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The occurrence, detection and significance of moganite (SiO2) among some silica sinters

Published online by Cambridge University Press:  05 July 2018

K. A. Rodgers  and
G. Cressey
K. A. Rodgers*
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019 Auckland, New Zealand
G. Cressey
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
*
*E-mail: ka.rodgers@auckland.ac.nz
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Abstract

Moganite, monoclinic SiO2, is a component of microcrystalline, quartz-bearing, sinters of New Zealand derived from crystallization of non-crystalline and paracrystalline opaline silicas. It occurs at levels of <13 vol.% of the SiO2 phases present in sinters between 20,000 and 200,000 y old but is generally either absent or below the level of detection in Tertiary sinters. Unambiguous identification of moganite is most readily accomplished by laser Raman spectroscopy; the technique allows individual microtextural elements of a sinter's fabric to be analysed. Conventional scanning X-ray powder diffraction procedures are limited in their ability to discern the characteristic moganite diffraction lines from the very similar quartz pattern, especially in those samples where moganite is at low concentration and/or unanticipated. However, powder diffraction, using a position-sensitive detector system, allows not only the identification of the moganite pattern in the presence of a large proportion of quartz, but also semiquantitative estimates of the different silica phases present in bulk sinter samples of ~450 mg. Moganite is part of the sinter maturation sequence. It occurs as a metastable phase that will ultimately transform to quartz, given sufficient time or a change in ambient conditions.

Keywords

moganitequartzsilicasinterRamanposition-sensitive detector
Type
Research Article
Information
Mineralogical Magazine , Volume 65 , Issue 2 , April 2001 , pp. 157 - 167
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

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References

Batchelder, M. and Cressey, G. (1998) Rapid, accurate phase quantification of clay-bearing samples using a position-sensitive detector. Clays Clay Miner., 46, 183–94.CrossRefGoogle Scholar
Bates, J.B. (1972) Raman spectra of α and β cristobalite. J. Chem. Phy. 57, 4042–7.CrossRefGoogle Scholar
Brindley, G.W. (1980) Quantitative X-ray mineral analys is of clays. Pp. 411–38 in: Crystal Structures of Clay Minerals and their X-ray Identificatio. (Brindley, G.W. and Brown, G., editors). Monograph, 5. Mineralogical Society, London.Google Scholar
Cressey, G. and Schofield, P.F. (1996) Rapid whole-pattern profile-stripping methofifor the quantification of multiphase samples. Powder Diffraction., 11, 35–9.CrossRefGoogle Scholar
Flörke, O.W., Jones, J.B. and Schmincke, H.-U. (1976) A new microcrystalline silica from Gran Canaria. Zeits. Kristallogr., 143, 156–65.Google Scholar
Flörke, O.W., Flörke, U. and Giese, U. (1984) Moganite: a new microcrystalline mineral. Neues Jahrb. Mineral. Abh., 149, 325–36.Google Scholar
Frondel, C. (1962) The System of Mineralogy, Vol III Silica Mineral. 7th edition, Wiley & Sons, New York.Google Scholar
Gíslason, S., Heaney, P., Oelkers, E. and Schott, J. (1997) Kinetic and thermodynamic properties of moganite, a novel silica polymorph. Geochim. Cosmochim. Acta, 61, 1193–204.CrossRefGoogle Scholar
Götze, J., Nasdala, L., Kleeberg, R. and Wenzel, M. (1998) Occurrence and distribution of “moganite” in agate/chalcedony: a combined micro-Raman, Rietveld and cathodoluminescence study. Contrib. Mineral. Petrol., 133, 96–105.CrossRefGoogle Scholar
Guthrie, G.D., Bish, D.L. and Reynolds, R.C. (1995) Modelling the X-ray diffraction pattern of opal-CT. Amer. Mineral., 80, 869–72.CrossRefGoogle Scholar
Heaney, P.J. and Post, J.E. (1992) The widespread distribution of a novel silica polymorph in microcrystalline quartz varieties. Science, 255, 441–3.CrossRefGoogle ScholarPubMed
Herdianita, N.R., Rodgers, K.A. and Browne, P.R.L. (2000 a) Routine procedures to characterise the mineralogy of modern and ancient silica sinter deposits. Geothermics., 29, 367–75.CrossRefGoogle Scholar
Herdianita, N.R., Browne, P.R.L., Rodgers, K.A. and Campbell, K.A. (2000 b) Mineralogical and morphological changes accompanying aging of siliceous sinter and silica residue. Mineral. Deposita., 35, 48–62.CrossRefGoogle Scholar
Jayaraman, A., Wood, D.L. and Maines, R.G. (1987) High pressure Raman study of the vibrational modes in AlPO4 and SiO2 (quartz). Phys. Rev. B, 35, 8316–21.CrossRefGoogle Scholar
Kano, K. (1983) Ordering of opal-CT in diagenesis. Geochem. J., 17, 87–93.CrossRefGoogle Scholar
Kingma, K.J. and Hemley, R.J. (1994) Raman spectroscopic study of microcrystalline silica. Amer. Mineral., 79, 269–73.Google Scholar
Langer, K. and Flörke, O.W. (1974) Near infrared absorption spectra (4000 to 9000 cm−1) of opals and the role of “water” in these SiO2.nH2O minerals. Fortschr. Miner., 52, 17–51.Google Scholar
Miehe, G. and Graetsch, H. (1992) Crystal structure of moganite: a new structure type for silica. Eur. J. Mineral., 4, 693–706.CrossRefGoogle Scholar
Miehe, G., Graetsch, H. and Flörke, O.W. (1984) Crystal structure and growth fabric of length fast chalcedony. Phys. Chem. Miner., 10, 197–9.CrossRefGoogle Scholar
Miehe, G., Graetsch, H., Flörke, O.W. and Fuess, H. (1988) The monoclinic crystal structure of the SiO2-mineral moganite. Zeits. Kristallogr., 182, 183–4.Google Scholar
Murata, K.L. and Nakata, K. (1974) Cristobalitic stage in the diagenesis of diatomaceous shale. Science, 184, 567–8.CrossRefGoogle ScholarPubMed
Sannazzaro, K., Campbell, K.A., Browne, P.R.L., Herdianita, N.R. and Rodgers, K.A. (in press) Sedimentary facies and mineralogy of the Late Pleistocene Umukuri silica sinter, Taupo Volcanic Zone, New Zealand. J. Sed. Re. Google Scholar
Smith, D.K. (1997) Evaluation of the detectability and quantification of respirable crystalline silica by X-ray powder diffraction. Powder Diffraction., 12, 200–27.CrossRefGoogle Scholar
Smith, D.K. (1998) Opal, cristobalite, and tridymite: noncrystallinity versus crystallinity, nomenclature of the silica minerals and bibliography. Powder Diffraction., 13, 2–19.CrossRefGoogle Scholar
White, D.E., Hutchinson, R.A. and Keith, T.E.C. (1988) The geology and remarkable thermal activity of Norris Geyser Basin, Yellowstone National Park, Wyoming. US Geol. Surv. Prof. Paper, 1456, 1–84.Google Scholar