1-20 OF 188 RESULTS FOR

natrocarbonatite

Results shown limited to content with bounding coordinates.
Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
×Close Modal
Sort by
Journal Article
Published: 01 August 2006
The Canadian Mineralogist (2006) 44 (4): 857-876.
...Jörg Keller; Anatoly N. Zaitsev Abstract Carbonatite dykes are described for the first time from the active natrocarbonatite volcano Oldoinyo Lengai, Tanzania. The dykes are fine grained, with a microporphyritic texture of polycrystalline, granular calcite microphenocrysts. The porous texture...
FIGURES | View All (13)
Journal Article
Published: 01 November 2013
American Mineralogist (2013) 98 (11-12): 1998-2006.
...Andrew D. Beard; Kieren Howard; Laura Carmody; Adrian P. Jones Abstract We report new observations of a clathrate mineral, melanophlogite [46SiO 2 ·6(N 2 ,CO 2 )·2(CH 4 ,N 2 )], as part of a tuffaceous layer within a sample of the 2006 natrocarbonatite lava, whose composition reflects the typical...
FIGURES | View All (10)
Journal Article
Published: 01 April 2013
Mineralogical Magazine (2013) 77 (3): 213-226.
... indicate that the Tinderet carbonatites are similar to natrocarbonatites from the Oldoinyo Lengai and Kerimasi volcanoes that have altered and recrystallized to form calcite carbonatites. These data support the hypothesis that some of the Tinderet carbonatites were originally alkali-rich rocks which...
FIGURES | View All (7)
Series: GSA Special Papers
Published: 01 June 2011
DOI: 10.1130/2011.2478(08)
... Fieldwork was conducted in the active north crater of Oldoinyo Lengai volcano, Tanzania. Gases, aqueous fumarole condensates, and freshly erupted natrocarbonatite lavas were collected from several hornitoes associated with the same eruptive center and are considered to represent genetically...
Journal Article
Published: 01 December 2008
Mineralogical Magazine (2008) 72 (6): 1261-1277.
...R. H. Mitchell; F. A. Belton Abstract A unique hybrid natrocarbonatite, collected from the new ash cone of the volcano Oldoinyo Lengai, Tanzania in July 2008, consists of phenocrysts of nyerereite and gregoryite together with xenocrysts of clinopyroxene, nepheline and Ti-andradite set...
FIGURES | View All (18)
Journal Article
Published: 01 August 2008
The Canadian Mineralogist (2008) 46 (4): 971-980.
... the solidus at ~550°C, discrete exsolved inclusions of (Na,K)Cl ss occur in (K,Na)Cl ss and of (K,Na)Cl ss in (Na,K)Cl ss . These data are relevant to the differentiation and crystallization of the natrocarbonatitic melt at Oldoinyo Lengai under hypabyssal and plutonic conditions; they predict the formation...
FIGURES | View All (11)
Journal Article
Published: 01 August 2006
Mineralogical Magazine (2006) 70 (4): 437-444.
...R. H. Mitchell Abstract Stalactites formed by the chemical weathering of natrocarbonatite lava decorate the roofs of hollow inactive hornitos at Oldoinyo Lengai, Tanzania. The stalactites are composed principally of trona with lesser and very variable amounts of nahcolite, (NaHCO 3 ), thermonatrite...
FIGURES | View All (8)
Journal Article
Published: 01 April 2006
Mineralogical Magazine (2006) 70 (2): 211-218.
...R. H. Mitchell Abstract Lapilli formed by a Strombolian eruption are associated with the formation of a large lava flow of natrocarbonatite on or about 21–22 July, 2000 at Oldoinyo Lengai volcano, Tanzania. Fresh lapilli consist of vesicular natrocarbonatite similar to that occurring in rapidly...
FIGURES | View All (6)
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...
FIGURES | View All (8)
Journal Article
Published: 01 October 2004
Mineralogical Magazine (2004) 68 (5): 787-799.
...R. H. Mitchell; F. Belton Abstract Lapilli and spatter of natrocarbonatite extruded from the T56B cone of Oldoinyo Lengai (Tanzania) in August 2003 are unusually rich in apatite, silicate, oxide and sulphide minerals. These minerals occur primarily within inclusions of quenched natrocarbonatite...
