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	THE ORE DATABASE
	Deposit Area 1664 - 013
	(Last updated 04.jul.2023)

Importance

Public:

(No data)

Economical:

Minor interest , (Confirmed 03.jul.2023 by Jan Sverre Sandstad)

Mineralization

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

Main grain size:

Fine grained (< 1 mm)

Main alteration:

	Strike/Dip:	15 / 65	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

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

Group:

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Quartz	Major mineral (>10%)
	Ore mineral	Magnetite	Major mineral (>10%)
	Ore mineral	Hematite	Major mineral (>10%)
	Ore mineral	Pyrite	Accessory mineral (<1%)

Lithology:

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

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Host rock	Foliation	Strike/Dip :15 / 65	Post-mineralisation ;...Effect :Modifies

Information(s) in free text format

Free text

Forekomsten ligger på en skogkledd kolle rett øst for Amdalsveien. Den består av en ca. 20 m lang, 3-4 m bred dagskjæring med en 8 m lang vannfylt synk. Vertsbergarten er en finkornet, magnetittførende, båndet kvartsitt som gjennomskjæres av kvartsårer med dels svak disseminasjon av pyritt. Sonen med jernmalm er 2-3 m mektig og består av både båndet hematitt-kvarts med noe magnetitt og kvartssliret magnetitt med noe hematitt. Analyser av prøver fra den store tippen i skråningen nedenfor gir opptil 33 % Fe2O3. På toppen av åsen finnes massiv, lys grønn grønnstein mens fyllittiske bergarter finnes i veiskjæringene.

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
	Blomdalen 1	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Banded hematite-quartz, some magnetite No. of registrated element analyses = 1 No. of registrated oxide analyses = 1
	Blomdalen 2	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Quartz-lenses in magnetite ore, some hematite No. of registrated element analyses = 1 No. of registrated oxide analyses = 1
	Blomdalen 3	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Quartz-magnetite with quartz-pyrite veinlets No. of registrated element analyses = 1

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

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Analyse Results

from

Deposit Area 1664 - 013 Blomdalen

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#
Blomdalen 1	Dump	4	5	0	4	20	-.1	-.5
Blomdalen 2	Dump	3	27	0	5	21	-.1	4.5
Blomdalen 3	Dump	14	12	1	4	12	.1	14.0

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Sample No.	Pt#	Pd#	As*	Cd*	Ba*	Mo*	Sn*	Sb*	Bi*
Blomdalen 1			1	-.1	1	1.00	-1	1	-0
Blomdalen 2			1	-.1	-1	1.50	-1	-0	-0
Blomdalen 3	-5.0	2.0	10	-.0	10	1.05	-0	0	0

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

Sample No.	Se*	Ga*	Ge*	In*	S%	V*	Cr*	Mn*	Fe%
Blomdalen 1	-0.50	1.40			-.02	30			32.69
Blomdalen 2	-0.50	2.40			-.02	45			23.31
Blomdalen 3	1.00	1.27	0.06	-0.01	1.83	20	11	319	10.55

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Sample No.	Th*	U*	W*	Rb*	Sr*	Y*	Zr*	Nb*	Ta*
Blomdalen 1	-0.20	0.40	1	-0.1	19.6	1.7	4	0.30	-0.10
Blomdalen 2	-0.20	-0.10	-1	-0.1	7.0	1.3	3	0.20	-0.10
Blomdalen 3	0.04	0.10	0	0.5	2.4	0.4	2	0.30	-0.05

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

Sample No.	Cs*	La*	Ce*	Pr*	Nd*	Sm*	Eu*	Gd*	Tb*
Blomdalen 1	-0.10	1.40	1.30	0.17	0.80	0.15	0.04	0.19	0.03
Blomdalen 2	-0.10	0.70	0.80	0.13	0.60	0.11	0.04	0.19	0.03
Blomdalen 3	-0.05	-0.50	0.36

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Sample No.	Dy*	Ho*	Er*	Tm*	Yb*	Lu*	Li*	Be*	Na*
Blomdalen 1	0.23	0.05	0.18	0.02	0.17	0.02		-1
Blomdalen 2	0.23	0.05	0.11	0.02	0.13	0.02		1
Blomdalen 3							1	-0	100

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Sample No.	Mg*	Al*	P*	K *	Ca*	Sc*	Ti*	Te*	Hf*
Blomdalen 1			393						-0.10
Blomdalen 2			262						-0.10
Blomdalen 3	200	700	60	300	200	0.20	80	0.08	-0.10

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

Sample No.	Re*	Hg*	Tl*
Blomdalen 1		-0	-0
Blomdalen 2		-0	-0
Blomdalen 3	-0		-0

Oxide analyses

( All values are in % )

Sample No.	Sample Type	SiO2	Al2O3	TiO2	Fe2O3	MnO	MgO	CaO
Blomdalen 1	Dump	51.90	0.21	0.02	46.74	0.03	0.03	0.33
Blomdalen 2	Dump	67.54	0.19	0.01	33.32	0.06	0.03	0.08

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

Sample No.	Na2O	K2O	P2O5	Sum
Blomdalen 1	0.11	-0.01	0.09	99.00
Blomdalen 2	0.07	-0.01	0.06	101.00

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The fact sheet was created on 19.05.2024

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

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