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Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya.

Research output: Contribution to Journal/MagazineJournal article

Published

Standard

Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. / Macdonald, R.; Kjarsgaard, B. A.; Skilling, I. P. et al.
In: Contributions to Mineralogy and Petrology, Vol. 114, No. 2, 1993, p. 276-287.

Research output: Contribution to Journal/MagazineJournal article

Harvard

Macdonald, R, Kjarsgaard, BA, Skilling, IP, Davies, GR, Hamilton, DI & Black, S 1993, 'Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya.', Contributions to Mineralogy and Petrology, vol. 114, no. 2, pp. 276-287. https://doi.org/10.1007/BF00307762

APA

Macdonald, R., Kjarsgaard, B. A., Skilling, I. P., Davies, G. R., Hamilton, D. I., & Black, S. (1993). Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. Contributions to Mineralogy and Petrology, 114(2), 276-287. https://doi.org/10.1007/BF00307762

Vancouver

Macdonald R, Kjarsgaard BA, Skilling IP, Davies GR, Hamilton DI, Black S. Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. Contributions to Mineralogy and Petrology. 1993;114(2):276-287. doi: 10.1007/BF00307762

Author

Macdonald, R. ; Kjarsgaard, B. A. ; Skilling, I. P. et al. / Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. In: Contributions to Mineralogy and Petrology. 1993 ; Vol. 114, No. 2. pp. 276-287.

Bibtex

@article{372cd290707048f3a1dafd84bedefeb3,
title = "Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya.",
abstract = "Three thin, syn-caldera ash flow tuffs of the Suswa volcano, Kenya, contain pumiceous clasts and globules of trachytic glass, and clasts rich in carbonate globules, in a carbonate ash matrix. Petrographic and textural evidence indicates that the carbonate was magmatic. The trachyte is metaluminous to mildly peralkaline and varies from nepheline- to quartz-normative. The carbonate is calcium-rich, with high REE and F contents. The silicate and carbonate fractions have similar 143Nd/144Nd values, suggesting a common parental magma. Chondrite-normalized REE patterns are consistent with a carbonate liquid being exsolved from a silicate liquid after alkali feldspar fractionation. Sr isotopic and REE data show that the carbonate matrix of even the freshest tuffs interacted to some degree with hydrothermal and/or meteoric water. A liquid immiscibility relationship between the trachyte and carbonate is indicated by the presence of sharp, curved menisci between them, the presence of carbonate globules in silicate glass and of fiamme rich in carbonate globules separated by silicate glass, and by the fact that similar phenocryst phases occur in both melts. It is inferred that the carbonate liquid separated from a carbonated trachyte magma prior to, or during, caldera collapse. Viscosity differences segregated the magma into a fraction comprising silicate magma with scattered carbonate globules, and a fraction comprising carbonate globules in a silicate magmatic host. Explosive disruption of the magma generated silicate-and carbonate-rich clasts in a carbonate matrix. The silicate liquid was disaggregated by explosive disruption and texturally appears to have been budding-off into the carbonate matrix. After emplacement, the basal parts of the flows welded slightly and flattened. The Suswa rocks represent a rare and clear example of a liquid immiscibility relationship between trachyte and carbonate melts.",
author = "R. Macdonald and Kjarsgaard, {B. A.} and Skilling, {I. P.} and Davies, {G. R.} and Hamilton, {D. I.} and S. Black",
year = "1993",
doi = "10.1007/BF00307762",
language = "English",
volume = "114",
pages = "276--287",
journal = "Contributions to Mineralogy and Petrology",
issn = "0010-7999",
publisher = "Springer Verlag",
number = "2",

}

RIS

TY - JOUR

T1 - Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya.

AU - Macdonald, R.

AU - Kjarsgaard, B. A.

AU - Skilling, I. P.

AU - Davies, G. R.

AU - Hamilton, D. I.

AU - Black, S.

PY - 1993

Y1 - 1993

N2 - Three thin, syn-caldera ash flow tuffs of the Suswa volcano, Kenya, contain pumiceous clasts and globules of trachytic glass, and clasts rich in carbonate globules, in a carbonate ash matrix. Petrographic and textural evidence indicates that the carbonate was magmatic. The trachyte is metaluminous to mildly peralkaline and varies from nepheline- to quartz-normative. The carbonate is calcium-rich, with high REE and F contents. The silicate and carbonate fractions have similar 143Nd/144Nd values, suggesting a common parental magma. Chondrite-normalized REE patterns are consistent with a carbonate liquid being exsolved from a silicate liquid after alkali feldspar fractionation. Sr isotopic and REE data show that the carbonate matrix of even the freshest tuffs interacted to some degree with hydrothermal and/or meteoric water. A liquid immiscibility relationship between the trachyte and carbonate is indicated by the presence of sharp, curved menisci between them, the presence of carbonate globules in silicate glass and of fiamme rich in carbonate globules separated by silicate glass, and by the fact that similar phenocryst phases occur in both melts. It is inferred that the carbonate liquid separated from a carbonated trachyte magma prior to, or during, caldera collapse. Viscosity differences segregated the magma into a fraction comprising silicate magma with scattered carbonate globules, and a fraction comprising carbonate globules in a silicate magmatic host. Explosive disruption of the magma generated silicate-and carbonate-rich clasts in a carbonate matrix. The silicate liquid was disaggregated by explosive disruption and texturally appears to have been budding-off into the carbonate matrix. After emplacement, the basal parts of the flows welded slightly and flattened. The Suswa rocks represent a rare and clear example of a liquid immiscibility relationship between trachyte and carbonate melts.

AB - Three thin, syn-caldera ash flow tuffs of the Suswa volcano, Kenya, contain pumiceous clasts and globules of trachytic glass, and clasts rich in carbonate globules, in a carbonate ash matrix. Petrographic and textural evidence indicates that the carbonate was magmatic. The trachyte is metaluminous to mildly peralkaline and varies from nepheline- to quartz-normative. The carbonate is calcium-rich, with high REE and F contents. The silicate and carbonate fractions have similar 143Nd/144Nd values, suggesting a common parental magma. Chondrite-normalized REE patterns are consistent with a carbonate liquid being exsolved from a silicate liquid after alkali feldspar fractionation. Sr isotopic and REE data show that the carbonate matrix of even the freshest tuffs interacted to some degree with hydrothermal and/or meteoric water. A liquid immiscibility relationship between the trachyte and carbonate is indicated by the presence of sharp, curved menisci between them, the presence of carbonate globules in silicate glass and of fiamme rich in carbonate globules separated by silicate glass, and by the fact that similar phenocryst phases occur in both melts. It is inferred that the carbonate liquid separated from a carbonated trachyte magma prior to, or during, caldera collapse. Viscosity differences segregated the magma into a fraction comprising silicate magma with scattered carbonate globules, and a fraction comprising carbonate globules in a silicate magmatic host. Explosive disruption of the magma generated silicate-and carbonate-rich clasts in a carbonate matrix. The silicate liquid was disaggregated by explosive disruption and texturally appears to have been budding-off into the carbonate matrix. After emplacement, the basal parts of the flows welded slightly and flattened. The Suswa rocks represent a rare and clear example of a liquid immiscibility relationship between trachyte and carbonate melts.

U2 - 10.1007/BF00307762

DO - 10.1007/BF00307762

M3 - Journal article

VL - 114

SP - 276

EP - 287

JO - Contributions to Mineralogy and Petrology

JF - Contributions to Mineralogy and Petrology

SN - 0010-7999

IS - 2

ER -