Prehnite-pumpellyite facies
4212579
57900715
2006-06-10T17:34:26Z
Bluebot
527862
Unicodifying using [[Wikipedia:AutoWikiBrowser|AWB]]
The '''prehnite-pumpellyite facies''' is a [[Metamorphism|metamorphic facies]] typical of subseafloor alteration of the [[oceanic crust]] around [[mid-ocean ridge]] spreading centres.
<!-- Unsourced image removed: [[Image:Metamorphic Facies.JPG|thumb|300px|Metamorphic facies]] -->
It is a metamorphic grade transitional between [[zeolite facies]] and [[greenschist facies]] representing a temperature range of 250 to 350 °C and a pressure range of approximately two to seven kilobars. The mineral assemblage is dependent on host composition.
*In [[mafic]] rocks the assemblage is [[Chlorite group|chlorite]], [[prehnite]], [[albite]], [[pumpellyite]] and [[epidote]].
*In [[ultramafic]] rocks the assemblage is [[serpentine]], [[talc]], [[forsterite]], [[tremolite]] and chlorite.
*In argillaceous sedimentary rocks the assemblage is [[quartz]], [[illite]], albite, and [[stilpnomelane]] chlorite.
*In carbonate sediments the assemblage is [[calcite]], [[dolomite]], quartz, [[Clay minerals|clays]], talc, and [[muscovite]].
==References==
* Blatt, Harvey and Robert Tracy, 1995, ''Petrology: igneous, sedimentary, and metamorphic'', Freeman, ISBN 0-7167-2438-3
{{Metamorphic Facies}}
[[Category:Metamorphic rocks]]
[[Category:Petrology]]
{{geology-stub}}