Precipitation of silica minerals in hydrothermal flow-through experiments

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Hydrothermal flow-through experiments were conducted to investigate the mechanism of silica precipitation at 430°C, 31 MPa using the input solutions of CSi = ∼300 ppm (the degree of super-saturation, Ω = CSi/CSi, qtz, eq was ∼3). The mineralogy and occurrence of silica minerals changed depending on the Si concentration, substrate type, and additive cations (Na, K and Al). At near equilibrium conditions (Ω < 1.5), silica precipitation was restricted to overgrowth of substrate quartz. On the other hand, the mechanism was more complex in the higher Si concentration. In pure Si solution, the dominant silica mineral changed as opal-A → opal-C → quartz with decreasing Si concentration along the flow path, and stable minerals formed on next less stable phases. In multi-component solutions, quartz predominantly occurred in the entire parts of the vessel, indicating that the additive cations enhanced the direct nuclea-tion of quartz.

Original languageEnglish
Title of host publicationWater-Rock Interaction
PublisherCRC Press
Pages669-672
Number of pages4
ISBN (Electronic)9781439862995
ISBN (Print)9780415604260
Publication statusPublished - 2010 Jan 1

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

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  • Cite this

    Saishu, H., Okamoto, A., & Tsuchiya, N. (2010). Precipitation of silica minerals in hydrothermal flow-through experiments. In Water-Rock Interaction (pp. 669-672). CRC Press.