不平衡条件下单斜辉石形成的一些探讨

辉石作为一种主要造岩矿物广泛出现于许多岩类中,在基性火成岩中它更占有重要的地位。平衡条件下辉石的产出条件及其有关的相平衡关系,前人已有大量实验研究。

A DISCUSSION ABOUT THE CONDITIONS FOR THE SYNTHESIS OF CLINOPYROXENES IN THE NONEQUILIBRIUM

In the synthesis of pyroxenes and plagioclases, the phase relations, concerning the temperature conditions and the chemical compositions, have been studied through two different heat passages at atmospheric pressure. Optimum temperature for the greatest growth power of synthetic clinopyroxenes is at about 900℃ in the basaltic system under the nonequilibrium. In general, the plagioclase appeares easily at temperature about 1000° to 1100℃. The chemical composition may be an important agent in the synthesis of clinopyroxenes. On the basis of the results of these experiments in various conditions of nonequilibrium, The authors identify an optimum compositional region for the synsthesis of clinopyroxenes in absence of plagioclase, and consequently remove the Bowen’s eutectic curve in the equilibrium diagram for Di-An-Ab to the side of the plagioclase; at temperature between 900° and 1000℃.It seems that pyroxenes containing more content of Tachermark’s molecule or jadeite molecule may be synthesized at 1 atm. in the nonequilibrium condition, therefore, the high pressure condition for synthesizing pyroxenes with more Al2O3 is an uncertainty.