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川西乡城地区的球颗状玻镁安山岩是一种玻璃质、含辉石斑晶、具淬火结构的中性熔岩．它相对富硅富镁、贫钛贫磷，产于三叠纪川西义敦岛弧早期火山活动阶段．外观最醒目特征是具有球颗构造，从化学成分和岩浆性质分析，球颗构造是成岩过程中岩浆不混溶的直接产物．不混溶对岩石成分和结构起着控制作用；岩石中球颗相富硅碱，以玻璃质结构为主，而基质相富铁镁，以微晶结构为主．成岩时化学成分随岩浆不混溶发生相对分离，该岩浆属于一种低程度不混溶．结构差异是两相中矿物结晶能力不同的结果
The globular magnesian andesite in the urban area of western Sichuan is a glassy, pyroxene-containing crystal with a neutral lava with a quenched structure. It is relatively rich silicon-rich magnesium, poor lean titanium, produced in the Triassic Sichuan Island West Island early volcanic stage. The most striking feature is the appearance of a spherical structure. From the analysis of chemical composition and magmatic properties, the spherical structure is the direct product of immiscibility of magma during diagenesis. The immiscibility plays a controlling role on the composition and structure of the rock. The spherical phase in the rock is rich in soda and alkali, mainly vitreous structure, and the matrix phase is rich in Fe and Mg, mainly taking the microcrystalline structure. The chemical composition of diagenetic rocks is relatively immiscible with magma, which belongs to a low degree of immiscibility. Structural differences are the result of the different crystallization capacities of the minerals in the two phases