2883 and 2885): 1) cut-off 1% Cu equivalent: total 2 746 470 tonnes grading 1.23% Cu, 1.86% Zn, 11.37 ppm Ag, 0.35 ppm Au and 37.52% S. The calculated ore zone has a strike length of 400m and a vertical length of 400m. The thickness of the ore zone varies between 2-21m. 2) cut-off 2% Cu equivalent: total 1 759 417 tonnes grading 1.38% Cu, 2.13% Zn, 12.99 ppm Ag and 0.37 ppm Au. 3) According to underground mining plans reported in 1992 by Norsulfid A/S (report BV 2883), a total of 2 684 000 tonnes of ore was planned to be taken out (cut off 1% Cu equivalents), grading 1.08% Cu, 1.63% Zn, 8.65 ppm Ag, 0.31 ppm Au and 34.6% S. The reduced tonnage and grades quoted here results from ore being tied up in pillars and from waste rock dilution. History The original discovery was made around the turn of the century about the same time as the rest of the discoveries in the Grong district. Early activities in the area (1910-12) included trenching and sampling of the Main (Hoved), Middle (Midtre), Western (Vestre) and Southwest showing along the main ore zone at Skiftesmyr, and on the three showings referred to as the Stordalen showings (Stordalen vest, Stordalen øst and Stordalen nord, respectively). The first mention of the Skiftesmyr showings in the literature dates back to Henriksen (1914) and Bryn (1917). Modern exploration started first in 1970 and continued until present in two periods of increased activity, 1970-79 by Grong Gruber A/S and 1991-93 by Norsulfid A/S. Norwegian Gold Exploration (Braddick Resources, Toronto, Canada) took over the claims to the Skiftesmyr deposit in 1996 and did some limited exploration in the area which included a large soil sampling survey (analysed for Cu, Zn, Ag, Au and As) over the Skiftesmyr and Stordalen showings. Braddick Resources is currently doing a feasibility survey (1996) of the Skiftesmyr and Godejord deposits to see if it is possible to start production on these two deposits simultaneously. Godejord is situated approximately 3-4 km to the south-west of Skiftesmyr. Geology: The following geological mapping has been done on the Skiftesmyr deposit. 1) K. Langley mapped the surface exposures at Skiftesmyr for Grong Gruber A/S in 1974 (outcrop rock type map, with little geological interpretation). 2) M. Heim (1993) regional map and interpretation of the southwest Grong District, including detailed regional interpretation over the Skiftesmyr area. Mapped was done for NGU on a contract from Norsulfid A/S. 3) Detailed surface geological map (Reinsbakken 1991-92) and interpretation of the drill-hole data in eight N-S vertical sections for construction of a 3-D model of the Skiftesmyr deposit (Reinsbakken, 1992) for Norsulfid A/S in connection with ore reserve calculation by Norsulfid in 1992 (Lideman, 1992) and for a feasibility study in 1996 done for Geologiske Tjenester A/S, Oslo, by Braddick Resources, Toronto, Canada. Geophysics: 1) TURAM EM measurements over the Skiftesmyr showings done in 1973-74 for Grong Gruber A/S by NGU (Sakshaug, 1974, 1975 and 1977). TURAM-EM measurements in 1991 over the eastern part of Skiftesmyr, the Stordalen and to the area east of Stordalen for Norsulfid A/S by H. Elvebakk, PTS-NTH. 2) IP (Eidsvik, 1975) and CP (Eidsvik, 1975 and Kihle, 1976 and 1978) measurements done on the Skiftesmyr and Stordalen north showings for Grong Gruber A/S and in 1991 on some drill holes along western Stordalen (Elvebakk, 1991) for NorsulfidA/S. 3) Modern helicopter measurements (mag., EM, VLF and radiometrics) were flown over the area, on E-W 200m line spacings, by NGU in 1990 (Rønning, Kihle, Blokkum and Håbrekke, 1990) and again in 1995 on N-S lines (Smethhurst and Skilbrei, 1992). 