Interdiffusion of NaSi—CaAl in peristerite
Interdiffusion of NaSi—CaAl in peristerite
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NaSi-CaAl在周长岩中的相互扩散
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
R. Yund
中科院分区：
文献类型：
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作者：
R. Yund
摘要“平均”互扩散系数(
$$ar D$$
)在An0到An26的时间间隔内，斜长石中NaSi-CaAl的交换是通过实验确定的peristerite exsolution薄片的均匀化时间来估计的。相邻（不同）薄片之间的平均间距为554±77 Å。在1100℃的空气中干燥加热98天，溶出组织没有变化；因此
$$ar D$$
（干）<10−17 cm2/s。这一限制与最近报告的“平均值”一致。
$$ar D$$
（干）值的胡滕洛赫区间（An70-90）在这个温度。在1.5 GPa下，加入约0.2重量％的水，从1100°C到900°C的“平均”扩散系数为：
$$ar D$$
（湿）=18−15+108(cm2/s) exp(−97±5 (kcal/mol)/RT)，其中R为气体常数，T为°K。这个
$$ar D$$
（湿）在1100°C时比
$$ar D$$
（干）为富钠和富钙斜长石。
AbstractThe ‘average’ interdiffusion coefficient (
$$ar D$$
) for NaSi—CaAl exchange in plagioclase for the interval from An0 to An26 was estimated from experimentally determined homogenization times for peristerite exsolution lamellae. The average spacing between adjacent (unlike) lamellae is 554±77 Å. Dry heating in air at 1,100°C for 98 days produced no change in the exsolution microstructure; thus
$$ar D$$
(dry)<10−17 cm2/s. This limit is consistent with the recently reported ‘average’
$$ar D$$
(dry) values for the Huttenlocher interval (An70–90) at this temperature. At 1.5 GPa with about 0.2 weight percent water added the ‘average’ diffusion coefficient from 1,100°C to 900°C is given by:
$$ar D$$
(wet)=18−15+108(cm2/s) exp (−97±5 (kcal/mol)/RT), where R is the gas constant, and T is °K. This
$$ar D$$
(wet) at 1,100°C is more than three orders of magnitude greater than
$$ar D$$
(dry) for Na- and Ca-rich plagioclases.