Abstract
Trace element data, including the REE, are reported for natrocarbonatites collected during the 1988 effusive period of Oldoinyo Lengai, Tanzania. These data, together with trace element data for the phenocryst phases nyerereite and gregoryite and for a related peralkaline nephe-linite, provide the basis for discussing petrogenetic hypotheses related to alkalic carbonatites. Natrocarbonatites are characterized, compared to the more common calciocarbonatites, dolomitic carbonatites, and ferrocarbonatites, by extreme fractionation of the REE, with (La/Sm)N ratios >40, high concentrations for Sr, Ba, Rb, K, unusually high contents of Mo, W, U, As and Sb and strong depletion in Ta, Nb, Hf, Zr, Ti, Y, Yb and Lu. The trace element signature of natrocarbonatite as compared with the more common alkali-poor carbonatites shows that Lengai lavas represent exotic compositions so far restricted to this volcano, and cannot be used to model petrogenetic schemes for carbonatites in general. Liquid immiscibility is a viable model for the derivation of natrocarbonatite from an exceptionally peralkaline nephelinite.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Bell K, Blenkinsop J (1989) Neodymium and strontium isotope geochemistry of carbonatites. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 278–300.
Cullers RL, Medaris G Jr (1977) Rare earth elements in carbonatite and cogenetic alkaline rocks. Examples from Seabrook Lake, Callander Bay, Ontario. Contrib Mineral Petrol 65:143–153.
Dawson JB (1962) Sodium carbonate lavas from Oldoinyo Lengai, Tanganyika. Nature 195:1075–1076.
Dawson JB, Gale NH (1970) Uranium and thorium in alkalic rocks from the active volcano Oldoinyo Lengai (Tanzania). Chem Geol 6:221–231.
Dawson JB, Garson MS, Roberts B (1987) Altered former alkalic carbonatite lava from Oldoinyo Lengai, Tanzania: inferences for calcite carbonatite lavas. Geology 15:765–768.
Dawson JB, Smith JV, Steele IM (1989) Combeite (Na2.33Ca1.74Others0.12) Si3O9 from Oldoinyo Lengai, Tanzania. J Geol 97:365–372.
Dawson JB, Pinkerton H, Norton GE, Pyle DM (1990) Physicochemical properties of alkali carbonatite lavas: data from the 1988 eruption of Oldoinyo Lengai. Geology 18:260–263.
Deans T (1966) Economic mineralogy of African carbonatites. In: Tuttle OF, Gittins J (eds) Carbonatites. Wiley, New York, pp 385–413.
Deans T, Roberts B (1984) Carbonatite tuffs and lava clasts of the Tinderet foothills, western Kenya: a study of calcified natrocarbonatites. J Geol Soc Lond 141:563–580.
Donaldson CH, Dawson JB, Kanaris-Sotiriou R, Batchelor RA, Walsh JN (1987) The silicate lavas of Oldoinyo Lengai, Tanzania. Neues Jahrb Miner Abh 156:247–279.
Eby GN (1975) Abundance and distribution of the rare earth elements and yttrium in the rocks and minerals of the Oka carbonatite complex, Quebec. Geochim Cosmochim Acta 39:597–620.
Freestone IC, Hamilton DL (1980) The role of liquid immiscibility in the genesis of carbonatites — an experimental study. Contrib Mineral Petrol 73:105–117.
Gerasimovsky VI (1978) Geochemistry of the carbonatites of the East African Rift Zones. In: Proc 1st Int Symp on Carbonatites, Pocos de Caldas, Minas Gerais, Brasil. Ministerio das Minas e Energia, Brasilia, pp 207–212.
Gittins J (1989) The origin and evolution of carbonatite magmas. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 580–600.
Gittins J, McKie D (1980) Alkalic carbonatite magmas: Oldoinyo Lengai and its wider applicability. Lithos 13:213–215.
Hamilton DL, Bedson P, Esson J (1989) The behaviour of trace elements in the evolution of carbonatites. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 405–427.
Hay RL (1983) Natrocarbonatite tephra of Kerimasi volcano, Tanzania. Geology 11:599–602.
