Nohi Rhyolites - Nohi Rhyolites

Japanese: 濃飛流紋岩類 - のうひりゅうもんがんるい

Acidic volcanic rocks from the Late Cretaceous Period distributed from the Hida and Tono regions of Gifu Prefecture to the Kiso region of Nagano Prefecture. Formerly known as granite porphyry or quartz porphyry, they were renamed to their current names in the early 1960s when it was discovered that they consist mainly of welded tuff. They stretch for about 120 km from the northwest to the southeast, are over 2,000 m thick, and have a total volume of more than 10,000 ^km3 . They are accompanied in various places by hypabyssal rocks of the same origin, such as granite porphyry, and have been widely subjected to thermal metamorphism due to the intrusion of granite from the late Cretaceous Period.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

岐阜県飛驒，東濃地方から長野県木曾地方にかけて分布する白亜紀後期の酸性火山岩類。古くは花コウ質斑岩，石英斑岩などと呼ばれたが，1960年代初めに主として溶結凝灰岩からなることが明らかにされ，現在の名称に変わった。北西～南東方向に約120km連続し，厚さは2000m以上で，全容積は1万km³を超える。花コウ斑岩など同源の半深成岩類を各所に伴い，また白亜紀末の花コウ岩類の貫入により，広く熱変成作用を受けている。

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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