The world's only active carbonatite volcano, with jacupirangite, nepheline syenite and other rocks. Extremely alkali-rich lava, 30 % Na2O.
References:
- Guest, N.J. (1956) The volcanic activity of Oldoinyo L'Engai, 1954. Rec. Geol. Surv. Tanganyika: 4: 56-59
- Dawson, J.B. (1962) Sodium carbonatite lavas from Oldoinyo Lengai, Tanganyika. Nature: 195: 1075-1076
- Milton, C. (1968) The "natro-carbonatite lava" of Oldoinyo Lengai, Tanzania. Geological Society of America Special Paper 121: 202 (abstract)
- Peterson, T.D. (1986) Sodium metasomatism and mineral stabilities in alkaline ultramafic rocks: implications for the origin of the sodic lavas of Oldoinyo Lengai. Eos: 67: 617 (abstract)
- Peterson, T.D. (1989) Peralkaline nephelinites II. Low pressure fractionation and the hypersodic lavas of Oldoinyo Lengai. Contributions to Mineralogy and Petrology: 102: 336-346
- Peterson, T.D. (1990) Petrology and genesis of natrocarbonatite. Contributions to Mineralogy and Petrology: 105: 143-155
- Mitchell, R.H. (1997) Carbonate-carbonate immiscibility, neighborite and potassium iron sulphide in Oldoinyo Lengai natrocarbonatite. Mineralogical Magazine: 61: 779-789
- Dawson, J.B. and Hll, P.G. (1998) Mineral chemistry of peralkaline combeite-lamprophyllite nephelinite from Oldoinyo Lengai, Tanzania. Mineralogical Magazine: 62: 179-196
- Pettibon, C.M., Kjarsgaard, B.A., Jenner, G.A., and Jackson, S.E. (1998) Phase relationships of a silicate-bearing natrocarbonatite from Oldoinyo Lengai at 20 and 1000 MPa. Journal of Petrology: 39: 2137-2151
- Mitchell, R.H. and Belton, F. (2004) Niocalite-cuspidine solid solution and manganoan monticellite from natrocarbonatite, Oldoinyo Lengai, Tanzania. Mineralogical Magazine: 68: 787-799
- Dawson, B. (2008): A volcanic voyage of discovery. Elements, 4, 138-139
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http://www.earlham.edu/~graveti/oldoinyolengai.htm
28 entries listed. 24 valid minerals. 3 type localities (valid minerals).
