Diorite (English spelling)

Japanese: セン緑岩(閃緑岩) - せんりょくがん（英語表記）diorite

A type of plutonic igneous rock. It is a plutonic rock equivalent to the volcanic andesite, and is a holocrystalline rock containing 55-60% silica (SiO _{2 )} , mainly plagioclase and amphibole, with small amounts of pyroxene, biotite, and quartz. Quartz-containing quartzite is sometimes produced in large quantities in granite areas, and in the granite batholith on the west coast of the Americas, the western quarter is occupied by quartzite, and as you move eastward, it always becomes felsic. The eastern edge of this quartzite distribution area is called the Quartzite Line. Quartzite is found in very small amounts in the batholith zone of East Asia, and the Quartzite Line does not exist here, showing a significant difference from the Americas.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

深成火成岩の一種。火山岩の安山岩に相当する深成岩で，シリカSiO₂55～60％，おもに斜長石と角セン石，少量の輝石，黒雲母，石英などを含む完晶質岩。花コウ岩地帯には石英を含む石英セン緑岩が多量に産出することがあり，南北アメリカ大陸西海岸の花コウ岩質バソリスではその西側1/4が石英セン緑岩で占められ，東方へいくにつれ，つねにフェルシックとなる。この石英セン緑岩分布域の東端は石英セン緑岩線と呼ばれる。石英セン緑岩は東アジアのバソリス帯ではごく少量で，ここでは石英セン緑岩線は存在せず，アメリカ大陸と著しい相違を示す。

出典　株式会社平凡社世界大百科事典第２版について　情報

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