Norsk versjon
	THE INDUSTRIAL MINERAL DATABASE
	Occurence 4214 - 351 Glosheia
	(Object Id: 8279) (Last updated: 04.05.2015)

Mineralization

	Era:	Proterozoic	Period:	Mesoproterozoic
	Dating:	1060 (-10\+10) million year	Method:	U/Pb
	Genesis:	Pegmatite formation	Form:	Lens
	Main texture:	Granoblastic	Min. distribution:	Massive (>50 % ore minerals)

Main grain size:

Very unevenly grained

	Strike/Dip:		Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Proterozoic

Period:

Mesoproterozoic

	Province:	South Norwegian Basement Province
	Geotec.unit:	Agder Complex
	Tectonic complex:
	Igneous complex:

Group:

Formation:

Mineralogy

	Mineral	Amount
	Quartz	Major mineral (50-90%)
	Potassic feldspar	Major mineral (50-90%)

Information(s) in free text format

Free text

The desposit is situated 0.5 km sotuh of Lake Selestølvann. Its a well investigated pegmatite. Its is a well well developed and regular zoned pegmatite with a quartz core. The pegmatite is devided in to 5 zones + quarts core. Zone 1: quarts with biotite amd microcline. Zone 2 : monomineralic plagioclase. Zone 3: thin zone with occurence of rare minerals alike allanite euxinite and apatite. Zone 4: Graphic feldspar Zone 5: graphic welspar with myrmecite. R. Åmli gives a detailed description of this pegatite and its zoning. The pegmatite is today known to be the locatlity for the worlds largest occurence of allanite crystals and is suitable, for collectetion of allanite for rare earth separation research.

Bibliography:

From NGU's Reference Archive:

Åmli, Reidar , 1977

	Internal structure and mineralogy of the Gloserheia granite pegmatite, Froland, Southern Norway.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.57 (3);243-262 pages

Abstract:

The GLoserheia granite pegmatite shows a well developed and regular zoning around the quartz core. Eight different zones have been recognized. The following minerals occur, quartz, microcline, plagioclase, biotite, muscovite, muscovite 1 M, chlorite, apatite, calcite, tourmaline, rutile, yttrotitanite, magnetite, hematite, pyrite, beryl, zircon, allanite, uraninite, thorite, xenotime, monazite, euxenite, fourmarierite, kasolite, ß-uranophane and uranophane.

Andersen, Olaf , 1931

	Feltspat II. Forekomster i fylkene Buskerud og Telemark, i flere herreder i Aust-Agder og i Hidra i Vest-Agder.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.128B;1-109 pages

Abstract:

Summary s. 151. Feldspar deposits in Southern Norway. (Feltspat II by Olaf Andersen and Feltspat III by Tom F.W. Barth) A few years ago one of the writers published a general outline of the properties, mode of occurrence, exploitation and uses of feldspar with special reference to the Norwegian feldspar industry (Olaf Anderesn, Feltspat I, Norges geologiske undersøkelse, Nr. 128A, 1926). To that publication the reader is referred for general in- formation regarding the feldspar industry of Norway. In the present publi- cation brief descriptions are given of 262 individual feldspar deoposits, all situated in the part of Southern Norway that extends, generally in a rather narrow zone, along the coast westward from the neighbourhood of Kragerø to the island Hidra near Flekkefjord. The deposita described lie in the counties Buskerud, Telemark, Aust-Agder and Vest-Agder, and are distributed over a large number of local districts (herreder). The most important districts at present are those in the neighbourhood of Kragerø ((Bamble, Skåtøy and Sannidal), those along the coast between Risør and Arendal (especially Søndeled, Holt and Froland), and the two districts north of Kristiansand (Iveland and Evje). Each description contains information about the dimensions and general attitude of the pagmatite body and the feldspar.

Andersen, Olaf , 1926

	Feltspat I. Feltspatmineralenes egenskaper, forekomst og praktiske utnyttelse med særlig henblikk på den norske feltspatindustri.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.128A;1-142 pages

Abstract:

The present publication is a description, in non-technical language, of the properties, geological mode of occurrences, exploitation, and uses of feldspar with special reference to the Norwegian feldspar industry. Systematic descriptions of commercial deposits are reserved for a future publication to be issued as no. 128b of the present series. Chapter 1 contains a general description of the mineralogical, chemical, and physical properties of the various species of the feldspar group. - Table I gives the theoretical chemical composition of mixture of potash feldspar and soda feldspar for intervals of 10 pct. by weight. - Table 2 gives the corresponding figures for mixtures of soda feldspar and lime feldspar. - Table 3 contains a few examples of chemical analyses of feldspar from Norwegian occurrences. The analyses, of which No.s 1-5 are new, represent selected, "pure" feldspar. No.s 1, 2 and 3 are commercial "potash feldspars" from granite pegmatites, No. 4 a soda-potash feldspar from syenite pegmatite, and No. 5 a soda feldspar of commercial quality from a pyroxene bearing granite pegmatite. No.s 6 and 7 are old analyses respectively of oligoclase from granite pegmatite and labradorite from anorthosite. - Table 4 contains multiplication factors for the recalculation of feldspar analyses.

Baadsgaard, Halfdan; Chaplin, Catherine; Griffin, William L. , 1984

	Geochronology of the Gloserheia pegmatite, Froland, southern Norway.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.64 (1);111-119 pages

Abstract:

Relatively unaltered feldspars from the Gloserheia pegmatite yield an Rb-Sr isochron age of 1062 ± 11 Ma (M.S.W.D. = 90, Sr1 = 0.7023 ± 0.0002) and Pb-Pb isochron age of 1085 ± 28 Ma. The best age of pegmatite crystallization is given by a U-Pb concordia-discordia intersection at 1060 (+8, -6) Ma. from euxenite samples. The radiometric age limit the last major metamorphism in the area to > 1060 Ma, although mild later hydration has reset Rb-Sr mineral dates on muscovite and biotite to as low as ~850 Ma. O, Sr and Pb isotope data indicate that the pegmatite magma was derived from a mantle source.

Åmli, Reidar , 1975

	Mineralogy and rare earth geochemistry of apatite and xenotime from the Gloserheia granite pegmatite, Froland, southern Norway.

;TIDSSKRIFTARTIKKEL;American mineralogist; No.60;607-620 pages

Abstract:

The Gloserheia granite pegmatite, situated in the Precambrian Kongsberg-Bamble formation, contains eight different zones (core, intermediate zones I-V, wall zone, and border zone). Apatite occurs in the core and in zones I and III. Xenotime has been found included in apatite from all three zones, and in other parageneses within these zones. The apatite close to xenotime inclusions is depleted in REE. Zoning of xenotime is characterized by an enrichment of the light REE relative to the heavy REE, from the center towards the rim of the crystal. Xenotime crystals included in apatite from the outer zones show less relative enrichment in the light REE than do those in the inner zones of the pegmatite. No such trend in REE fractionation is shown by xenotimes from other parageneses. The rare earth minerals included in apatite are considered to have formed by exsolution, possibly accompanied by metasomatism. Fractionation in the apatite-xenotime system was caused by processes bearing a simple relation to the crystallization of the zones where these minerals occur. In contrast, the REE fractionation in the other xenotimes probably has a more complex relation to the sequence of zones in the pegmatite.

Åmli, Reidar , 1973

	The Gloserheia granite pegmatite. Selected studies in geology, mineralogy and rare earth geochemistry.

;UiO Geografisk inst.;AVHANDLING

---

The fact sheet was created on 30.04.2024

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

Copyright © 2024 Geological Survey of Norway