Low-temperature zeolite facies

Chemical Process (Solid-phase growth) - Burial Metamorphism (Low-T, Low-P)

Synonym

Early diagenesis

Index Minerals

Stilbite, Mordenite, Chabazite

Required Geological Setting

Occurrence

Metamorphic rocks formed by burial, regional, or contact metamorphism in the following condition: less than 100 degree and less than 0.3 GPa (10 km depth). Zeolite facies metamorphic rocks are in the transitional zone between diagenesis and metamorphism. Illite crystalinity 0.42 or vitrinite reflectance 2.0 may be used as the definition of the boundary between metamorphism and diagenesis. Based on this definition, the boundary between metamorphism and diagenesis is 200 degree and low-temperature zeolite facies and high-temperature zeolite facies are included in diagenesis.

Distribution of metamorphic rocks subjected to low-temperature zeolite facies metamorphism described in this site. Protolith of blue dots is bedded Mn deposit, and protoliths of green dots are igneous rocks and sedimentary rocks. Yellow zones are accretionary complexes.

Mineral Assemblages

[ Felsic Rocks ] Smectite, Celadonite, Quartz, Stilbite, Chabazite, (Calcite)
[ Mafic Rocks ] Smectite, Stilbite, Chabazite, Mordenite, (Calcite)
[ Ultramafic Rocks ] Serpentine (Chrysotile, Lizardite)
[ Mudstone ] Smectite, Quartz, Montmorillonite, Calcite
[ Laterite ]
[ Bedded Mn ] Braunite/Hausmannite, Caryopilite, Rhodochrosite, Quartz
[ Carbonate Rocks ] Calcite/Dolomite, Quartz