Chemical diffusion of fluorine in jadeite melt at high pressure
Chemical diffusion of fluorine in jadeite melt at high pressure
复制标题
高压下氟在硬玉熔体中的化学扩散
DOI：
10.1016/0016-7037(84)90302-8
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发表时间：
1984
影响因子：
5
通讯作者：
C. Scarfe
中科院分区：
文献类型：
--
作者：
Donald Bruce Dingwell;C. Scarfe
用硬玉熔体和含氟硬玉熔体（6.3wt%）的扩散偶，在10 ~ 15 kbar和1200 ~ 1400°C下研究了硬玉熔体中氟的化学扩散F）。扩散曲线数据表明，扩散过程是浓度无关的、二元的、F-O互扩散。F-O互扩散系数为1.3 × 10− 7 ~ 7.1 × 10− 7 cm 2/sec，远大于Kushiro（1983）对硬玉熔体中Si-Ge和Al-Ga互扩散的结果。的Arrhenius扩散活化能是在36至39千卡/摩尔的范围内相比，19千卡/摩尔的氟示踪剂在石灰铝硅酸盐熔体中的扩散。F-O互扩散的扩散系数和激活能随压力变化不大，但F-O、Al-Ga和Si-Ge互扩散的压力依赖性可能与每对互扩散物种的相对体积有关。氟的化学扩散系数的大小与黑曜石熔体中水的化学扩散系数相当。通过向硅酸盐熔体中添加氟或水，各种阳离子的扩散率显着增加。这一事实，再加上氟的高扩散性，表明F−离子是干燥铝硅酸盐熔体中的主要扩散物质，溶解的氟将加速干燥火成岩熔体中的化学平衡。
The chemical diffusion of fluorine in jadeite melt has been investigated from 10 to 15 kbars and 1200 to 1400°C using diffusion couples of Jadeite melt and fluorine-bearing jadeite melt (6.3 wt.% F). The diffusion profile data indicate that the diffusion process is concentration-independent, binary, F-O interdiffusion. The F-O interdiffusion coefficient ranges from 1.3 × 10−7to 7.1 × 10−7cm2/sec and is much larger than those obtained by Kushiro (1983) for Si-Ge and Al-Ga interdimision in jadeitic melts. The Arrhenius activation energy of diffusion is in the range of 36 to 39 kcal/mole as compared with 19 kcal/mole for fluorine tracer diffusion in a lime-aluminosilicate melt. The diffusivity and activation energy of F-O interdiffusion vary slightly with pressure, but the pressure dependence of F-O, Al-Ga and Si-Ge interdiffusion may be related to the relative volumes of the interdiffusing species for each pair. The magnitude of chemical diffusivity of fluorine is comparable to that of the chemical diffusivity of water in obsidian melts. The diffusivities of various cations are significantly increased by the addition of fluorine or water to a silicate melt. This fact, combined with the high diffusivity of fluorine, suggests that the F−ion is the principal diffusing species in dry aluminosilicate melts and that dissolved fluorine will accelerate chemical equilibration in dry igneous melts.