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	THE ???? DATABASE
	Occurence 0 - 000 FEIL
	(Object Id: ) (Last updated: 07.03.2017)

Operations

	From - To	Activity	Comments
	2007 - 2011	Geochemistry	Company/Institution :Scandinavian Resources
			Nearly 10000 samples (soil, stream samples).
	2008 - 2008	Geophysics	Company/Institution :Scandinavian Resources
			TEM (only profiles) and Magnetometry
	2009 - 2009	Geophysics	Company/Institution :Scandinavian Resources
			Ground magnetic survey
	2009 - 2011	Geology	Company/Institution :Scandinavian Resources
	2010 - 2010	Core drilling	Company/Institution :Scandinavian Resources
			6 holes totaling 680 m at two localiities.
	2011 - 2011	Geophysics	Company/Institution :NGU
			Magnetometry, EM, Radiometry
	2011 - 2013	Geology	Company/Institution :NGU

Mineralization

	Era:	Proterozoic	Period:
	Genesis:	Metamorphic formation	Form:	Layer
	Main texture:	Structureless	Min. distribution:	Irregular (scattered)

Main grain size:

Fine grained (< 1 mm)

Main alteration:

Sericitisation

	Strike/Dip:	120 / 90	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Proterozoic

Period:

Mesoproterozoic

	Province:	Troms-Finnmark Basement Province
	Geotec.unit:
	Tectonic complex:	Mauken Tectonic Window
	Igneous complex:

Group:

Målselva Group

Formation:

Aurevatn Formation

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Quartz	Major mineral (>10%)
	Gangue mineral	Muscovite	Major mineral (>10%)
	Gangue mineral	Biotite	Major mineral (>10%)
	Gangue mineral	Feldspar	Major mineral (>10%)
	Gangue mineral	Sericite	Major mineral (>10%)
	Gangue mineral	Epidote	Subordinate mineral (1-10%)
	Gangue mineral	Tourmaline	Accessory mineral (<1%)
	Ore mineral	Pyrrhotite	Major mineral (>10%)
	Ore mineral	Arsenopyrite	Major mineral (>10%)
	Ore mineral	Gold	Accessory mineral (<1%)
	Ore mineral	Chalcopyrite	Accessory mineral (<1%)

Lithology:

	Relationship	Rock	Origin
	Host rock	Siltstone	Sedimentary
			Metamorphic facies :Greenschist
	Host rock	Sandstone	Sedimentary
			Metamorphic facies :Greenschist

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Host rock	Foliation	Strike/Dip :120 / 90	Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Scandinavian Highlands (SH) started their prospecting campaign in the Mauken area in 2007 and soon discovered gold anomalies in their stream sediment samples. Further work, including reconnaissance airborne TEM and magnetic surveys, soil sampling, mapping and rock sampling led to the discovery of the so-called "Main Zone", located in sediments close to the contact to the massive greenstone. The company did trenching and chip sampling at several localities along the zone, resulting in that gold values up to 6 g/t were found in a zone 4-6 m wide and over a length of 1800 m (SH press release, 2011). The zone was drilled at two localities in 2010 (total of 6 holes), but the results of the drilling were not promising. No more exploration work has been done by the company on this target since 2010. The mineralization is situated c. 100 m structurally and stratigraphically above the contact to the massive greenstone, in a steep to vertically dipping sequence of interbedded siltstone and sandstone. This sedimentary sequence is 150-200 m thick, and grades upwards into a > 600 m thick layer of rhythmically alternating, silty to more coarse sandstone, possibly a turbiditic sequence. The contact to the structurally underlying greenstone is marked by a 50-100 m layer of calc-brecciated greenstone, which includes thin lenses of calcite marble. The main mineralization is hosted by the more fine-grained siltstone and sandstone, and the maximum thickness is 2.5 m to 2.7 m. Sedimentary structures like cross-bedding and graded bedding are locally present, indicating that the mineralized sequence has right-way-up towards the northeast. The metasediments consist of irregular clastic grains of feldspar and quartz in a very fine-grained matrix of biotite and muscovite. Tourmaline is a common accessory, the boron indicating a seawater environment. The matrix minerals are commonly overgrown by late-stage clinozoisite/epidote and muscovite. Arsenopyrite and pyrrhotite are the main sulfide minerals and occur mainly disseminated, but locally concentrated in thin bands. Chalcopyrite is a common accessory phase, associated with pyrrhotite. Arsenopyrite occurs as hypidioblastic to idioblastic elongated grains, up to several mm in length. It contains inclusions of the other sulfides, and appears to be a later phase than these. The arsenopyrite grains are quite frequently associated with elongate quartz aggregates or lenses, while the hosting sediments commonly show varying degree of sericitization in bands close to the sulfides. Gold occur as small (10-20 microns) inclusions in arsenopyrite. A few small inclusions of gold are found in pyrrhotite and are also present in the silicate matrix. Four samples from the mineralization were analyzed by NGU for a number of elements and show that the mineralization contains only gold (up to 4 ppm Au) and arsenic (up to 0.98 % As), while contents of base metals such as Cu, Zn and Pb are less than a few hundreds of ppm. The "Main Zone" is localized in sand-/siltstone close to the contact to underlying greenstone, and this contact zone may have been important with respect to the formation of the mineralization. The restricted thickness (up to 2.7 m) and extent of the mineralized zone (some 600 m), as well as low grade (only sporadic > 1 ppm gold), is clearly not economic. However, the zone disappears into a swampy area to the southeast and is covered by vegetation to the northwest. One possible source of gold and arsenic in this setting is carbonaceous sediments, which are known to concentrate a number of metals in early formed, diagenetic iron sulfides (Large et al., 2011, Thomas et al., 2011). At Mauken, close to the contact to the underlying greenstone, the siltstone is quite rich in graphite, and also contains minor amounts of iron sulfides. According to a model for orogenic gold deposits presented by Large et al. (2011), gold, arsenic and sulfur are preferentially released from the diagenetic sulfides because of recrystallization during later metamorphism. The resulting fluids may follow structural pathways and deposit the metals higher up in the sequence. In the case of Mauken, the fluids may have been concentrated along or close to the greenstone-sediment contact.

