Fact Sheet for <b>Occurence 1813

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	THE INDUSTRIAL MINERAL DATABASE
	Occurence 1813 - 316 Bolvær
	(Object Id: 14979) (Last updated: 08.07.2010)

Location

County:

Nordland

Municipality:

Brønnøy (1813)

Map 1:50000:

Brønnøysund (1725-1)

Map 1:250000:

Mosjøen

Coordinate system:

EU89-UTM Zone 33

(Coordinates NOT confirmed)

East:

364500 m.

North:

7265999 m.

Longitude:

12.0722540

Latitude:

65.4880550

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Resource

Resource Type:

Olivine

Resource Subtype:

Ultramafic (unspec.)

Importance

Raw material meaning:

Not Assessed (reg. 18.02.2015)

Mineralization

Era: Paleozoic Period:

Genesis: Form:

Main texture: Min. distribution:

Main grain size:

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Stratigraphic classification of host rock

Era: Paleozoic Period:

Province:

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Igneous complex:

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Bibliography:

From NGU's Reference Archive:

Heldal, T.; Hjelmeland, H. , 1988

Brønnøysund. Berggrunnskart; Brønnøysund; 17251; 1:50 000; sort/hvitt;

;Norges geologiske undersøkelse;KART

Heldal, Tom , 2001

Ordovician stratigraphy in the western Helgeland Nappe Complex in the Brønnøysund area, North-central Norway.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU Bulletin; No.438;47-61 pages

Abstract:

In the western part of the Helgeland Nappe Complex, a small ophiolite fragment (the Bolvær Complex) and a metasedimentary succession (the Brønnøysund Group) are exposed on several islands to the west of Brønnøysund. The Bolvær Complex was emplaced, uplifted and subject to subaerial weathering and erosion prior to the deposition of the Brønnøysund Group. The uncomformity defines an irregular topographic surface which was gradually filled with sediments during a regional transgression, probably influenced by active tectonics. The sedimentation of the Brønnøysund Group initially started with the build-up of a coastal setting, delivering coarse and fince clastiscs into a shallow-marine environment (Risøy Formation). This formation is stratigraphically overlain by calcareous turbidites (Torgnes Formation), pelites (Aspøy Formation) and carbonate rocks (Toftsund Formation). The Brønnøysund Group is correlated with several cover sequences above ophiolites in the Helgeland Nappe Complex, and deposition in Early to Middle Orodovician time is suggested. The clast population in conglomerates and the composition of finer clastic sediments show an exotic, ensialic source for the detritus, in addition to the ophiolite. The ensialic source consisted essentially ofpsammites and schists, deformed and metamorphosed prior to the deposition of the Brønnøysund Group.

Era:	Paleozoic	Period:
Genesis:		Form:
Main texture:		Min. distribution:

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	Geotec.unit:
	Tectonic complex:
	Igneous complex: