Introduction of or replacement by a zeolite mineral.



a process in which feldspathic rocks are replaced by zeolites, occurring under conditions of relatively low temperatures and pressures by the action of hydrothermal solutions. Zeolitization is one of the forms of the metamorphism of rocks under conditions of zeolite facies. Basic effusive rocks are most frequently zeolitized, either fully or partially. Crystals of zeolites and other hydrothermal minerals, such as calcite, apophyllite, and analcime, form in the cavities of such rocks.

Zeolitized rocks are developed extensively in regions of ancient volcanic activity; modern zeolitization processes are observed in volcanic regions at sites where thermal waters seep out, for example at Paratunka and Pauzhetka on Kamchatka in the USSR and at various places in New Zealand and Iceland. Deposits of Iceland spar are associated with rocks that have been zeolitized. Individual layers of volcanic ash that have undergone zeolitization and are composed entirely of zeolites are used in industry as a cement additive and a valuable adsorbent.

References in periodicals archive ?
As uranium start to deposit in reducing environment so the plant remains in host rocks are replaced by iron oxides and other minor alterations like argillization, sericitization, calcitization, sulfidization, zeolitization, baritization etc.
cation also plays a very important role during zeolitization, because it stabilizes the sub-building units of zeolite frameworks and is fundamental for zeolite synthesis under hydrothermal conditions (Fernandez-Jimenez et al.
Hierarchical Pore Structures through Diatom Zeolitization.
Zeolitization of a bentonite and its application to the removal of ammonium ion from waste water.
The leached aluminum has dual roles during zeolite membrane growth: to facilitate the formation of the gel layer on the substrate and to retard zeolitization in this gel layer.
At this concentration the degree of zeolitization was expressed as the decrease in the intensity of quartz and feldspar peaks between 30 and 35[degrees] [16].
The process of oil shale ash zeolitization was studied at the experimental conditions: 8 M sodium hydroxide solution, 160[degrees]C and reaction time 1-24 h.
Conditions favouring zeolitization occurred in a terrestrial lava flow of amygdaloidal trachyandesite, which belongs among volcanic products of the Ceske stfedohofi Mts.
The upper part of the lava flow became vesicular and scoriaceous due to lava degassing, and strongly affected by postmagmatic zeolitization evidencing volatile-phase activity after the eruption.
The oldest basaltic clasts in the McCoy Brook Formation contain a similar mineral assemblage (including sparse "heulandite" and chabazire) in amygdales, suggesting that the oldest zeolitization predated erosion of the clasts at fault scarps in the basalt.
The oldest basaltic clasts in the McCoy Brook Formation contain sparse zeolite in amygdales even where matrix zeolite is absent, suggesting that the oldest zeolitization predated erosion of the clasts at fault scarps in the basalt, However, the predominant zeolitization appears to affect the McCoy Brook Formation and the North Mountain Basalt equally.
Zeolitization of geological and waste materials at low temperature in KOH solutions.