Magma generation processes by crustal melting at subduction zone with continental crust

为了弄清地壳熔融产生的岩浆数量、成分和生成时间尺度，了解大陆边缘岩浆活动的多样性，我们在热岩浆反复注入地壳熔融产生岩浆的物理模型基础上，进行了地壳熔融作用下的岩浆成因数值实验。数值实验结果表明：(1)地壳初始温度和热岩浆的注入速率控制着地壳熔体的总量；(2)地壳熔体的组成主要受初始地壳温度和热岩浆的注入厚度的影响；(3)大于1km~3的岩浆的生成时间尺度为数万年。这些结果与自然火成岩活动的特征相一致。

We carried out numerical experiments of magma genesis by crustal melting on the basis of physical model where hot magmas injecting into crust repeatedly melt the crust and produce magmas, in order to clarify amount, composition, and generation timescale of magma produced by crustal melting and understand variety of igneous activities in continental margin. The results of the numerical experiments indicate that (1) the initial crustal temperature and injection rate of the hot magmas govern total amount of crustal melt, (2) composition of crustal melt is dominantly affected by the initial crustal temperature and injection thickness of the hot magma, and (3) generation timescale for magmas with more than 1 km3 volume is several ten thousands years. These results are consistent with features of natural igneous activity.