Hogarth DD (1989) Pyrochlore, apatite and amphibole: distinctive minerals in carbonatite. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 105–148.
Hornig I (1988) Spurenelementuntersuchungen an Karbonatiten mit Hilfe der ICP-Atomemissionsspektroskopie. PhD Thesis, University Freiburg, 273pp.
Javoy M, Pineau F, Staudacher T, Cheminée JL, Krafft M (1989) Mantle volatiles sampled from a continental rift: the 1988 eruption of Oldoinyo Lengai. TERRA Abstr 1:324.
Keller J (1989) Extrusive carbonatites and their significance. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 70–88.
Keller J, Krafft M (1989) Composition of natrocarbonatite lavas, Oldoinyo Lengai 1988. TERRA Abstr 1:286.
Keller J, Krafft M (1990) Effusive natrocarbonatite activity of Oldoinyo Lengai, June 1988. Bull Volcanol 52:629–645.
Kjarsgaard BA, Hamilton DL (1989) The genesis of carbonatites by immiscibility. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 388–404.
Koster van Groos AF, Wyllie PJ (1968) Liquid immiscribility in the join NaAlSi3O8-Na2CO3— H2O and its bearing on the genesis of carbonatites. Am J Sci 266:932–967.
Le Bas MJ (1987) Nephelinites and carbonatites. In: Fitton JG, Upton BGJ (eds) Alkaline igneous rocks. Geol Soc Spec Publ Lond 30:53–83.
Mariano AN (1989) Nature of economic mineralization in carbonatites and related rocks. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 149–176.
Mariano AN, Roeder PL (1989) Kerimasi — a neglected carbonatite volcano. J Geol 91:449–455.
Nelson DR, Chivas AR, Chappell BW, McCulloch MT (1988) Geochemical and isotopic systematics in carbonatites and implications for the evolution of ocean-island sources. Geochim Cosmochim Acta 52:1–17.
Peterson TD (1989a) Peralkaline nephelinites I. Comparative petrology of Shombole and Oldoinyo Lengai, East Africa. Contrib Mineral Petrol 101:458–478.
Peterson TD (1989b) Peralkaline nephelinites II. Low pressure fractionation and the hypersodic lavas of Oldoinyo Lengai. Contrib Mineral Petrol 102:336–346.
Peterson TD (1990) Petrology and genesis of natrocarbonatite. Contrib Mineral Petrol 105:143–155.
Sun SS, Hanson GN (1976) Rare earth element evidence for differentiation of McMurdo volcanics, Ross Island, Antarctica. Contrib Mineral Petrol 54:139–155.
Sun SS, McDonough WF (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: Saunders AD, Norry MJ (eds) Magmatfsm in the oceanic basins. Geol Soc Spec Publ Lond 42:313-345.
Twyman JD, Gittins J (1987) Alkalic carbonatite magmas: parental or derivative? In: Fitton JG, Upton BGJ (eds) Alkaline igneous rocks. Geol Soc Spec Publ Lond 30:85-94.
Wallace ME, Green DH (1988) An experimental determination of primary carbonatite magma composition. Nature 335:343–346.
Williams RW, Gill JB, Bruland KW (1986) Ra-Th disequilibria systematics: Timescale of carbonatite magma formation at Oldoinyo Lengai volcano, Tanzania. Geochim Cosmochim Acta 50:1249–1259.
Woolley AR, Kempe DRC (1989) Carbonatites: nomenclature, average chemical compositions, and element distribution. In: Bell K (ed) Carbonatites — genesis and evolution. Unwin Hyman, London, pp 1–14.
Wyllie PJ, Baker MB, White BS (1990) Experimental boundaries for the origin and evolution of carbonatites. Lithos 26:3–19.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1995 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Keller, J., Spettel, B. (1995). The Trace Element Composition and Petrogenesis of Natrocarbonatites. In: Bell, K., Keller, J. (eds) Carbonatite Volcanism. IAVCEI Proceedings in Volcanology, vol 4. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-79182-6_6
Download citation
DOI: https://doi.org/10.1007/978-3-642-79182-6_6
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-79184-0
Online ISBN: 978-3-642-79182-6
eBook Packages: Springer Book Archive