The compositional ranges of Mn-pyroxenoids

利用EDS分析了日本锰辉石和单斜辉石。在CaSiO_3摩尔分数低于10%的情况下，只有贫钙的镁铁锰矿在较高温度下才稳定存在。在所研究的辉石岩中，FeSiO_3的摩尔含量变化范围很大，达到32mol%。蔷薇辉石在较宽的温度范围内是稳定的，其组成范围为CaSiO_3单一的10%~ 20%和（Fe）的30%以下。Mg）SiO_3摩尔比。低温条件下形成的蔷薇辉石为高钙蔷薇辉石，其CaSiO_3摩尔分数可达35%左右。钙硅镁石的组成范围很宽，CaSiO_3的摩尔分数在30%~ 55%之间，（Fe）的摩尔分数在20%以下。Mg）SiO_3摩尔比。在高温条件下，（Fe）含量低于20%时，在单斜辉石组成区稳定。Mg）SiO_3摩尔比。温度的降低促使钙锰硅石的出现，单斜辉石在Ca（Fe，Mg）Si_2O_6- CaMnSi_2O_6界面上的分布变得连续。也就是说，在较低的温度下，丁羟胺的稳定范围受到限制。但在单斜辉石区之外也能存在。

Mn-pyroxenoids and clinopyroxenes from Japan were analysed using EDS. Pyroxmangite is extant under 10 % of CaSiO_3 mole, and only Ca-poor one is stable at higher temperatures. The compositional range of FeSiO_3 mole varies widely and reaches 32 mole % among studied pyroxmangites. Rhodonite may be stable under the wide temperature range, and its compositional range exsists between 10 % and 20 % of CaSiO_3 sole and under 30 % of (Fe. Mg)SiO_3 mole. Rhodonite accompanying johannsenite formed under low temperature is high-calcian, and its CaSiO_3 mole reaches about 35 %. Bustamite has wide compositional range located within the area between 30 % and 55 % of CaSiO_3 mole and under 20 % of (Fe. Mg)SiO_3 mole. In case of high temperature, bustamite is stable in the compositional area of clinopyroxene under 20 % of (Fe. Mg)SiO_3 mole. The decreasing temperature invites the appearance of johannsenite near CaMnSi_2O_6, and the distribution of clinopyroxenes on Ca(Fe, Mg)Si_2O_6- CaMnSi_2O_6 join becomes consecutive. That is, the stability field of bustamite is limited at lower temperatures. but it is able to exist outside of clinopyroxene area.