Review of stabilities of analcime and some calcium zeolites. [Stilbite, lawsonite, prebnite, laumontite, and wairakite]
Many laboratory experiments have been performed on the stabilities of analcime, stilbite, laumontite, wairakite, lawsonite and prehnite. Stabilities reported for most experiments in which fluid pressure equals 2 kb total pressure are: stilbite--less than 170/sup 0/C, laumontite--170/sup 0/ to 280/sup 0/C, and wairakite--280/sup 0/ to 385/sup 0/C. These three minerals are stable only below 3 kb fluid pressure. At higher fluid pressures, laumontite breaks down to lawsonite + quartz + H/sub 2/O, and wairakite reacts with H/sub 2/O to form prehnite + montmorillonite + quartz. Analcime + quartz together are stable below 4 kb and 200/sup 0/C. Under conditions where fluid pressure is less than total pressure, the stability fields of these zeolites are encroached by those of blueschist facies and prehnite-pumpellyite facies minerals in the higher pressure region and by those of greenschist facies minerals in the higher temperature region. At lower H/sub 2/O activities caused by dissolved substances, these zeolites would occur at lower P--T conditions than those determined by the experiments. For example, the upper stability temperature of laumontite is about 10/sup 0/C lower in an 0.25 N NaCl solution. Laumontite is stable in the CO/sub 2/-bearing fluid at 1 kb fluid pressure and 260/sup 0/C with maximum mol fraction of CO/sub 2/ of 0.023. At higher CO/sub 2/ contents, calcite + montmorillonite + quartz are stable. The stability data for these zeolites, together with our recent results on the relations of pumpellyite, prehnite-lawsonite, and wairakite-anorthite, permit delineation of the P--T paths for various observed mineral parageneses documented in the literature.
- Research Organization:
- Stanford Univ., CA
- OSTI ID:
- 5342306
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 9:2; Conference: 26. annual meeting of the Southeastern Section of the National Association of Geology Teachers, Winston-Salem, NC, USA, 23 Mar 1977
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANALCIME
STABILITY
LAUMONTITE
WAIRAKITE
ZEOLITES
CARBON DIOXIDE
DECOMPOSITION
PRESSURE DEPENDENCE
ROCK-FLUID INTERACTIONS
SODIUM CHLORIDES
SOLUTIONS
TEMPERATURE DEPENDENCE
ALKALI METAL COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MINERALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
SODIUM COMPOUNDS
152003* - Geothermal Data & Theory- Rock-Water-Gas Interactions