4) In 1992, Outokumpu OY, Finland did a detailed, digital Slingram-EM and mag. survey over the Skiftesmyr deposit and a CP survey on the most central diamonnd drill holes for Norsulfid A/S. The results are presented in company reports to the mining ministry commission, BV report 3977. Geochemistry: The showings were sampled and analysed for major and trace elements (AAS and wet chemical methods) during reconnaissance studies of object 48, 49 and 50 under early Grong Project (Logn, 1973). H. Karlstrøm (1990 and 1991) analysed the Skiftesmyr and Storedalen showings for 34 elements, including precious and ore metals using ICP and fire assay methods. Soil survey was carried out in 1996 (Geologiske Tjenester A/S) over Skiftesmyr and Stordalen and Stordalen East areas. Mineral Dressing: In 1977, on contract to Grong Gruber A/S, O. Eidsmo carried out an ore mineral flotation test and T. Malvik fine-grinding oremineral liberation tests of ore samples from drill hole material central to the orebody at Skiftesmyr. Diamond Drilling: Exploration diamond drilling started in 1973 by Grong Gruber A/S at Skiftesmyr and western Stordalen continued until 1979, in two periods 1973-75 and 1978-79. Norsulfid continued drilling in period 1990-93 to extend minable tonnage of deposit. 1) Grong Gruber A/S, in period 1973-79 drilled 22 holes ( = 4794m) on the Skiftesmyr orebody, including 4 holes (= 569m) on West Stordalen disseminated zone. 2) Norsulfid A/S, 1990-93, Skiftesmyr and West Stordalen zone, 38 holes (= 6807m), including 6 holes (= 1355m) drilled on Stordalen disseminated mineralization zone. Main showing (Hovedskjerp) Consists of a 12 m long, N-S trending trench which runs roughly perpendicular to geological trend in rocks. The rocks are strongly foliated to SSW and dips steeply to the NW (ca. 230°/80°). The trench was re-excavated, mapped and sampled in 1996. A 5m wide massive to semi-massive and disseminated ore zone crosses the trench is in sharp contact to a dark, magnetite-bearing quartzite (recrystallized chert) to the south and a pale coloured quartz-albite-sericite rich rock, interpreted as a hydrothermally altered felsic volcanite, to the north. The ore zone is divided into two parts, a 3 m section on the south, consisting mainly of a dark chlorite and quartz rich rock that is strongly disseminated with chalcopyrite (cp) and pyrrhotite (po). Much of this Cu rich mineralisation consists of patches and veins of remobilized cp and po. The north side of the ore zone consists of ca. 2m of medium- to coarse-grained massive pyrite with minor bands and patches of sphalerite (sl). Quartz and albite rich fragments and folded country rocks are common, found floating within the massive pyritic ore layer. The ore zone in this location is not representative of the orebody as a whole compared to what is registered in the drill holes.

