霊山およびその周辺の第三紀火岩類の化学成分 (予報)

抄録

Abstract: The basalts and andesites of the Ryozen formation (Miocene in age) of the northern Abukuma region, northeastern Japan are chemically analyzed. The aphyric basalts of the lower and upper parts of the formation are characterized by high Al₂O₃ content and their mineralogy and chemistry agree with that of the Kuno's high alumna basalt (Kuno, 1960). On the other hand, the olivine basalts of the middle part are relatively rich in MgO and poor in alkalies and TiO₂, thus bear the character of the tholeiitic basalts.