富山県布施川上流,黒部川下流域の片岩・片麻岩・花崗岩中のカリ長石の三斜度

概要

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Most K-feldspars of schists, gneisses and granites in the upper Fuse-gawa and lower Kurobe-gawa areas show broad or composite 131 and 131 peaks. One hundred and forty-four K-feldspars examined are divided into eight types on the basis of 131 and 131 reflections. In types IV-VIII with resolved 131 and 131 peaks Δ value is variable; it is distributed over a wide range (Δ=0.57-0.91) in type IV-V, but tends to become higher from type IV to VIII. 2 V_x value in a single grain is variable and its distribution pattern is also variable. These results reveal clearly that the inversion of monoclinic to triclinic K-feldspar is "randomly disordered" and of the second order. From the analysis of obliquity and optics of K-feldspar, monoclinic or nearly monoclinic K-feldspar in the schists, gneisses, augen gneisses and Iori granite has been transformed into more triclinic one by dislocation metamorphism with hydrothermal alteration, suggesting an upheaval movement at a deep place. The upheaval movement might have started from the stage of K-feldspathization and to have continued until a time after the intrusion of the Iori granite. However, the isotopic ages obtained from the Hida basement suggest that the upheaval ceased nearly immediately after the intrusion of the Iori granite. The Kitamata-dani granite intruded after the deep-seated upheaval movement.
日本地質学会の論文