Bibliography:

From NGU's Reference Archive:

Henriksen, G. , 1914

	Befaring av ertsforekomster mellom Sanddøla og Møklevann i Grong.

;Norges geologiske undersøkelse;FAGRAPPORT;Bergarkivet; No.BA 3034;3 pages

	Abstract:
	Flere skjerp mellom Sandøla og Møklevann. Generellt innholder mineraliseringene for lite kobber eller for mye magnetkis i svovelkisrike knopper. Følgende gruver og skjerp er besøkt. Damhaugen, Skiftesmyren, mutning no. 183, Rossetplass ved Myklevann, Godejordskjerpet og Finbuforekomsten. Videre arbeider anbefales ved enkelte av disse.

Bryn, E. (Myklevann) , 1917

	Rapport over: Myklevannsfeltet befart 5 og 6 juli 1917.

;Norges geologiske undersøkelse;FAGRAPPORT;Bergarkivet; No.BA 2211;3 pages

	Abstract:
	Rapporten er en befaringsrapport og kommenterer kort de forskjellige forekomster. Det konkluderes med at feltet kan ha sine muligheter men at disse er små.

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).

Logn, Ø. , 1973

	Geologiske, geofysiske og geokjemiske undersøkelser Grongfeltet/Grongprojektet.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.974

	Abstract:
	Objekt 48: Sandtjern skjerp Objekt 49: Skiftesmyra skjerp Objekt 50: Stordalen-anomaliene

Sakshaug, G.F. , 1974

	Elektromagnetisk undersøkelse Grongundersøkelsens objekter 48-51 Skiftesmyr - Møkkelvassås Skjerp

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1190A;15 pages

Sakshaug, G.F. , 1975

	Elektromagnetisk undersøkelse Grongundersøkelsens objekt 48-51 1. Møkkelvann - Brusvann 2. Skiftesmyr Vest 3. Finnbu

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1263;15 pages

Eidsvig, Per , 1975

	Ip- og CP-målinger Godejord og Skiftesmyr.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1287;13 pages

Abstract:

Det er tidligere utført undersøkelser i de to områder og de publikasjoner/rapporter i NGU's arkiv som er aktuelle er listet opp i nærværende rapport. De nye målingene foregikk på vanlig måte og på basis av stikningsnett brukt ved tidligere undersøkelser. Målingene viser at den kjente mineralisering ved Godejord har en utstrekning langs fallet på minst 130 - 150 meter. Ved Skiftesmyr har hovedmalmen en strøklengde på ca. 500 meter og en sannsynlig utstrekning mot dypet på 400 - 500 meter. Ved Skiftesmyr opptrer en rekke andre ledere av betydelige dimmensjoner.

Kihle, Ola , 1976

	CP-målinger Skiftesmyr, Rosset "grube" og Borvasselvas skjerp.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1346;18 pages

Sakshaug, G.F. , 1977

	Revurdering av Turammålinger 1973 Grongundersøkelsens objekter 48-51 Skiftesmyr - Møkkelvassås Skjerp

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1190B/til;6 pages

Kihle, Ola , 1978

	CP-målinger, Skiftesmyr, Nord.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1599;8 pages

Karlstrøm, Harald , 1994

	Edelmetaller i kisforekomster i Nord-Trøndelag

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.93.111;58 pages

Abstract:

De fleste kjente kismalmer (lagbundne massive sulfider) i Nord-Trøndelag er befart og analysert på edelmetaller og en serie andre elementer for å peke ut eventuelle provinser/subprovinser hvor edelmetaller eller andre økonomiske bestanddeler kan ha stor betydning. De undersøkte provinsene er Stjørdal-Selbu- området, Meråkerfeltet, Levanger-Verdal-Snåsa-området og Grongfeltet. Gull-anrikede kismalmer er påvist i den sydlige delen av Grongfeltet (Godejord- Skiftesmyr-Rosset) og i visse deler av Fundsjøgruppen i det vestlige Meråker- feltet. Deler av det østlige Meråkerfeltet (Lillefjell-Storhusmannsberget) inneholder forekomster med høye basemetall-innhold.

Heim, Michael , 1993

	Berggrunnsgeologiske undersøkelser i det sørvestlige Grongfeltet (Rosset - Godejord - Skiftesmyr - Finnbu)

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.92.311;36 pages

Abstract:

