D42-18 カナダ東部、Abitibi greenstone belt の火山岩 : Late Archean におけるソレアイトとカルクアルカリ岩

概要

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In the Abitibi greenstone belt, Canada, volcanic rocks of∿2.7 Ga are distributed. They were metamorphosed to prehnite-pumpellyite to greenschist facies. Based on the bulk chemistry, they are classified into two series, high-Y and low-Y series, which roughly correspond to tholeiitic series and calc-alkaline series, respectively. There is no systematic difference in metamorphic grade between high-Y and low-Y series, suggesting the difference in original chemistry. Low-Y series dominates in upper stratigraphy. Concentrations of Al, K, Rb, Sr, Ba, Ni and LREE are higher in low-Y series, and Fe, Mn, and Ti are higher in high-Y series.
特定非営利活動法人日本火山学会の論文
1992-04-07