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Stilbite-Mordenite zone

Chemical Process (Alteration) - Open system under ground (Alkaline metasomatism)

Correlated: Low-T zeolite facies


Zeolite zone

Index Minerals

Stilbite, Mordenite

Required Geological Setting

Metasomatic rocks (Alkaline)


Metasomatic zone formed by alkaline hydrothermal fluid of 50-100 degree associated with Basaltic magma activities. This alteration is a part of Zeolitization. Stilbite-Mordenite zone may be associated with Hydrothermal Au-Ag deposits. The water related to the alteration reaction of the stilbite-mordenite zone is meteoric water and/or magmatic water, and the water/rock ratio is more than a few tens times. It means that minerals were formed by reactions of the open system. On the other hand, the water related to the diagenesis is interstitial water in sediments, and the water/rock ratio is less than ten times. Minerals by diagenesis were formed by reactions of the closed system.

Change of mineral assemblages

  • [ Appear ] Stilbite, Mordenite, Chabazite

Mineral Assemblages

  • [ Felsic Rocks ] Stilbite, Chabazite, (Calcite)
  • [ Mafic Rocks ] Mordenite, Chabazite, (Calcite)


Related Occurrences

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