Berggrunnsgeologisk kartlegging er utført i et ca. 60 kvkm stort område sørvest i Grongfeltet, nord for Sanddøldalen. Det meste av området er del av Gjersvikdekket som dannes av flere dekkeflak med varierende intern petrografi og struktur. Dominerende er grønnstenskomplekset med overliggende vulkanoklastiske/sedimentære bergarter samt i hovedsak trondhjemittiske til gabbroide, subvulkanske intrusjoner. De fleste dekkeflak har invertert stratigrafi. Tektoniseringen under dekketransporten var penetra- tiv i de laveste, sørligste delene. I de nordligste delene kuttes eldre struk- turer av flakgrensene. Senkaledonske skjærsoner og forkastninger påvirker og reaktiverer tidligere strukturer i deler av området. En sen- til postkaledonsk forkastning (Sanddøla- Sandnes-Elstad "detachment") skjærer den kaledonske tektonostratigrafien og danner Gjersvikdekkets grense i sør og vest. Rossetforekomsten ligger i amfibolgneiser tilhørende en lavere tektonostrati- grafisk enhet (Skjøtingsdekket?) vestenfor Gjersvikdekket. Skiftesmyrområdet er del av Gjersvikdekkets hovedmasse og er rikt på sulfid- disseminasjoner. De fleste ligger omtrent konkordant i laminerte, basiske, dels andesittiske til dacittiske vulkanitter. Mulige stratabundne sulfider blir påvirket av en tidlig foldefase, mens mulige yngre mineraliseringssoner har dels gjennomsettende karakter. Godejord- og Finnbumineraliseringen har karakter av små, stratabundne forekom- ster i en sterkt og penetrativt deformert og metamorfosert vulkansk/vulkano- sedimentær lagpakke med stedvis rytmisk utvikling i lagrekken. Deler av prosjektområdet bør undersøkes nærmere i et oppfølgingsprogram.

References not to be found in NGU's Reference Archive.:

Elvebakk, H. 1991: TURAM og CP målinger Stordalen, Skiftesmyr. PTS-NTH rapport

Lindeman, E. 1992: Malmberegning av Skiftesmyr og Godejord. Bergvesenet rapport BV2882.

Lindeman, E. 1992: Underjordisk drift i Skiftesmyr. Bergvesenet Rapport BV2883

Lindeman, E. 1992: Skiftesmyr dagbrudd vurdering. Bergvesenet Rapport BV2885.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS96006	Dump	Sampler: Sandstad, J.S./...Stored: Løkken Comment: Brecciated ore, pyrrhotite-chalcopyrite veins/aggregates No. of registrated element analyses = 1
	JS96007	Dump	Sampler: Sandstad, J.S./...Stored: Løkken Comment: Pyrite-sphalerite ore, massive, fine to medium grained No. of registrated element analyses = 1
	JS96008	Bedrock	Sampler: Sandstad, J.S./...Stored: Løkken Comment: Chalcopyrite-pyrite veinlets in fine grained, felsic metavolcanite No. of registrated element analyses = 1
	1055	Bedrock	No. of registrated element analyses = 1
	1056	Bedrock	No. of registrated element analyses = 1
	1057	Bedrock	No. of registrated element analyses = 1
	1058	Bedrock	No. of registrated element analyses = 1
	1059	Bedrock	No. of registrated element analyses = 1
	1060	Bedrock	No. of registrated element analyses = 1
	1061	Bedrock	No. of registrated element analyses = 1

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

Name of Locality: Vestre skjerp

(Object Id: 450 10,01,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

(Coordinates NOT confirmed)

East:

384661 m.

North:

7152639 m.

Longitude:

12.6002860

Latitude:

64.4796020

Show on map

Resource

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

Resources and production

	Activity:	Pitting	Reserves:
	Operating method:		Historical production:

Information(s) in free text format

Free text

Not found in 1996.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	1069	Bedrock	No. of registrated element analyses = 1
	1070	Bedrock	No. of registrated element analyses = 1
	1071	Bedrock	No. of registrated element analyses = 1
	1072	Bedrock	No. of registrated element analyses = 1
	1073	Bedrock	No. of registrated element analyses = 1

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

Name of Locality: Midtre skjerp

(Object Id: 451 10,02,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

East:

384826 m.

North:

7152639 m.

Longitude:

12.6037150

Latitude:

64.4796580

Show on map

Resource

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

Resources and production

	Activity:	Pitting	Reserves:
	Operating method:		Historical production:

Information(s) in free text format

Free text

A 3-4 m long, N-S trending trench, lies along a major TURAM-EM anomaly. This trench is strongly covered by vegetation. The ore zone here appears to be represented by ca. 2 m (?) of massive pyritic ore and strongly pyrite disseminated dark chlorite rock. A magnetite-bearing recrystallized chert is found immediately to the north of the ore zone.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	1074	Bedrock	No. of registrated element analyses = 1
	1075	Bedrock	No. of registrated element analyses = 1
	1076	Bedrock	No. of registrated element analyses = 1
	1077	Bedrock	No. of registrated element analyses = 1
	1078	Bedrock	No. of registrated element analyses = 1

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

Name of Locality: Sørvestre skjerp

(Object Id: 6928 10,03,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

East:

384777 m.

