Contribution

The silicate lavas of Oldoinyo Lengai, Tanzania

Donaldson, C. H.; Dawson, J. B.; Kanaris-Sotiriou, R.; Batchelor, R. A.; Walsh, J. N.

Image de la premiere page de:

Neues Jahrbuch für Mineralogie - Abhandlungen Band 156 Heft 3 (1987), p. 247 - 279

45 références bibliographiques

publié: May 7, 1987

DOI: 10.1127/njma/156/1987/247

fichier Bib TeX

ArtNo. ESP154015603002, Prix: 29.00 €

Télécharger l'aperçu en format PDF Acheter la version digitale

Abstract

Olivine-free nephelinite-phonolite tuffs and lavas comprise > 99% of this carbonatite volcano. The lavas are peralkaline, rich in phenocrysts (principally nepheline) and were multiply saturated on eruption. Mineral chemistry and major- and trace-element whole-rock chemistry display regular changes in a suite of the lavas. However, the bulk compositions cannot be related to one another by computations modelling fractionation of the observed phenocrysts. Additional processes, including palagonitization and interaction of magmas with wall rocks have dispersed the rock compositions.

Mots-clefs

Nephelinite-phonolite tuffs • peralkaline lavas • major- and trace-element chemistry • mineral chemistry • nephelinite volcano • Oldoinyo Lengai • Tanzania