The Influence of Crystal Growth Rate and Electrodiffusion (Sweeping) on Point Defects in &amp;amp;#945;-Quartz

Martin, J. J.; Halliburton, L. E.; Bossoli, R. B.; Armington, A.F.

doi:10.1109/freq.1982.200555

Cited by 5 publications

(1 citation statement)

References 8 publications

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“…As colorless layers in the analyzed profile contain more Al, Li, Na and Sb than smoky layers their lack in color centers are likely to be due to an excess of H + over (Li + +Na + ). The amount of trace elements incorporated into a quartz crystal mainly depends on its growth rate, the crystallization temperature, and the composition of the fluid (Martin et al 1982;Wilke and Bohm 1988). The fact that the Sn-and Ti-concentration along the analyzed profile follows a trend very different from that of Li, Na and Al demonstrates that several of these factors must have played a role.…”

Section: Tablementioning

confidence: 99%

Mobility and H 2 O loss from fluid inclusions in natural quartz crystals

Audétat¹,

Günther²

1999

Contributions to Mineralogy and Petrology

147

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Petrographic observations on quartz crystals from the Mole Granite (Australia) and other localities shed new light on the mechanisms of post-entrapment modification of fluid inclusions. These modifications include migration away from pseudosecondary trails, changes in fluid salinity and density, shape distortion and the formation of "sweat-haloes" around strongly deformed inclusions. Increases in fluid salinity, which usually are associated with inclusion migration, indicate water-losses of up to 50%. However, LA-ICP-MS-analysis of unmobilized and mobilized inclusions of the same trail reveals basically unchanged ratios of major-and trace element cations, with the exception of Li, which seems to be incorporated into the crystal lattice during migration. Despite the fact that all these modifications are closely related to deformation processes, they occur not only in mechanically deformed quartz, but also in free-standing crystals. In the latter samples, stress has been generated internally as a result of brazil-twinned growth and compositional zonation. These observations and their interpretation leads to a list of practical criteria that should help in differentiating between reliable and suspect fluid inclusions in other samples.

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Section: Tablementioning

confidence: 99%

Mobility and H 2 O loss from fluid inclusions in natural quartz crystals

Audétat¹,

Günther²

1999

Contributions to Mineralogy and Petrology

147

View full text Add to dashboard Cite

show abstract

Point defect chemistry of minerals under a hydrothermal environment

Hobbs¹

1984

J. Geophys. Res.

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The kinetics of rock/water interactions are sufficiently rapid that most hydrothermal systems in nature will be in equilibrium with the adjacent rock mass. The bulk rock chemistry buffers the fugacity of oxygen, which in turn fixes the fugacities of water and of hydrogen for a given pressure and temperature. Systems in which only water, oxygen, and hydrogen are present as fluid phases are considered here. Variations in the fugacity of oxygen by several orders of magnitude are possible locally, controlled by variations in local rock chemistry; these lead to relative small variations in the fugacity of water. Incorporation of a hydrogen defect that is capable of acting as an acceptor into silicates leads to a strong dependence of point defect chemistry upon the fugacities of both water and oxygen. The strong dependence on the fugacity of water is capable of explaining the hydrolytic weakening effect, but in view of the strong dependence on oxygen fugacity, the question should also be raised whether it is an oxygen effect that is observed in the classical hydrolytic weakening process or solely a dependence on changes in the fugacity of water. Examples are given for impure natural quartz, olivine, and albite with trace amounts of calcium.

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Probable Ion Signature in Quartz Electrodiffusion Data

Hanson

1984

38th Annual Symposium on Frequency Control

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The Influence of Crystal Growth Rate and Electrodiffusion (Sweeping) on Point Defects in &#945;-Quartz

Cited by 5 publications

References 8 publications

Mobility and H 2 O loss from fluid inclusions in natural quartz crystals

Mobility and H 2 O loss from fluid inclusions in natural quartz crystals

Point defect chemistry of minerals under a hydrothermal environment

Probable Ion Signature in Quartz Electrodiffusion Data

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