North:

7172534 m.

Longitude:

12.5869430

Latitude:

64.6580070

Show on map

Resource

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

Resources and production

	Activity:	Pitting	Reserves:
	Operating method:		Historical production:

Information(s) in free text format

Free text

This showing lies along a major EM anomaly that can be traced directly NE to the main showing at Skiftesmyr. It consists of a 10 m long N-S trending trench. A 3 m thick massive pyrite zone occurs at the south end of the trench, in sharp contact to the south with a pale coloured, medium-grained gabbroic rock. The pyritic ore appears to be devoid of copper and zinc and is somewhat layered having thin layers and zones of dark chlorite rich bands and fragments that trend 310°/75°. The northern contact is more diffuse in nature, grading over to a dark chloritic rock with strong veining and disseminations of pyrite near the contact to the massive pyrite.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS96016	Bedrock	Sampler: Sandstad, J.S./...Stored: Løkken Comment: Pyrite ore, massive, fine grained, accessory chalcopyrite No. of registrated element analyses = 1

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

Name of Locality: Stordalen vest

(Object Id: 6929 10,04,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

East:

385156 m.

North:

7152559 m.

Longitude:

12.6106370

Latitude:

64.4790520

Show on map

Resource

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

Resources and production

	Activity:	Pitting	Reserves:
	Operating method:		Historical production:

Information(s) in free text format

Free text

This showing lies c. 200 m to the ESE of the Main Skiftesmyr showing at the south-western edge of Stordalen. The showing consists of a 5 m long N-S trending trench that is partly overgrown by moss and low shrubs. The trench cuts through dark, chlorite and amphibole rich layered and schistose rocks that trend to the south-west and dip steeply to the NW (260/75N). Several 10-50 cm wide zones of pale, quartz-albite-sericite rich rock, with minor amphibole and strongly disseminated and veined with quartz and pyrite + chalcopyrite-sphalerite. At the south end of the trench, numerous 1 to maximum 5 cm thick veins rich in coarse grained pyrite and quartz are found in a dark coloured chlorite rich strongly foliated rock. The mineralisation in this trench is associated with an isolated, shallow EM anomaly and appears to be separated from the larger, thick disseminated zone that stretches to the north along the western side of Stordalen. Immediately south of the trench, the rocks are finely layered felsic and mafic tuffs (?) that are in places tightly folded.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS96009	Dump	Sampler: Sandstad, J.S./...Stored: Løkken Comment: Pyrite-sphalerite-chalcopyrite veins/veinlets in quartz-chlorite-sericite rich, schist No. of registrated element analyses = 1
	JS96010	Dump	Sampler: Sandstad, J.S/...Stored: Løkken Comment: Pyritt+sphalerite+chalcopyrite ore, semi-massive, quartz-rich matrix No. of registrated element analyses = 1
	1079	Bedrock	No. of registrated element analyses = 1
	1080	Bedrock	No. of registrated element analyses = 1
	1081	Bedrock	No. of registrated element analyses = 1
	1082	Bedrock	No. of registrated element analyses = 1
	1083	Bedrock	No. of registrated element analyses = 1
	1084	Bedrock	No. of registrated element analyses = 1
	1085	Bedrock	No. of registrated element analyses = 1

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

Name of Locality: Stordalen nord

(Object Id: 6930 10,05,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

East:

385261 m.

North:

7153209 m.

