phyllic alteration

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  • Info Phyllic alteration is an alteration zone in a permeable rock that has been affected by circulation of hydrothermal fluids. more...
  • Phyllic alteration typically forms in the base-metal zone of a porphyry system.
  • Argillic grades into phyllic alteration at higher temperatures in an ore deposit hydrothermal system.
  • Phyllic alteration is often closely associated with argillic alteration, which occurs at lower temperatures and dominantly affects plagioclase.
  • If a rock undergoes phyllic alteration, then orthoclase feldspar, biotite and various silicates are altered in addition to plagioclase.
  • Hydrogen-ion metasomatism is the process that causes phyllic alteration.
  • Sericitic alteration occurs within the phyllic alteration zone.