Influence of dislocations on water leakage from fluid inclusions in quartz: a quantitative reappraisal
Influence of dislocations on water leakage from fluid inclusions in quartz: a quantitative reappraisal
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位错对石英流体包裹体漏水的影响：定量重新评估
DOI：
10.1127/ejm/6/6/0745
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发表时间：
1994
影响因子：
2.1
通讯作者：
C. Ramboz
中科院分区：
文献类型：
--
作者：
P. Cordier;J. Doukhan;C. Ramboz
石英中均匀流体包裹体的H2O选择性渗漏是变质岩中纯CO2包裹体形成的可能机制。由于水是可溶的并且在石英晶格中扩散，因此可能发生这种泄漏。位错是水点缺陷的优先位置和优先扩散路径。大密度的位错可能会增加水的渗漏。已经提出了几种模型来解释自然系统中的水泄漏。本文从定量的角度重新评价它们。我们表明，通过移动的位错清除流体包裹体中的水需要巨大的变形量。管道扩散沿着位错不会显著增强水渗漏动力学。在正常变质条件下，水的溶解度太低，不能解释寄主基质再水化导致的水渗漏;然而，其扩散率足够高，可以允许流体包裹体与环境之间的交换。这是天然岩石中流体包裹体最有可能发生水渗漏的过程。
Selective leakage of H2O from homogeneous fluid inclusions in quartz has been proposed as a possible mechanism for the formation of pure CO2 inclusions in metamorphic rocks. Such a leakage can occur because water is soluble and diffuses in the quartz lattice. Dislocations are preferential sites for the water point defects and preferential diffusion paths. A large density of dislocations is likely to enhance water leakage. Several models have been proposed to interpret this water leakage in natural systems. They are reappraised in the present paper from a quantitative point of view. We show that sweeping out water of fluid inclusions through mobile dislocations would require a tremendous amount of deformation. Pipe diffusion along dislocations does not significantly en hance the kinetics of water leakage. Under normal metamorphic conditions the solubility of water is too low to account for water leakage by re-hydration of the host matrix; however, its diffusivity is high enough to allow exchanges between fluid inclusions and the environment. This is the most likely process for water leakage from fluid inclusions in natural rocks.