Longitude:

12.6123100

Latitude:

64.4849150

Show on map

Resource

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

Resources and production

	Activity:	Pitting	Reserves:
	Operating method:		Historical production:

Information(s) in free text format

Free text

This showing consists of a 6 m long, E-W trending trench that cuts roughly perpendicular through strongly foliated, roughly N-S trending, steeply east-dipping (160°/85°) rocks dominated by pale, quartz-albite-sericite schists that carry variable disseminations and cm thick veins of quartz and pyrite + sphalerite. Some dm thick, dark zones rich in chlorite and strongly disseminated in coarse-grained pyrite + chalcopyrite are found at even ca. 1 m intervals in the paler rock. The mineralised zone in this trench lies along a strong, N-S trending EM anomaly that is associated with a thick, continuous disseminated zone that runs N-S along the western edge of Stordalen. This strongly disseminated zone, associated with quartz-albite, quartz-sericite and quartz-chlorite rich hydrothermally altered rock types, has been followed north through drill holes, trending directly into the main massive sulphide orebody at Skiftesmyr and has been interpreted as being part of the main feeder zone to the massive sulphides at Skiftesmyr.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	1110	Bedrock	No. of registrated element analyses = 1
	1111	Bedrock	No. of registrated element analyses = 1
	1112	Bedrock	No. of registrated element analyses = 1

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

Name of Locality: Stordalen øst

(Object Id: 6931 10,06,00)

Location

County:

Trøndelag

Municipality:

Grong (5045)

Map 1:50000:

Grong (1823-4)

Map 1:250000:

Grong

Coordinate system:

EU89-UTM Zone 33

(Coordinates NOT confirmed)

East:

385506 m.

North:

7152689 m.

Longitude:

12.6178100

Latitude:

64.4803350

Show on map

Resource

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

Information(s) in free text format

Free text

Not found in 1996.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	1104	Bedrock	No. of registrated element analyses = 1
	1105	Bedrock	No. of registrated element analyses = 1
	1106	Bedrock	No. of registrated element analyses = 1
	1107	Bedrock	No. of registrated element analyses = 1
	1108	Bedrock	No. of registrated element analyses = 1
	1109	Bedrock	No. of registrated element analyses = 1

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

---

Analyse Results

from

Deposit Area 5045 - 010 Skiftesmyr

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#
JS96006	Dump	8514	1775	1158	21	161	15.9	1054.0
JS96007	Dump	3620	57550	269	22	67	6.0	414.0
JS96008	Bedrock	8490	1034	349	13	43	7.3	809.0
JS96009	Dump	4628	5203	864	15	24	14.3	173.0
JS96010	Dump	4957	21644	421	19	31	13.3	198.0
JS96016	Bedrock	2264	102	10	19	15	6.1	265.0
1055	Bedrock	1091	3694	196	14	24	104.5	223.0
1056	Bedrock	2479	3264	281	9	73	5.9	202.0
1057	Bedrock	6664	913	741	26	65	10.6	532.0
1058	Bedrock	8051	1690	578	5	69	8.2	163.0
1059	Bedrock	4355	18897	191	8	58	5.4	149.0
1060	Bedrock	30062	2453	1272	18	37	43.7	9874.0
1061	Bedrock	6365	890	2917	13	45	43.7	3914.0
1069	Bedrock	186	720	16	17	54	.6	22.0
1070	Bedrock	153	76	4	26	37	.2	10.0
1071	Bedrock	230	1637	8	22	71	.6	29.0
1072	Bedrock	468	773	7	15	159	1.1	10.0
1073	Bedrock	1029	478	7	15	113	.5	7.0
1074	Bedrock	1298	537	9	25	112	1.2	15.0
1075	Bedrock	690	29	2	23	43	.3	5.0
1076	Bedrock	5566	831	13	25	106	3.2	16.0
1077	Bedrock	544	1557	5	24	99	.4	6.0
1078	Bedrock	1302	1114	23	28	114	1.7	18.0
1079	Bedrock	3620	718	479	49	49	11.3	1232.0
1080	Bedrock	526	120	19	18	43	2.2	383.0
1081	Bedrock	1289	2781	7	15	31	11.2	323.0
1082	Bedrock	2903	767	226	5	9	10.6	268.0
1083	Bedrock	8527	1036	28	35	43	17.1	1426.0
1084	Bedrock	5656	36527	27	14	27	12.9	425.0
1085	Bedrock	8624	25032	53	11	21	15.3	435.0
1104	Bedrock	24961	12738	5	22	10	33.9	206.0
1105	Bedrock	15186	5905	2	16	8	22.4	148.0
1106	Bedrock	2541	801	2	33	10	3.4	105.0
1107	Bedrock	2122	10280	2	23	10	5.2	94.0
1108	Bedrock	389	412	7	8	5	14.6	1223.0
1109	Bedrock	4064	20907	19	23	5	4.5	30.0
1110	Bedrock	11	168	6	86	2	.1	8.0
1111	Bedrock	4	229	2	8	13	2.5	124.0
1112	Bedrock	79	19	5	7	1	1.0	51.0

