Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils

S. Opfergelt; R. B. Georg; K. W. Burton; R. Guicharnaud; C. Siebert; S. R. Gislason; A. N. Halliday

doi:10.1016/j.apgeochem.2011.03.044

Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils

S. Opfergelt
, R. B. Georg
, K. W. Burton
, R. Guicharnaud
, C. Siebert
, S. R. Gislason
, A. N. Halliday

Science Institute

University of Iceland

Research output: Contribution to journal › Article › peer-review

Abstract

Weathering of basaltic ash in volcanic areas produces andosols, rich in allophane and ferrihydrite. Since the rate of mineral formation is very useful in climate and geochemical modelling, this study investigates Si isotope compositions of allophane as a proxy for mineral formation. Allophane formed in contrasting conditions in five Icelandic soil profiles displays silicon isotope signatures lighter than the basalt in less weathered soils (-0.64 ± 0.15‰), and heavier in more weathered organic-rich soils (+0.23 ± 0.10‰). The fate of the dissolved Si in those volcanic soils strongly depends on Al availability. In organic-rich soils, most of Al is humus-complexed, and the results support that Si precipitates as opaline silica by super-saturation, leaving an isotopically heavier dissolved Si pool to form allophane with uncomplexed Al. This study highlights that Si isotopes can be useful to record successive soil processes involved in mineral formation, which is potentially useful in environmental paleo-reconstruction.

Original language	English
Pages (from-to)	S115-S118
Journal	Applied Geochemistry
Volume	26
Issue number	SUPPL.
DOIs	https://doi.org/10.1016/j.apgeochem.2011.03.044
Publication status	Published - Jun 2011

Bibliographical note

Funding Information: We thank N. Belshaw, F. Mokadem, A. Mason and S. Wyatt for their help in the isotope geochemistry laboratory (University of Oxford, UK), A. Iserentant, C. Givron, A. Lannoye, P. Populaire and W. Nguefack for their contribution on the soil characterization (Université catholique de Louvain, Belgium). S.O. is funded by the “Fonds National de la Recherche Scientifique” (Belgium) and acknowledges a funding from FSR (Fonds Special de Recherche, UCL, Belgium). Funding for the analyses at Oxford was provided by grants from the Science and Technology Research Council and the European Research Council.

Access to Document

10.1016/j.apgeochem.2011.03.044

Cite this

@article{47d34ac3da264dd3af85153f8a70f3bf,

title = "Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils",

abstract = "Weathering of basaltic ash in volcanic areas produces andosols, rich in allophane and ferrihydrite. Since the rate of mineral formation is very useful in climate and geochemical modelling, this study investigates Si isotope compositions of allophane as a proxy for mineral formation. Allophane formed in contrasting conditions in five Icelandic soil profiles displays silicon isotope signatures lighter than the basalt in less weathered soils (-0.64 ± 0.15‰), and heavier in more weathered organic-rich soils (+0.23 ± 0.10‰). The fate of the dissolved Si in those volcanic soils strongly depends on Al availability. In organic-rich soils, most of Al is humus-complexed, and the results support that Si precipitates as opaline silica by super-saturation, leaving an isotopically heavier dissolved Si pool to form allophane with uncomplexed Al. This study highlights that Si isotopes can be useful to record successive soil processes involved in mineral formation, which is potentially useful in environmental paleo-reconstruction.",

author = "S. Opfergelt and Georg, \{R. B.\} and Burton, \{K. W.\} and R. Guicharnaud and C. Siebert and Gislason, \{S. R.\} and Halliday, \{A. N.\}",

note = "Funding Information: We thank N. Belshaw, F. Mokadem, A. Mason and S. Wyatt for their help in the isotope geochemistry laboratory (University of Oxford, UK), A. Iserentant, C. Givron, A. Lannoye, P. Populaire and W. Nguefack for their contribution on the soil characterization (Universit{\'e} catholique de Louvain, Belgium). S.O. is funded by the “Fonds National de la Recherche Scientifique” (Belgium) and acknowledges a funding from FSR (Fonds Special de Recherche, UCL, Belgium). Funding for the analyses at Oxford was provided by grants from the Science and Technology Research Council and the European Research Council.",

year = "2011",

month = jun,

doi = "10.1016/j.apgeochem.2011.03.044",

language = "English",

volume = "26",

pages = "S115--S118",

journal = "Applied Geochemistry",

issn = "0883-2927",

publisher = "Elsevier Ltd.",

number = "SUPPL.",

}

TY - JOUR

T1 - Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils

AU - Opfergelt, S.

AU - Georg, R. B.

AU - Burton, K. W.

AU - Guicharnaud, R.

AU - Siebert, C.

AU - Gislason, S. R.

AU - Halliday, A. N.

N1 - Funding Information: We thank N. Belshaw, F. Mokadem, A. Mason and S. Wyatt for their help in the isotope geochemistry laboratory (University of Oxford, UK), A. Iserentant, C. Givron, A. Lannoye, P. Populaire and W. Nguefack for their contribution on the soil characterization (Université catholique de Louvain, Belgium). S.O. is funded by the “Fonds National de la Recherche Scientifique” (Belgium) and acknowledges a funding from FSR (Fonds Special de Recherche, UCL, Belgium). Funding for the analyses at Oxford was provided by grants from the Science and Technology Research Council and the European Research Council.

PY - 2011/6

Y1 - 2011/6

N2 - Weathering of basaltic ash in volcanic areas produces andosols, rich in allophane and ferrihydrite. Since the rate of mineral formation is very useful in climate and geochemical modelling, this study investigates Si isotope compositions of allophane as a proxy for mineral formation. Allophane formed in contrasting conditions in five Icelandic soil profiles displays silicon isotope signatures lighter than the basalt in less weathered soils (-0.64 ± 0.15‰), and heavier in more weathered organic-rich soils (+0.23 ± 0.10‰). The fate of the dissolved Si in those volcanic soils strongly depends on Al availability. In organic-rich soils, most of Al is humus-complexed, and the results support that Si precipitates as opaline silica by super-saturation, leaving an isotopically heavier dissolved Si pool to form allophane with uncomplexed Al. This study highlights that Si isotopes can be useful to record successive soil processes involved in mineral formation, which is potentially useful in environmental paleo-reconstruction.

AB - Weathering of basaltic ash in volcanic areas produces andosols, rich in allophane and ferrihydrite. Since the rate of mineral formation is very useful in climate and geochemical modelling, this study investigates Si isotope compositions of allophane as a proxy for mineral formation. Allophane formed in contrasting conditions in five Icelandic soil profiles displays silicon isotope signatures lighter than the basalt in less weathered soils (-0.64 ± 0.15‰), and heavier in more weathered organic-rich soils (+0.23 ± 0.10‰). The fate of the dissolved Si in those volcanic soils strongly depends on Al availability. In organic-rich soils, most of Al is humus-complexed, and the results support that Si precipitates as opaline silica by super-saturation, leaving an isotopically heavier dissolved Si pool to form allophane with uncomplexed Al. This study highlights that Si isotopes can be useful to record successive soil processes involved in mineral formation, which is potentially useful in environmental paleo-reconstruction.

UR - https://www.scopus.com/pages/publications/79955964495

U2 - 10.1016/j.apgeochem.2011.03.044

DO - 10.1016/j.apgeochem.2011.03.044

M3 - Article

SN - 0883-2927

VL - 26

SP - S115-S118

JO - Applied Geochemistry

JF - Applied Geochemistry

IS - SUPPL.

ER -

Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils

Abstract

Bibliographical note

Access to Document

Fingerprint

Cite this