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	Occurence 0 - 000 FEIL
	(Object Id: ) (Last updated: 04.07.2023)

Mineralization

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

Main grain size:

Fine grained (< 1 mm)

Main alteration:

	Strike/Dip:		Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

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

Group:

Støren Group

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Quartz	Major mineral (>10%)
	Ore mineral	Hematite	Major mineral (>10%)
	Ore mineral	Magnetite	Major mineral (>10%)

Lithology:

	Relationship	Rock	Origin
	Host rock	Jasper	Sedimentary Original rock :Exhalite
			Metamorphic facies :Greenschist

Information(s) in free text format

Free text

Gaddmyra ligger sør for Vika-gårdene i et flatt og skogbevokst område og er ikke lett å finne uten hjelp av GPS-koordinatene. Den består av en Ø-V orientert, 7 m lang og 0,7-1,5 m bred vannfylt dagskjæring. Jaspis med en 10 cm mektig, tilnærmet flattliggende kvartsåre er blottet i en knaus i sørveggen av skjæringa. Magnetitt ser ut til å være noe anriket i grålig jaspis nær kvartsåra og i tillegg finnes disseminasjon av magnetitt og hematitt i jaspis.

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.

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

Bakmark, N. & Rø, G 2014, Jerngruver, natur- og kulturminner i nærheten av Mostadmark jernverk - TURBOK. Mostadmark Jernverks Venner, 144 s.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	Gaddmyra-1	Bedrock	Sampler: J.S.Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Magnetite-hematite in fine-grained greyish jasper No. of registrated element analyses = 1 No. of registrated oxide analyses = 1
	Gaddmyra-2	Bedrock	Sampler: J.S.Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Hematite-magnetite in gryish red jasper No. of registrated element analyses = 1 No. of registrated oxide analyses = 1

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

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The fact sheet was created on 28.04.2024

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