Experimental studies on diffusion coefficients in pyroxenes.

扩散现象通常被观察到在焦苯矿物中。按顺序分析这种扩散现象的比率法的基础，因此，换算扩散数据是可以独立使用的。研究表明，焦氮素中的扩散协同效应的可靠实验数据， However，are minimal because of some experim\probelms including the sluggishness of the diffusion rates in？roxenes or the difficulty of synthesizing the active diffusion couples。In the present study the "001"解决方案Skaergaard Gabbro中的成年猪的Lamella被用作Diffusion Couples和复合概况通过分析来测量电子显微镜可以克服上面的问题。自然标本的组合概况在每个相位和变化中都很平坦。在不同运行期间，显著的差异剖面在1000 ° C和1200 ° C之间观察到该物种在50 ° C之间的温度升高。这些概况是由扩散模拟模型分析的，Tanzili和Heckel （1968年）开发的，在两相区域中发现了一个移动接口。而且我们终于可以在1000和1200之间的高温中获得Ca和（Mg、Fe）的可靠的干扰协同效应C.这些结果表明：（1）猪的干扰协同效应比成年人的强度大得多， （2）干扰率比ecer认为的要慢。（3）在阿伦尼乌斯图中，对金黄色和猪的扩散协同作用约为1100 ° C，可能对内部区域和外来区域的相互作用造成损害，以及（4）在金黄色和猪的扩散的激活能量约为120和88千卡/摩尔。相对高于1100 ° C，约22和18千卡/摩尔，相对低于1100 ° C。

Diffusion phenomena are commonly observed in pyroxene minerals. In order to analyze such diffusion phenomena on the basis of rate law, the cation diffusion data are indispensable. The reliable experimentl data of diffusion coefficients of cations in pyroxenes, however, are minimal because of some experimental probelms including the sluggishness of the diffusion rates in pyroxenes or the difficulty of synthesizing the active diffusion couples.In the present study the "001" exsolution lamella of pigeonite in augite from Skaergaard gabbro were used as diffusion couples and the compositional profiles were measured with an analytical electron microscope to overcome the above problems. The compositional profile of the natural specimen is almost flat within each phase and changes stepwise across the lamellar interface. However, significant diffusion profiles were observed on the specimens heated at temperatures of 50 c interval between 1000 and 1200 ゜C for different run durations. These profiles were then analyzed by the simulation model of diffusion, developed by Tanzili and Heckel (1968), which involves a moving interface in a two-phase region. And we could finally obtain the reliable interdiffusion coefficients of Ca and (Mg, Fe) in augite and pigeonite at temperatures between 1000 and 1200゜C.These results reveal that (1) the diffusion coefficient in pigeonite is a order of magnitude greater than that in augite, (2) diffusion rates are slower than ecer thought, (3) there are bendings at about 1100゜C in the Arrhenius plot of diffusion coefficients for both augite and pigeonite, probably due to the intersection of the intrinsic region and the extrinsic one, and (4) the activation energies of diffusion in augite and pigeonite are about 120 and 88kcal/mol, respectively above 1100゜C, and about 22 and 18 kcal/mol, respectively below 1100゜C.