References

Large, R.R., Bull, S.W., Maslennikov, V., 2011: A carbonaceous sedimentary source-rock model for Carlin-type and orogenic gold deposits. Economic Geology, v.106, p.331-358. Thomas, H.V., Large. R.R., Bull, S.W., Maslennikov, V., Berry, R.F., Fraser, R., Froud, S., and Moye, R., 2011: Pyrite and pyrrhotite and composition in sediments, laminated quartz veins, and reefs at Bendigo gold mine, Australia: Insights for ore genesis. Economic Geology, v.106, p.1-32.

Bibliography:

From NGU's Reference Archive:

Bjerkgård, Terje; Henderson, Iain; Sandstad, Jan Sverre; Schönenberger, Johannes; Slagstad, Trond , 2015

	Geology of the Mauken tectonic window, Målselv, Troms

;Norges geologiske undersøkelse;RAPPORT;NGU-rapport; No.2015.013;60+kart pages

Abstract:

This report presents the results from bedrock mapping in the Mauken tectonic window, carried out in several periods in 2011-2013. During the NGU MINN program, the Mauken area has been subject to a high-resolution airborne geophysical survey (magnetometry, radiometry, EM), followed by bedrock mapping and structural geology investigations. The work in the Mauken area is part of a larger project in southern Troms, with the goal to work out a structural-tectonic-metallogenic model and interpretaion for the basement areas in the whole region.

Berthelsen, Asger , 1967

	Geologic and structural studies around two geophysical anomalies in Troms, Northern Norway.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.247;57-77 pages

Abstract:

The geology and structures of two windows (the Mauken and the Divielva windows, see fig. 1) are outlined. For the Precambrian supracrustal rocks of the Mauken window, two formations names and one group name are suggested. Hyolithus zone sediments in autochthonous position along the southern margin of the Mauken window show that the Caledonian thrusting exeeded 70 km. In both window structures "ReliefÏberschiebung" took place. A magnetic anomaly in the Mauken window is explained by local concentrations of normally accessoric magnetite in an antiformal hinge zone in sericite-chlorite schists. The relations between an E-W directed magnetic anomaly and the structures of the Divielva window are discussed.

Fareth, E. , 1983

	Målselv. Berggrunnskart; Målselv; 14332; 1:50 000; sort/hvitt;

;Norges geologiske undersøkelse;KART

Fareth, E. , 1982

	Takvatnet. Berggrunnskart; Takvatnet; 15333; 1:50 000; sort/hvitt;

;Norges geologiske undersøkelse;KART

Zwaan, K.B.; Fareth, E.; Grogan, P.W. , 1998

	Tromsø. Berggrunnskart Tromsø M 1:250 000; trykt i farger

;Norges geologiske undersøkelse;KART;1 kart pages

	Abstract:
	Beskrivelsen finnes på kartet.

Bjerkgård, Terje; Slagstad, Trond; Henderson, Iain H.C.; Sandstad, Jan Sverre; Schönenberger, Johannes , 2015

	Geology and gold mineralisation in the Mauken Precambrian basement window, Målselv, Troms, northern Norway

;Geological Society of Norway;ARTIKKEL;Norwegian journal of geology; No.95 (3/4);423-443 pages

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

Alnes, A.M., 2013: Geological setting and origin of a gold-mineralized zone at Myrefjellet, Mauken, Troms. Master thesis, University of Tromsø, Norway 96 pp.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JSS_1	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken Comment: Qtz-apy veins in dark grey siltstone, 100 below main zone No. of registrated element analyses = 1
	TB-MA_1	Bedrock	Sampler: T. Bjerkgård/...Stored: Løkken Comment: Siltstone with apy and po No. of registrated element analyses = 1
	TB-MA_50	Bedrock	Sampler: T. Bjerkgård/...Stored: Løkken Comment: Arsenopyrite in siltstone No. of registrated element analyses = 1
	TB-MA_51	Bedrock	Sampler: T. Bjerkgård/...Stored: Løkken Comment: Arsenopyrite in siltstone No. of registrated element analyses = 1

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

Name of Locality: Trench 1

(Object Id: 32847 18,01,00)

Location

County:

Municipality:

Mangler ()

Map 1:50000:

Takvatnet (1533-3)

Map 1:250000:

Tromsø

County:

UTM-Zone 33 - EUREF89/WGS84

Resource

	Resource Type:	Precious metals (Au,Ag,PGE)	Resource Subtype:	Gold
			Element(s):	Au As

Resources and production

	Activity:	Exploration	Reserves:
	Operating method:		Historical production:

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The fact sheet was created on 29.04.2024

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