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	(Object Id: ) (Last updated: 04.07.2023)

Mineralization

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

Main grain size:

Fine grained (< 1 mm)

Main alteration:

Chloritisation

	Strike/Dip:	10 / 30	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

	Province:	Caledonides
	Geotec.unit:	Trondheim Nappe Complex
	Tectonic complex:
	Igneous complex:

Group:

Støren

Formation:

Mineralogy

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

Lithology:

	Relationship	Rock	Origin
	Wall rock	Greenschist	Extrusive Original rock :Basalt
			Metamorphic facies :Greenschist

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Host rock	Foliation	Strike/Dip :10 / 30	Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Tre mindre skjerp i grønnstein finnes nær Mariakirken på Vollen i Mostadmarka. Det nordligste av disse består av et 0,5 m høyt innhugg i en 4 m høy skjæring i skifrig grønnstein med en 30-40 cm mektig sulfidsone nederst. Det er ikke mulig å prøveta denne, men prøver fra tippen fører slirer med pyritt med mindre mengder magnetkis og spor av kobberkis i kvarts. Sulfidsonen i de andre to skjerpene er også 20-40 cm mektige og består av disseminasjon av pyritt og mindre mengder kobberkis i omvandlet grønnstein.

Bibliography:

From NGU's Reference Archive:

Torske, Tore , 1965

	Geology of the Mostadmarka and Selbustrand area, Trøndelag.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.232;1-83 + ka pages

Abstract:

The bedrock of the area consists of metamorphic epiclastic, volcanic, and intrusive rocks of assumed Lower Ordovician age, assigned to, and lithologically matching the rocks of, the Røros, Støren and Lower Hovin Groups of the Trondheim Region. A detailed petrographic description of the rock varieties is given. The metamorphic grade of all rocks corresponds to the Greenschist Facies. - Small ore deposits occur in connection with the volcanic rocks. They comprise pyrite-pyrrhotite ores of the Leksdal Type, mixed pyrite-magnetite ores, and iron oxide ores. - Lithological variations of the sedimentary rocks is tentatively correlated with events during the early periods of the Caledonian Orogeny. - The volcanism within the area seems to have started with a phase of explosive activity, followed by extrusion (mostly submarine) of copious amounts of spilitic lavas; towards the end of the main period of volcanism a new episode of explosive activity has produced what is called the upper pyroclastic horizon, comprising rocks ranging from coarse volcanic breccia to finegrained tuffs. - The intrusive rocks consist mainly of saussurite gabbros and quartz keratophyres. The latter are thought to be intrusive rather than effusive, and evidence is offered to support this. In some places the character of pyroclastic material points to a quartz keratophyre parentage. Thus, quartz keratophyres may have occurred both as intrusive and volcanic rocks.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	Vollen 2-2	Dump	Sampler: T.Bjerkgård/...Stored: Løkken/...Size(kg): 2 Comment: Irregular lenses of pyrite-pyrrhotite, some chalcopyrite in quartz No. of registrated element analyses = 1

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

Name of Locality: Skjerp 1

(Object Id: 37457 14,01,00)

Location

County:

Municipality:

Mangler ()

Map 1:50000:

Stjørdal (1621-1)

Map 1:250000:

Trondheim

County:

UTM-Zone 33 - EUREF89/WGS84

Resource

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

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	Vollen 2-1	Bedrock	Sampler: J.S.Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Pyrite disseminastion in altered greenstone No. of registrated element analyses = 1

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

Name of Locality: Skjerp 2

(Object Id: 37458 14,02,00)

Location

County:

Municipality:

Mangler ()

Map 1:50000:

Stjørdal (1621-1)

Map 1:250000:

Trondheim

County:

UTM-Zone 33 - EUREF89/WGS84

Resource

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

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The fact sheet was created on 27.04.2024

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