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nyerereite

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Journal Article
Published: 01 November 2022
American Mineralogist (2022) 107 (11): 2054–2064.
... Carbonates in the system Na 2 CO 3 -CaCO 3 are nowadays suggested as having a wide stability field at conditions of the mantle transition zone. Our structural analysis of nyerereite, which has limited stability fields at ambient conditions, and its similarities with already known carbonates that are stable...
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Journal Article
Published: 01 October 2009
Mineralogical Magazine (2009) 73 (5): 797–816.
...F. Kaminsky; R. Wirth; S. Matsyuk; A. Schreiber; R. Thomas Abstract Nyerereite and nahcolite have been identified as micro- and nano-inclusions in diamond from the Juina area, Brazil. Alongside them are Sr- and Ba-bearing calcite minerals from the periclase-wüstite series, wollastonite II (high...
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Journal Article
Published: 01 August 2008
The Canadian Mineralogist (2008) 46 (4): 843–860.
..., in Tanzania. The carbonatite samples contain two mineral assemblages: the first consists of relict primary magmatic minerals: nyerereite, fluorite, apatite-(CaF), barite, magnetite and khanneshite. The second consist of low-temperature subsolidus minerals: pirssonite, calcite, shortite, nahcolite, trona...
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Journal Article
Published: 01 August 2008
The Canadian Mineralogist (2008) 46 (4): 1079–1095.
... in the groundmass of the host kimberlite. Rasvumite occurs in chloride–“nyerereite” and carbonate clasts, where it forms prismatic crystals (up to 5 mm) or is associated with djerfisherite in a rim around pyrrhotite. Djerfisherite is the omnipresent sulfide in all types of chloride-containing clasts, in which...
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Journal Article
Published: 01 February 2006
Mineralogical Magazine (2006) 70 (1): 103–114.
...R. H. Mitchell Abstract Natrocarbonatite lavas erupted from hornitos T37B and T49B at Oldoinyo Lengai (Tanzania) during 23–30 July, 2000 are unusual in containing sylvite and fluorite microcrysts together with fluorite-nyerereite intergrowths. The latter are relatively coarse grained and exhibit...
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Image
Crystal structure of ( a ) <span class="search-highlight">nyerereite</span> and ( b ) aragonite in the ( a-b ) pl...
Published: 01 November 2022
Figure 7. Crystal structure of ( a ) nyerereite and ( b ) aragonite in the ( a-b ) plane. Aragonite is shown in the 2 × 1 × 2 supercell to highlight the similarities with nyerereite. Colors are as follows: yellow is Na; blue is Ca; red is O; dark and light brown are C1 (in nyerereite
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BSE images of groundmass <span class="search-highlight">nyerereite</span> and barian <span class="search-highlight">nyerereite</span> in lava (T37B). N...
Published: 01 February 2006
F ig . 4. BSE images of groundmass nyerereite and barian nyerereite in lava (T37B). Note that the barian nyerereite forms epitaxial mantles on the nyerereite laths. x = khannesite/burbankite; g = groundmass gregoryite-like mineral; n = nyerereite; b = barian nyerereite. Fluorite (mid-grey
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Compositions of <span class="search-highlight">nyerereite</span>, barian <span class="search-highlight">nyerereite</span> and gregoryite plotted in the...
Published: 01 February 2006
F ig . 5. Compositions of nyerereite, barian nyerereite and gregoryite plotted in the system Na 2 CO 3 -K 2 CO 3 -CaCO 3 (mol.%). Note that compositions of barian nyerereite are not ternary and are plotted only for comparison with those of groundmass nyerereite. G = gregoryite; NY = nyerereite
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Backscattered electron images of experimental products. ( a ) Bastnäsite an...
Published: 01 December 2022
) Burbankite and lukechangite in sample BCN-18. ( e ) Oval calcite grains and hexagonal plates of bastnäsite in glass (BCN-15). ( f ) Burbankite, bastnäsite, and minor calcite (BCN-19). ( g ) Burbankite, nyerereite, and natrite in sample BCN-38; ( h ) burbankite and nyerereite in sample BCN-34. Abbreviations
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Compositions (wt.%) of alkali carbonates occurring as inclusions in calcite...
Published: 27 November 2020
Fig. 8. Compositions (wt.%) of alkali carbonates occurring as inclusions in calcite from Trig Point Hill calcite (C2), Kerimasi calcite carbonatite, and afrikandite (this work), compared with the compositions of Oldoinyo Lengai nyerereite (Zaitsev et al. , 2009 ) and Kerimasi nyerereite
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CaCO 3  ( top left ) and Na 2 CO 3  layers ( top right ) constitute nyerere...
