Hostname: page-component-745bb68f8f-cphqk Total loading time: 0 Render date: 2025-01-25T22:32:03.523Z Has data issue: false hasContentIssue false
  • English
  • Français

The mineralogy, texture and significance of silica derived from alteration by steam condensate in three New Zealand geothermal fields

Published online by Cambridge University Press:  09 July 2018

K. A. Rodgers ,
K. L. Cook ,
P. R. L. Browne  and
K. A. Campbell
K. A. Rodgers*
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, AucklandNew Zealand
K. L. Cook
Affiliation:
California Institute of Technology, 1201 E. California, Pasedena, CA 91126, USA
P. R. L. Browne*
Affiliation:
Geothermal Institute, University of Auckland, Private Bag 92019, AucklandNew Zealand
K. A. Campbell*
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, AucklandNew Zealand
*
†Australian Museum, SydneyNSW 2000, Australia
*E-mail:, prl.browne@auckland.ac.nz
‡California Academy of Sciences, San Francisco, CA 94118, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Opaline silica residue accumulates on the surface and in the near surface of the Te Kopia, Tikitere and Rotokawa geothermal fields, where rhyolitic tuffs are attacked by steam condensate, made acid (pH 2–3) by sulphuric acid produced by oxidation of H2S that accompanies steam discharge. Silica residue is one product of this alteration process that also yields kaolinite, sulphur, sulphide and aluminous sulphates, including alunite and alunogen, as pH, Eh and available moisture fluctuate across the field surface. Coagulation of colloidal polymeric silica or, possibly, direct deposition of monomeric silica can occur from the acid solutions of the digested country rock, depending on pH, concentration, temperature and the presence and concentration of other species. As with silica sinter, the first-formed silica phase consists of disordered opal-A microspheroids, commonly 0.1–5 μm in diameter. These coalesce and become overgrown by further opaline silica to yield a mass resembling gelatinous ‘frog spawn’ that lines cavities and envelops surfaces. This mass is the principle component of botryoidal, transparent to translucent hyalite that comprises much residue. Following deposition, this juvenile residue may crystallize to opal-CT lepispheres, 1–3 μm across and, subsequently, to chalcedonic quartz. Both the opal-A and opal-CT of the New Zealand residues are more disordered than those occurring in typical moderate- to low-temperature sinters. The opaline silica of silica residues enjoys a reaction relationship with both kaolinite and aluminium sulphates, including alunite and alunogen. These phases and the silica precipitate continuously and undergo dissolution at the surface of all three localities. The precise pathway followed depends upon the prevailing surface conditions, including humidity, pH, Eh, and Al and K activities. As Al is flushed from the system, the ultimate stage of alteration that may result is the dissolution of the silica itself in acidified rainwater, fogdrip or further steam condensate.

Keywords

opaline silicaalterationgeothermal fieldsteam condensateNew Zealand
Type
Research Article
Information
Clay Minerals , Volume 37 , Issue 2 , June 2002 , pp. 299 - 322
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2002

