Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-07T05:18:38.323Z Has data issue: false hasContentIssue false
  • English
  • Français

Formation of coagulated colloidal silica in high-temperature mineralizing fluids

Published online by Cambridge University Press:  05 July 2018

B. J. Williamson ,
J. J. Wilkinson ,
P. F. Luckham  and
C. J. Stanley
B. J. Williamson*
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
J. J. Wilkinson
Affiliation:
Department of Earth Science and Engineering, Imperial College, Prince Consort Road, London SW7 2BP, UK
P. F. Luckham
Affiliation:
Department of Chemical Engineering, Imperial College, Prince Consort Road, London SW7 2BY, UK
C. J. Stanley
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Recent experimental studies have suggested that colloidal silica can form in high-T (300 to >700°C) hydrothermal fluids (Wilkinson et al., 1996). Natural evidence in support of this was found by Williamson et al. (1997) who proposed a colloidal (gel) silica origin for <50 μm irregularly-shaped inclusions of quartz contained in greisen topaz from southwest England. Confocal and microprobe studies, presented here, strengthen this argument although rather than forming a gel in the hydrothermal fluid, it is suggested that the colloidal silica aggregated as a viscous coagulated colloid, with much of its volume (<10 to 30 vol.%) consisting of metal (mainly Fe) -rich particles. This is evident from the largely solid nature of metal-rich shrinkage bubbles contained at the margins of the inclusions of quartz which shows that the material forming the inclusions contained much less liquid than would be expected in a silica gel. These findings may have important implications for models of ore formation since the precipitation of a coagulated colloid could inhibit hydrothermal fluid transport and cause co-deposition of silica and entrained ore-forming elements. The mode of formation of the colloidal silica and further implications of the study are discussed.

Keywords

silicacolloidhydrothermalore genesissupercritical fluids
Type
Research Article
Information
Mineralogical Magazine , Volume 66 , Issue 4 , August 2002 , pp. 547 - 553
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

Alderton, D.H.M. and Harmon, R.S. (1991) Fluid inclusion and stable isotope evidence for the origin of mineralizing fluids in south-west England. Mineralogical Magazine, 55, 605–611.CrossRefGoogle Scholar
Alderton, D.H.M. and Rankin, A.H. (1983) The character and evolution of hydrothermal fluids associated with the kaolinised St. Austell granite, SW England. Journal of the Geological Society of London, 140, 297–310.CrossRefGoogle Scholar
Bray, C.J. and Spooner, E.T.C. (1983) Sheeted vein Sn-W mineralization and greisenization associated with economic kaolinization, Goonbarrow China Clay Pit, St. Austell, Cornwall, England: Geologic relationships and geochronology. Economic Geology, 78, 1064–1089.CrossRefGoogle Scholar
Eadington, P.J. and Nashar, B. (1978) Evidence for the magmatic origin of quartz-topaz rocks from the New England Batholith, Australia. Contributions to Mineralogy and Petrology, 67, 433–438.CrossRefGoogle Scholar
Herrington, R.J. and Wilkinson, J.J. (1993) Colloidal gold and silica in mesothermal vein systems. Geology, 21, 539–542.2.3.CO;2>CrossRefGoogle Scholar
Hopkinson, L., Roberts, S., Herrington, R. and Wilkinson, J. (1998) Self-organization of submarine hydrothermal siliceous deposits: Evidence from the TAG hydrothermal mound, 26°N Mid-Atlantic Ridge. Geology, 26, 347–350.2.3.CO;2>CrossRefGoogle Scholar
Hopkinson, L.J., Dee, S. and Boulter, C.A. (2000) Moving reactive interfaces and fractal carbonate replacement patterns in serpentinites: Evidence from the southern Iberia abyssal plain. Mineralogical Magazine, 64, 791–800.CrossRefGoogle Scholar
Iler, R.K. (1979) The Chemistry of Silica. John Wiley, New York.Google Scholar
Jones, R.W. (1989) Fundamental Principles of Sol-Gel Technology. Institute of Metals, London, UK.Google Scholar
Rankin, A.H. and Alderton, D.H.M. (1985) Fluids in granites from southwest England. Pp. 287–299 in: High Heat Production (HHP) Granites, Hydrothermal Circulation and Ore Genesis. Institution of Mining and Metallurgy, London.Google Scholar
Saunders, J.A. (1990) Colloidal transport of gold and silica in epithermal precious-metal systems : Evidence from the Sleeper deposit, Nevada. Geology, 18, 757–760.2.3.CO;2>CrossRefGoogle Scholar
Smith, J.V. and Steele, I.M. (1984) Chemical substitution in silica polymorphs. Neues Jahrbuch für Mineralogie Monatshefte, 137–144.Google Scholar
Sourirajan, S. and Kennedy, G.C. (1962) The system H2O-NaCl at elevated temperatures and pressures. American Journal of Science, 260, 115–141.CrossRefGoogle Scholar
Wilkinson, J.J., Nolan, J. and Rankin, A.H. (1996) Silicothermal fluid: a novel medium for mass transport in the lithosphere. Geology, 24, 1059–1062.2.3.CO;2>CrossRefGoogle Scholar
Williamson, B.J., Stanley, C.J. and Wilkinson, J.J. (1997) Implications from inclusions in topaz for greisenisation and mineralisation in the Hensbarrow topaz granite, Cornwall, England. Contributions to Mineralogy and Petrology, 127, 119–128.CrossRefGoogle Scholar
Yucheng, L. (1989) Comparative aspects of pegmatitic and pneumatolytic evolution of Cornish granites. PhD thesis, Royal School of Mines, Imperial College of Science, Technology and Medicine, University of London, p. 247.Google Scholar
Yucheng, L., Halls, C. and Spiro, B. (1989) Fluid evolution and isotopic compositions in pegmatites and pneumatolytic lodes from the St. Austell Granite, SW England, UK. Abstract, ECROFI X (European Current Research on Fluid Inclusions) Symposium, London, p. 98.Google Scholar
Zaraiskii, G.P. (1999) The conditions of the nonequilibrium silicification of rocks and quartz vein formation during acidic metasomatism. Geology of Ore Deposits, 41, 262–275. [English translation of Russian article in Geologiya Rudnykh Mestorozhdenii, 41, 294–307.Google Scholar