Proc Jpn Acad Ser B Phys Biol Sci. 2007 Feb;83(1):1-15. doi: 10.2183/pjab.83.1.
Studies of the origin of magmas in subduction zones, particularly in the Japanese island arc, have been significantly advanced by petrological, geochemical, geophysical and experimental studies during last 50 years. Kuno's original model(1)) for magma generation in the Japanese island arc, that tholeiite magmas are formed at relatively shallow levels in the mantle on the Pacific Ocean side whereas alkali basalt magmas are formed in deeper levels on the Japan Sea side, stimulated subsequent studies, particularly high-pressure experimental studies in which the author participated. Recent seismic tomographic studies of regions beneath the Japanese island arc demonstrate that seismic low-velocity zones where primary magmas are formed have finger-like shapes and rise obliquely from the Japan Sea side toward the Pacific Ocean side. Based on experimental studies, it is suggested that the compositions of primary magmas depend mainly on the H2O content and degree of melting in the melting zones, and that primary tholeiite magmas are formed by 10-25% melting of the source mantle containing less than 0.2 wt.% H2O. High-alumina basalt and alkali basalt magmas are formed by smaller degrees of melting of similar mantle, whereas primary boninite magmas are formed by more than 20% melting of the source mantle with more than 0.2 wt.% H2O, and finally, high-magnesia andesite magmas are formed by smaller degrees of melting of similar mantle.
在过去的 50 年中，通过岩石学、地球化学、地球物理学和实验研究，俯冲带（特别是日本岛弧）中岩浆起源的研究取得了显著进展。Kuno 最初的模型（1）认为，在太平洋一侧的地幔较浅处形成拉斑玄武质岩浆，而在日本海一侧的深部形成碱性玄武质岩浆，这一模型激发了随后的研究，特别是作者参与的高压实验研究。最近对日本岛弧下方区域的地震层析成像研究表明，原生岩浆形成的地震低速带呈指状，从日本海一侧向太平洋一侧倾斜上升。基于实验研究，表明原生岩浆的组成主要取决于熔融带中的 H2O 含量和熔融程度，并且含有小于 0.2wt.%H2O 的源地幔的 10-25%熔融形成原生拉斑玄武质岩浆。高铝玄武岩和碱性玄武质岩浆是由类似地幔的较小熔融程度形成的，而原始玻安岩质岩浆是由源地幔中 H2O 含量大于 0.2wt.%的 20%以上的熔融形成的，最后，高镁安山质岩浆是由类似地幔的较小熔融程度形成的。