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bigham, J.M., Schwertmann, U. & Carlson, L. (1992) Mineralogy of precipitates formed by the biogeochemical oxidation of Fe(II) in mine drainage. Pp. 219–232 in: Biomineralization Processes of Iron and Mangane se (Skinner, H.C.W. & Fitzpatrick, R.W., editors). Catena Verlag, Crelingen- Dedst, Catena Supplement 21.Google Scholar
Bignall, G. & Browne, P.R.L. (1994) Surface hydrothermal alteration and evolution of the Te Kopia thermal area, New Zealand. Geothermics, 26, 645–658.Google Scholar
Campbell, K.A., Sannazzaro, K., Browne, P.R.L., Herdianita, N.R. & Rodgers, K.A. (2001) Sedimentary facies and mineralogy of the Late Pleistocene Umukuri silica sinter, Taupo Volcanic Zone, New Zealand. Journal of Sedimentary Research, 71, 728–747.CrossRefGoogle Scholar
Dove, P.M. & Rimstidt, J.D. (1994) Silica-water interactions. Pp. 259–308 in: Silica: Physical Behavior, Geochemistry and Materials Applications (Heaney, P.J., Prewitt, C.T. & Gibbs, G.V., editors). Reviews in Mineralogy, 29, Mineralogical Society of America, Washington, D.C.Google Scholar
Fortin, D. & Beveridge, T.J. (1997) Role of bacterium Thiobacillus in the formation of silicates in acidic mine tailings. Chemical Geology, 141, 235–250.CrossRefGoogle Scholar
Gíslason, S., Heaney, P. Oelkers, E. & Schott, J. (1997) Kinetic and thermodynamic properties of moganite, a nove l si lica polymorph. Geochimica et Cosmochimica Acta, 61, 1193–1204.Google Scholar
Glover, R.B. (1974) Geochemistry of the Rotorua geothermal district. Pp. 79–113 in: Geothermal resources survey, Rotorua geothermal district. Geothermal Report, 6, Department of Scientific and Industrial Research New Zealand.Google Scholar
Grange, L.I. (1937) The geology of the Rotorua-Taupo subdivisio n. New Zealand Geological Survey Bulletin, 37, 1–138.Google Scholar
Harder, H. & Flehmig, W. (1967) Quartzsynthese bei tiefen Tmeperaturen. Geochimica et Cosmochimica Acta, 34, 295–305.Google Scholar
Harding, R.D. (1971) Stability of silica dispersions. Journal of Colloidal Interface Science, 35, 172–174.CrossRefGoogle Scholar
Heaney, P.J. & Post, J.E. (1992) The widespread distribution of a novel silica polymorph in microcrystalline quartz varieties. Science, 255, 441–443.Google Scholar
Hem, J.D., Roberson, C.E., Lind, J.C. & Polzer, W.L. (1973) Chemical interactions of aluminium species with aqueous silica at 25°C. US Geological Survey Water Supply Paper 1827-E.Google Scholar
Herdianita, N.R. (1996) Characteristics of silica sinter deposited from thermal waters.Unpublished MSc manuscript, University of Auckland Library.Google Scholar
Herdianita, N.R., Browne, P.R.L., Rodgers, K.A. & Campbell, K.A. (2000a) Mineralogical and morphological changes accompanying ageing of siliceous sinter and silica residue. Mineralium Deposita, 35, 48–62.Google Scholar
Herdianita, N.R., Rodgers, K.A. & Browne, P.R.L. (2000b) Routine procedures to characterise the mineralogy of modern and ancient silica sinter deposits. Geothermics, 29, 367–375.Google Scholar
Hopkinson, L., Roberts, S., Herrington, R. & Wilkinson, J. (1999) The nature of crystalline silica from the TAG submarine hydrothermal mound, 26 degrees N Mid Atlantic Ridge. Contributions to Mineralogy and Petrology, 137, 342–350.CrossRefGoogle Scholar
Iler, R.K. (1979) The Chemistry of Silica: Solubility, Polymerization, Colloid and Surface Properties, and Biochemistry. Wiley-Interscience, New York, 866 pp.Google Scholar
Kaplan, I.R. (1956) Evidence of microbiological activity in some of the geothermal regions of New Zealand. New Zealand Journal of Science and Technology, 37, 639–662.Google Scholar
Krupp, R., Browne, P.R.L., Henley, R.W. & Seward, T.M. (1986) Rotokawa geothermal field. Pp. 47–55 in. Monograp h series on Mineral Deposits, 26. Gebrüder Borntrager, Berlin-Stuttgart, Germany.Google Scholar
Martin, R., Rodgers, K.A. & Browne, P.R.L. (1999) The nature and significance of sulphate-rich, aluminous efflorescences from the Te Kopia geothermal field, Taupo Volcanic Zone, New Zealand. Mineralogical Magazine, 63, 413–419.Google Scholar
Martin, R., Rodgers, K.A. & Browne, P.R.L. (2000a) Aspects of the distribution and movement of aluminium in the surface of the Te Kopia geothermal field, Taupo Volcanic Zone, New Zealand. Applied Geochemistry, 15, 1121–1136.Google Scholar
Martin, R., Mildenhall, D., Browne, P.R.L. & Rodgers, K.A. (2000b) The age and significance of in-situ sinter at Te Kopia thermal area. Geothermics, 29, 367–375.Google Scholar
Moore, J.N. & Nielson, D.L. (1994) An overview of the geology and geochemistry of the Roosevelt Hot Springs geothermal system, Utah. Pp. 25–36 in. Cenozoic Geology and Geothermal Systems of southwestern Utah (Blackett, R.E. & Moore, J.N., editors). Utah Geological Association Publication, 23, Utah, USA.Google Scholar
Murata, K.L. & Nakata, K. (1974) Cristobalitic stage in the diagenesis of diatomaceous shale. Science, 184, 567–568.Google Scholar
Nordstrom, D.K. (1982). The effect of sulfate on aluminium concentrations in natural waters: some stability relations in the system Al2O3 SO3 H2O at 298 K. Geochimica et Cosmochimica Acta, 46, 681–692.CrossRefGoogle Scholar
Pastars, D. (2000) Mineralogy and microfacies of the Late Pleistocene Omapere silica sinter, Northland, New Zealand. Unpublished MSc manuscript, University of Auckland Library.Google Scholar
Ramahashay, B.C. (1968) A geochemical study of rock alteration by hot springs in the Paint Pot Hill area, Yellowstone Park. Geochimica et Cosmochimica Acta, 32, 499–522.CrossRefGoogle Scholar
Rodgers, K.A. (2000) Research on silica sinters. Mineralogical Society Bulletin, 126 (April), 16–17.Google Scholar
Rodgers, K.A. & Cressey, G. (2001) The occurrence, detection and significance of moganite (SiO2) among some silica sinters. Mineralogical Magazine, 65, 293–303.Google Scholar
Rodgers, K.A., Hamlin, K.A., Browne, P.R.L., Campbell, K.A. & Martin, R. (2000) The steam condensate alteration mineralogy of Ruatapu cave, Orakei Korako geothermal field, Taupo Volcanic Zone, New Zealand. Mineralogical Magazin e, 64, 125–142.Google Scholar
Schoen, R., White, D.E. & Hemley, J.J. (1974) Argillization by descending acid at Steamboat Springs, Nevada. Clays and Clay Minerals, 22, 1–22.Google Scholar
Smith, D.K. (1997) Evaluation of the detectability and quantification of respirable crystalline silica by X-ray powder diffraction. Powder Diffraction, 12, 200–227.Google Scholar
Smith, D.K. (1998) Opal, cristobalite, and tridymite: noncrystallinity versus crystallinity, nomenclature of the silica minerals and bibliography. Powder Diffraction, 13, 2–19.Google Scholar
Teece, C. (2000) Sinters deposited from acid-sulphatechloride waters at the Rotokawa geothermal field (Taupo Volcanic Zone, New Zealand). Unpublished MSc manuscript, University of Auckland Library.Google Scholar
White, D.E., Branock, W.W. & Murata, K.J. (1956) Silica in hot spring waters. Geochimica et Cosmochimica Acta, 10, 27–59.Google Scholar
White, D.E., Hutchinson, R.A. & Keith, T.E.C (1988) The geology and remarkable thermal activity of Norris Geyser Basin, Yel lowstone National Park, Wyoming. US Geological Survey Professional Paper 1456, 1–84.Google Scholar