Effusive natrocarbonatite activity of Oldoinyo Lengai, June 1988

  title={Effusive natrocarbonatite activity of Oldoinyo Lengai, June 1988},
  author={J{\"o}rg Keller and Maurice Krafft},
  journal={Bulletin of Volcanology},
Oldoinyo Lengai in the Tanzanian rift valley is the only active carbonatite volcano in the world and its natrocarbonatitic lavas are unique in composition. The characteristics of effusive natrocarbonatite activity in June 1988 were studied and fresh samples were directly collected from active carbonatitic lava lakes and flows. Analyses of these samples provide the first information on natrocarbonatites since these unusual volcanic rock type was first described from the 1960–1961 eruptions. The… 

Fundamental changes in the activity of the natrocarbonatite volcano Oldoinyo Lengai, Tanzania

With a paroxysmal ash eruption on 4 September 2007 and the highly explosive activity continuing in 2008, Oldoinyo Lengai (OL) has dramatically changed its behavior, crater morphology, and magma

Differentiation of natrocarbonatite magma at Oldoinyo Lengai volcano, Tanzania

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

Tinderet volcano, Kenya: an altered natrocarbonatite locality?

Abstract The Tinderet volcano (19.9 to 5.5 Ma), located within the Kavirondo rift in Kenya, contains blocks of carbonatite lavas with calcite, minor apatite, fluorite, spinel-group minerals,

Evolution of Natrocarbonatite from a Wollastonite Nephelinite Parent: Evidence from the June, 1993 Eruption of Oldoinyo Lengai, Tanzania

Lapilli and unusually thick, high viscosity lavas extruded from Oldoinyo Lengai in June, 1993 are composed of crystal-rich natrocarbonatite containing a small proportion of porphyritic silicate

Experimental constraints on the crystallization of natrocarbonatitic lava flows

Natrocarbonatitic magmas are characterized by their extremely low viscosities and fast elemental diffusion, and as a consequence of this, their chemistry and crystallinity can change significantly

Nyerereite from calcite carbonatite at the Kerimasi Volcano, Northern Tanzania

The extinct Quaternary Kerimasi volcano located in the southern part of the Gregory Rift, northern Tanzania, contains both intrusive and extrusive calciocarbonatites. One carbonate mineral with a

The origin of melanophlogite, a clathrate mineral, in natrocarbonatite lava at Oldoinyo Lengai, Tanzania

Abstract We report new observations of a clathrate mineral, melanophlogite [46SiO2⋅6(N2,CO2)⋅2(CH4,N2)], as part of a tuffaceous layer within a sample of the 2006 natrocarbonatite lava, whose



Altered former alkalic carbonatite lava from Oldoinyo Lengai, Tanzania: Inferences for calcite carbonatite lavas

The active volcano Oldoinyo Lengai, Tanzania, is well known for its extrusions of alkalic carbonatite lava, first witnessed in 1960. An older carbonatite flow from the volcano was originally also

Temperature Measurements in Carbonatite Lava Lakes and Flows from Oldoinyo Lengai, Tanzania

The petrogenesis of carbonatites has important implications for mantle processes and for the magmatic evolution of mantle melts rich in carbon dioxide, and unusually low magmatic temperatures were confirmed with 1-atmosphere melting experiments on natural samples.

Peralkaline nephelinites

Two fractionation trends in sodic alkaline ultramafic liquids have been predicted from experiments in subsystems of the join Di-Ak-Ne-Lc-Qz. The products of these trends are equated with contrasting

Peralkaline nephelinites. I. Comparative petrology of Shombole and Oldoinyo L'engai, East Africa

Shombole, a nephelinite-carbonatite volcano in south Kenya, erupted silicate lavas, carbonatite dikes and tuffs, and pyroclastic rocks similar to those at other East African alkaline centres.

Carbonatite tuffs and lava clasts of the Tinderet foothills, western Kenya: a study of calcified natrocarbonatites

Miocene 'limestones' around Tinderet, noted for their mammalian fossils, but recognized as in part carbonatitic, are now shown to be carbonatite tuffs and volcaniclastics. They contain ejectamenta of

An experimental determination of primary carbonatite magma composition

Carbonatites are uncommon carbonate-rich rocks usually found in continental intra-plate regions and often associated with rifting. There has been much debate as to whether carbonatite magmas are

The role of liquid immiscibility in the genesis of carbonatites — An experimental study

AbstractThe two-liquid field between alkali-carbonate liquids and phonolite or nephelinite magmas from the Oldoinyo Lengai volcano has been determined between 0.7 and 7.6 kb and 900°–1,250° C. The

Physicochemical properties of alkali carbonatite lavas:Data from the 1988 eruption of Oldoinyo Lengai, Tanzania

Alkali carbonatite lavas extruded from Oldoinyo Lengai, Tanzania, in November 1988 are similar in composition to lavas extruded in 1960. Extrusion temperatures are 585 ±10 °C. Apparent viscosities in