Chemical composition of subsurface waters

White, Deborah; Hem, John David; Waring, G.S.

doi:10.3133/pp440f

Cited by 198 publications

(83 citation statements)

References 12 publications

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“…Typical analyses of ground waters from different rock types have been assembled by White, Hem, and Waring (1963); some of their data are summarized in Table 5. Ground waters from granitic rocks have magnesium and potassium contents that are both low and nearly equal.…”

Section: Phase Stability Diagrammentioning

confidence: 99%

Laboratory Alteration of Trioctahedral Micas

Hoda

1972

Clays and clay miner.

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Abstract-Artificial alteration of thirty-five trioctahedral .and one dioctahedral micas by solutions varying in strength from 0.001 to 1.00 molal magnesium sulfate was found to approximate a normal exchange reaction after surface effects are eliminated. The equilibrium constants for the reaction:range from 0.0001 to 0.0028 and average 0.0010 in value. X-ray diffraction study reveals that iron-rich micas tend to develop a 1 : 1 mixed-layer biotite-vermiculite structure in weak magnesium sulfate solutions whereas magnesium-rich biotite and phlogopite alter to vermiculite. Mica composition also influences the degree of alteration of mica to vermiculite. High fluorine and octahedral multivalent cation contents tend to retard the reaction whereas high magnesium content and perhaps high calcium contents tend to favor the alteration. The equilibrium constant data indicate that vermiculite and hydrobiotite are more stable than trioctahedral micas in most weathering environments.

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Section: Phase Stability Diagrammentioning

confidence: 99%

Laboratory Alteration of Trioctahedral Micas

Hoda

1972

Clays and clay miner.

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“…The average K + content of river water is 2.3 ppm (Livingston, 1963), with many ground waters a little higher (see White et al, 1963). These average K + levels are probably higher than the critical K + levels of most dioctahedral micas, hence the conclusion by RausellColom et al (1965) that muscovites will not exchange their K + in most natural waters.…”

Section: Cricical K + Levels and The K + Content Of Natural Watersmentioning

confidence: 73%

Mica-Derived Vermiculites as Unstable Intermediates

Kittrick

1973

Clays and clay miner.

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Abstract--Stability determinations were made by solubility methods on two trioctahedral mica-derived vermiculites. The phlogopite-'derived vermiculite was found to be unstable under acid solution conditions, where stabilities of montmorillonite, kaolinite and gibbsite had previously been determined. An attempt was next made to locate a possible montmorillonite-vermiculite-amorphous silica triple point. This triple point involved conditions of alkaline pH, high pH4SiO 4 and high Mg 2+. These are conditions where phlogopite and biotite-derived vermiculites are most likely to control equilibria/f they are stable minerals. The montmorillonite-vermiculite-amorphous silica samples went to the montmorillonite-magnesiteamorphous silica triple point, leaving no stability area whatsoever for the vermiculites. These large particle-size, trioctahedral, mica-derived vermiculites appear to be unstable under all conditions of room T and P.Arguments are presented indicating that micas are unstable in almost all weathering environments. A hypothesis is proposed that mica-derived vermiculites result from the unique way in which unstable micas degrade in these environments. It is proposed that vermiculite derives from a series of reactions whose relative rates often result in an abundance of vermiculite. These relative reaction rates are slow for mica dissolution, rapid for K removal and other reactions pursuant to vermiculite formation, and slow for vermiculite dissolution. In chemical terms, mica-derived vermiculites may be considered fast-forming unstable intermediates.

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“…Rare albite coincidentally replaced some plagioclase feldspars, but was itself not sericitized. At 225°C, contemporaneous formation of sericite and albite requires a Na/K ratio between 15 and 50 (Figure 24), well within the range of thermal waters associated with epithermal mineralization (White et al, 1963). The alteration of plagioclase in the presence of albite requires the addition of potassium and hydrogen and the removal of calcium, according to the reaction:…”

Section: Analyses Listed Inmentioning

confidence: 99%

Alteration and vein mineralization, Schwartzwalder uranium deposit, Front Range, Colorado

Wallace¹

1983

Open-File Report

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The Schwartzwalder uranium deposit, in the Front Range west of Denver, Colorado, is the largest vein-type uranium deposit in the United States. The deposit is situated in a steeply dipping fault system that cuts Proterozoic metamorphic rocks. The host rocks represent a submarine volcanic system with associated chert and iron-and sulfide-rich pelitic rocks. Where faulted, the more competent garnetiferous and quartzitic units behaved brittlely and created a deep, narrow conduit.The ores formed 70-72 m.y. ago beneath 3 km of Phanerozoic sedimentary rocks. Mineralization included two episodes of alteration and three stages of vein mineralization. Early carbonatesericite alteration pseudomorphically replaced mafic minerals, whereas the ensuing hematite-adularia episode replaced only the earlier alteration assemblage. Early vein mineralization produced a minor sulfide-adularia-carbonate assemblage. Later vein mineralization generated the uranium ores in two successive stages. Carbonates, sulfides, and adularia filled the remaining voids. Clastic dikes composed of fault gouge and, locally, ore were injected into new and existing fractures.Geologic and chemical evidence suggest that virtually all components of the deposit were derived from major hornblende gneiss units and related rocks. The initial fluids were evolved connate/metamorphic water that infiltrated and resided along the extensive fault zones. Complex fault movements in the frontal zone of the eastern Front Range caused the fluids to migrate to the most permeable segments of the fault zones. Heat was supplied by increased crustal heat flow related to igneous activity in the nearby Colorado mineral belt. Temperatures decreased from 225°C to 125°C during later mineralization, and the pressure episodically dropped from 1000 bars. The CO^ fugacity was initially near 100 bars, and uranium was carried as a dicarbonate complex. Sudden decreases in confining pressure during fault movement caused evolution of 009 and a consequent increase in pH. Uranium was released with destruction of the uranyl complexes; it was subsequently reduced by aqueous sulfur species, thereby leading to the precipitation of pitchblende. ACKNOWLEDGMENTS

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Chemical composition of subsurface waters

Cited by 198 publications

References 12 publications

Laboratory Alteration of Trioctahedral Micas

Laboratory Alteration of Trioctahedral Micas

Mica-Derived Vermiculites as Unstable Intermediates

Alteration and vein mineralization, Schwartzwalder uranium deposit, Front Range, Colorado

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