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

Sample No.	Pt#	Pd#	Rh#	As*	Cd*	Ba*	Mo*	Sb*	Bi*
JS96006	5.0	5.0	1.0	759	3.5	13	25.00	20	14
JS96007	4.0	4.0	1.0	150	155.2	10	4.00	2	-2
JS96008	-1.0	1.0	-1.0	321	3.0	7	4.00	10	12
JS96009	-1.0	-1.0	-1.0	62	17.0	19	8.00	2	8
JS96010	-1.0	1.0	-1.0	58	82.0	13	2.00	-2	6
JS96016	-1.0	-1.0	-1.0	26	-.2	5	1.00	-2	2
1055	4.0	3.0		201	11.9	11	14.00	2	5
1056	2.0	3.0		71	8.6	9	18.00	3	6
1057	7.0	4.0		408	3.2	10	26.00	6	14
1058	5.0	2.0		252	6.1	6	16.00	11	15
1059	3.0	4.0		133	59.9	3	3.00	2	5
1060	6.0	13.0		836	9.9	8	24.00	14	52
1061	3.0	14.0		958	3.3	6	32.00	32	64
1069	4.0	11.0		1218	2.4	6	7.00	2	4
1070	4.0	4.0		1131	.5	12	7.00	2	2
1071	4.0	15.0		2729	6.5	7	15.00	2	3
1072	6.0	10.0		136	3.6	7	12.00	2	2
1073	5.0	2.0		2	2.3	15	9.00	2	4
1074	1.0	2.0		8	2.0	12	43.00	2	13
1075	8.0	3.0		2	.7	10	116.00	2	5
1076	4.0	7.0		97	3.3	7	22.00	2	2
1077	1.0	2.0		2	4.4	16	34.00	2	15
1078	2.0	8.0		85	2.9	8	16.00	2	7
1079	3.0	4.0		82	2.7	27	3.00	2	13
1080	5.0	3.0		61	.2	14	2.00	2	2
1081	3.0	3.0		65	8.6	6	5.00	2	13
1082	1.0	2.0		35	2.1	10	2.00	5	2
1083	7.0	6.0		132	3.8	13	8.00	2	8
1084	1.0	3.0		86	133.2	11	7.00	2	2
1085	1.0	2.0		78	95.1	13	12.00	2	3
1104	3.0	3.0		10	20.7	5	2.00	2	2
1105	1.0	3.0		10	9.2	5	5.00	2	7
1106	1.0	2.0		17	2.1	12	1.00	2	8
1107	1.0	2.0		19	16.2	10	2.00	2	9
1108	2.0	2.0		21	1.4	19	12.00	2	2
1109	1.0	3.0		11	32.2	5	9.00	2	17
1110	1.0	3.0		17	.2	10	6.00	2	8
1111	1.0	2.0		2	.2	2	1.00	2	2
1112	1.0	2.0		10	.2	23	2.00	2	3

