HRTEM of microcrystalline opal in chert and porcelanite from the Monterey Formation, California

  title={HRTEM of microcrystalline opal in chert and porcelanite from the Monterey Formation, California},
  author={S. Cady and H. Wenk and K. Downing},
  journal={American Mineralogist},
  pages={1380 - 1395}
Abstract Microcrystalline opal was investigated using low-dose transmission electron microscopy (TEM) methods to identify microstructural characteristics and possible phase-transformation mechanisms that accommodate silica diagenesis. High-resolution TEM (HRTEM) revealed that microcrystalline opal in opal-CT chert (>90 wt% silica) and opal-CT porcelanite (50-90 wt% silica) from the Miocene Monterey Formation of California displays various amounts of structural disorder and coherent and… Expand

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