We examined the evolution of the magma feeding system at Zao volcano (NE Japan) during seven episodes of Komakusadaira pyroclastic activity (ca. 33–12.9 ka). The rocks, which are calc-alkaline and medium-K basaltic andesite to andesite (54.9–59.5% SiO₂), are herein suggested to have been derived from two main magmatic end-members: silicic andesite magma (59~60% SiO₂, 940~970°C, cpx-opx-plg as phenocrysts) and basaltic magma (52% SiO₂, ~ 1085°C, Fo_78~80 olv-plg as phenocrysts). These two end-members retained their compositional integrities throughout all seven eruptive episodes. The presence of Mg-rich (Fo_{> 80}) olivine phenocrysts suggests the basaltic end-member was derived from fairly primitive magma (> 1100°C), which differentiated during ascent. By examining temporal variations in the chemical compositions of the phenocrystic minerals, three evolutionary pathways that produced the erupted products are defined; these are reflected in seven sequential episodes: (1) Crystal-rich silicic andesite magma was repeatedly withdrawn from the reservoir by the forced injection of basaltic magma (episode 1). (2) Crystal-poorer intermediate magma was formed by effective mixing of injected basaltic magma. Subsequent eruption of the intermediate magma was triggered by a new injection of mafic magma. The percentage of intermediate magma involved in the eruptions decreased over time (episodes 2–4). (3) By repeated fairly primitive to basaltic magma injections, the percentage of the mobilized part of the silicic andesite magma involved in the erupted magma gradually increased over time (episodes 5–7).

我们考察了藏王火山（日本东北部）在7次Komakusadaira火山碎屑活动（约33–12.9 ka）期间岩浆供给系统的演化。岩石上，其是钙碱性和介质-K玄武安山岩到安山岩（54.9-59.5％的SiO ₂），在本文中建议已经从两个主要的岩浆端员衍生的：硅酸安山岩岩浆（59〜60％的SiO ₂，940〜970℃，CPX-OPX-PLG作为斑晶）和玄武岩浆（52％的SiO ₂，〜1085℃下，FO _78〜80 OLV-PLG作为斑晶）。在所有七个爆发事件中，这两个最终成员均保持其组成完整性。富含镁（Fo _{> 80}）橄榄石特征表明，玄武岩的端部成员来自相当原始的岩浆（> 1100°C），在上升过程中有所区别。通过检查微晶矿物化学成分的时间变化，可以确定产生喷发产物的三种进化途径。这些在七个连续的事件中得到反映：（1）通过强制注入玄武质岩浆反复从储层中抽出富含晶体的硅质安山岩岩浆（第1集）。（2）通过有效混合注入的玄武岩浆形成较差的中岩浆。岩浆岩的新注入触发了随后的中岩浆喷发。随着时间的推移，涉及喷发的中间岩浆的百分比下降（第2-4集）。（3）通过反复向玄武岩浆注入相当原始的东西，