Published: 01 November 2022
Figure 5. CaCO 3 ( top left ) and Na 2 CO 3 layers ( top right ) constitute nyerereite structure and their superimposition in nyerereite structure ( bottom ). Ca, Na, C(1)O 3 , and C(2)O 3 atoms are colored in blue, yellow, dark brown, and light brown, respectively. (Color online.)
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BSE image of a gregoryite phenocryst with trapped inclusions of natrocarbon...
Published: 01 February 2006
F ig . 6. BSE image of a gregoryite phenocryst with trapped inclusions of natrocarbonatite magma which have crystallized to nyerereite (n) with epitaxial barian nyerereite (white) mantles. Note the preferred orientation of the nyerereite laths.
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Na-Ca-K composition diagram for <span class="search-highlight">nyerereite</span> from different localities. Data ...
Published: 01 October 2009
F ig . 5. Na-Ca-K composition diagram for nyerereite from different localities. Data on nyerereite from natrocarbonatites after Gittins and McKie ( 1980 ), Peterson ( 1990 ), Zaitsev and Chakhmouradian ( 2002 ), Mitchell ( 2006 ), Zaitsev et al . ( 2008 a , b ). Data on nyerereite from
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BSE images of fluorite-<span class="search-highlight">nyerereite</span> intergrowths T49B. Note: the typical abse...
Published: 01 February 2006
F ig . 3. BSE images of fluorite-nyerereite intergrowths T49B. Note: the typical absence of fluorite and/or nyerereite in the sylvite microcrysts ( a,b,d ); the rare gregoryite-sylvite intergrowth ( a ); and the granular ‘cotectic texture’ and presence of apatite and manganoan magnetite in ( c
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Compositions (mol.%) of experimentally formed <span class="search-highlight">nyerereite</span> plotted in the sys...
Published: 01 August 2008
F ig . 11. Compositions (mol.%) of experimentally formed nyerereite plotted in the system Na 2 CO 3 – K 2 CO 3 – CaCO 3 . Data points for nyerereite crystallized from the bulk compositions with 10 wt.% (open squares) and 20 wt.% (solid circles) halide (50:50 NaCl:KCl wt.%) are shown
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( A, B ) Backscattered electron images of the 1993 Oldoinyo Lengai carbonat...
Published: 01 October 2021
Figure 2. ( A, B ) Backscattered electron images of the 1993 Oldoinyo Lengai carbonatite lava, showing phenocrysts of nyerereite (elongated, brighter) and gregoryite (round, darker) set in the nyerereite–gregoryite–sylvite–fluorite ground-mass. ( C ) The immiscible nephelinitic melt with a micro
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Representation of a portion of the <span class="search-highlight">nyerereite</span> unit-cell content where selec...
Published: 01 November 2022
Figure 6. Representation of a portion of the nyerereite unit-cell content where selected atomic sites are shown (Na1 and Na2 in yellow, Ca in blue, C1 in dark brown, and C2 in light brown). A schematic representation of the bond length for the O4, O5, and O6 atoms bonding C2 is illustrated being
Journal Article
Published: 01 December 2022
American Mineralogist (2022) 107 (12): 2242–2250.
... ) Burbankite and lukechangite in sample BCN-18. ( e ) Oval calcite grains and hexagonal plates of bastnäsite in glass (BCN-15). ( f ) Burbankite, bastnäsite, and minor calcite (BCN-19). ( g ) Burbankite, nyerereite, and natrite in sample BCN-38; ( h ) burbankite and nyerereite in sample BCN-34. Abbreviations...
FIGURES
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Raman spectra: a, <span class="search-highlight">Nyerereite</span> from the inclusion in nepheline ( Fig. 5  l );...
Published: 01 December 2015
Fig. 10. Raman spectra: a, Nyerereite from the inclusion in nepheline ( Fig. 5 l ); b , alumoåkermanite (Mel) from the inclusion in nepheline ( Fig. 5 d ); c , nyerereite from the inclusions in forsterite ( Fig. 7 g ); d , magnesite from the inclusions in forsterite ( Fig. 7 i ).
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a. Replacement of pirssonite (dark grey) by calcite (light grey); the grey ...
Published: 01 August 2008
F ig . 7. a. Replacement of pirssonite (dark grey) by calcite (light grey); the grey mineral in the core of the phenocryst is nyerereite. Sample OL 360. BSE. b. Full pseudomorph of pirssonite after nyerereite with abundant calcite. Black corresponds to empty space. Sample OL 360. BSE.