Porcellanite in the Mishash Formation, Negev, southern Israel
Kolodny, Y.; Nathan, Y.; Sass, E.
Journal of Sedimentary Petrology 35(2): 454-463
ISSN/ISBN: 0022-4472 Accession: 019748830
The porcellanite occurs in association with chert in the lower part of the Mishash formation (Cretaceous). It is composed mostly of opal and is highly porous. It is believed to have formed by diagenesis in a semiclosed basin in the vicinity of a continent with low relief, under tropical climatic conditions in an environment in which pH determined whether opal or quartz formed.