FIGURES | View All (14)
Journal Article
Published: 01 February 1999
Mineralogical Magazine (1999) 63 (1): 53-55.
...B. C. Jago; J. Gittins Several K-Fe sulphide minerals have been described from natrocarbonatite lavas erupted from the Tanzanian volcano Oldoinyo Lengai but uncertainty remains about their exact identity. They do not appear to be any of the established K-Fe sulphides according to Dawson et al...
Journal Article
Published: 01 December 1998
Mineralogical Magazine (1998) 62 (6): 759-768.
...J. Gittins; B. C. Jago Abstract Natrocarbonatite magma, erupted as lava flows in the Tanzanian volcano Oldoinyo Lengai in June and November of 1988, has evolved chemically since its formation. The June and November flows of 1988 display increasing Cl, F, Ba, K, Mg and Mn, concomitantly with Na, Ca...
Journal Article
Published: 01 December 1997
Mineralogical Magazine (1997) 61 (6): 779-789.
...Roger H. Mitchell Abstract Porphyritic natrocarbonatite lavas erupted from the Oldoinyo Lengai volcano (Tanzania) on 17 October 1995 and 15-19 December 1995 differ from previously studied lavas in that they preserve textures indicative of groundmass carbonate-carbonate immiscibility. The immiscible...
Journal Article
Published: 01 June 1997
Mineralogical Magazine (1997) 61 (3): 351-355.
... natrocarbonatite lava that has been erupted in more recent times. This proposition is difficult to reconcile with the currently fashionable hypothesis whereby the natrocarbonatite lava separated immiscibly from a type of nephelinite magma, most recently thought to be a wollastonite nephelinite. In 1993 Dawson...
Journal Article
Published: 01 April 1997
European Journal of Mineralogy (1997) 9 (2): 351-364.
Journal Article
Published: 01 February 1994
Journal of the Geological Society (1994) 151 (1): 59-63.
.... in press. Petrology and geochemistry of Oldoinyo Lengai lavas, extruded November, 1988: Magma source, ascent and crystallisation. In : Bell, K. & Keller, J. (eds) Carbonatite volcanism of Oldoinyo Lengai and petrogenesis of natrocarbonatite. IAVCEI Proceedings in Volcanology. Gittins J...
Journal Article
Published: 01 April 1990
Journal of the Geological Society (1990) 147 (2): 213-216.
...B. T. NGWENYA; D. K. BAILEY Abstract Fine grained carbonatite in the Kaluwe complex has been inferred, on textural grounds, to be calcified natrocarbonatite. Electron microprobe analysis, however, shows that the brown laths thought to be pseudo-nyerereite are dolomitic, with Sr values much higher...
Journal Article
Journal: Geology
Published: 01 October 1983
Geology (1983) 11 (10): 599-602.
... of premodern natrocarbonatite volcanism. The principal carbonate mineral was nyerereite, which is the dominant mineral in modern natrocarbonatite lava flows of the adjacent volcano Oldoinyo Lengai. The nyerereite of Kerimasi was leached of its alkalis by meteoric water and is now represented by calcite...
Journal Article
Journal: Geology
Published: 15 April 2019
Geology (2019) 47 (6): 527-530.
...Tibor Guzmics; Márta Berkesi; Robert J. Bodnar; András Fall; Enikő Bali; Ralf Milke; Enikő Vetlényi; Csaba Szabó Abstract Earth’s only active natrocarbonatite volcanism, occurring at Oldoinyo Lengai (OL), Tanzania, suggests that natrocarbonatite melts are formed through a unique geological process...
FIGURES | View All (4)
Journal Article
Published: 01 August 2008
The Canadian Mineralogist (2008) 46 (4): 843-860.
...Anatoly N. Zaitsev; Jörg Keller; John Spratt; Elena N. Perova; Anton Kearsley Abstract Samples of natrocarbonatite showing various degrees of alteration are preserved in an older carbonatite platform that existed before and until the 1917 explosive eruption at Oldoinyo Lengai volcano, in Tanzania...
FIGURES | View All (13)