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

Sample No.	S%	V*	Cr*	Mn*	Fe%	Th*	U*	W*	Sr*
JS96006	21.26	22	3	122	37.21	-2.00	6.00	-2	9.0
JS96007	34.06	14	8	385	26.48	-2.00	-5.00	-2	8.0
JS96008	7.44	50	10	255	12.28	-2.00	-5.00	-2	43.0
JS96009	9.00	17	9	193	9.97	-2.00	-5.00	-2	13.0
JS96010	32.91	35	15	109	20.71	-2.00	-5.00	-2	8.0
JS96016	28.93	44	16	129	20.34	-2.00	-5.00	4	9.0
1055	13.22	14	8	75	12.74	10.00	5.00	4	27.0
1056	24.11	16	7	63	27.30	5.00	5.00	4	9.0
1057	22.30	16	5	50	28.17	6.00	5.00	1	5.0
1058	17.30	28	11	135	21.47	5.00	5.00	4	8.0
1059	33.32	3	4	121	23.96	3.00	5.00	2	1.0
1060	24.25	9	7	72	25.07	3.00	5.00	4	7.0
1061	25.26	15	5	88	23.74	5.00	5.00	1	9.0
1069	29.44	12	3	33	24.96	5.00	5.00	2	4.0
1070	11.64	18	7	57	11.43	5.00	5.00	1	4.0
1071	28.02	10	5	46	22.50	7.00	11.00	5	2.0
1072	21.13	15	9	74	29.95	4.00	5.00	1	3.0
1073	15.11	19	34	114	21.62	3.00	5.00	1	6.0
1074	20.09	8	1	96	32.54	6.00	5.00	1	3.0
1075	10.84	21	12	161	13.41	3.00	5.00	1	4.0
1076	22.27	9	2	143	31.88	5.00	5.00	1	6.0
1077	19.22	12	2	110	30.41	6.00	5.00	2	2.0
1078	20.52	9	2	143	33.34	5.00	5.00	1	5.0
1079	13.63	42	33	231	13.21	3.00	5.00	1	8.0
1080	32.21	23	5	50	17.39	4.00	5.00	1	12.0
1081	32.72	14	2	72	18.11	6.00	5.00	1	10.0
1082	4.28	5	1	33	4.44	2.00	5.00	1	3.0
1083	16.02	35	69	191	15.96	1.00	5.00	1	3.0
1084	31.97	8	1	41	18.38	2.00	5.00	1	2.0
1085	27.22	8	1	29	17.05	1.00	5.00	4	2.0
1104	14.83	83	1	364	12.26	2.00	5.00	1	3.0
1105	10.72	96	1	552	9.64	1.00	5.00	1	2.0
1106	18.73	126	3	480	15.95	2.00	5.00	1	2.0
1107	21.12	97	1	448	16.46	2.00	6.00	1	2.0
1108	6.21	237	7	561	12.21	3.00	5.00	1	6.0
1109	15.98	74	1	469	15.49	2.00	5.00	4	4.0
1110	22.39	133	1	612	22.20	2.00	5.00	1	1.0
1111	.39	59	8	753	4.65	1.00	5.00	1	12.0
1112	2.06	6	1	46	5.63	1.00	5.00	1	13.0

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

Sample No.	La*	B*
JS96006	5.00	-3
JS96007	3.00	5
JS96008	8.00	-3
JS96009	1.00	4
JS96010	2.00	3
JS96016	-1.00	-3
1055	16.00	2
1056	4.00	2
1057	7.00	2
1058	9.00	2
1059	2.00	2
1060	3.00	2
1061	3.00	2
1069	6.00	2
1070	4.00	2
1071	8.00	2
1072	5.00	2
1073	10.00	3
1074	3.00	7
1075	11.00	2
1076	3.00	2
1077	5.00	4
1078	2.00	9
1079	3.00	2
1080	2.00	4
1081	5.00	9
1082	2.00	7
1083	2.00	2
1084	2.00	5
1085	2.00	2
1104	2.00	2
1105	2.00	4
1106	2.00	3
1107	2.00	6
1108	2.00	3
1109	2.00	2
1110	2.00	3
1111	2.00	4
1112	11.00	2

---

The fact sheet was created on 02.05.2024

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

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