石槌山近傍の第三紀火成岩類に就いて（豫報）

On the Tertiary Igneous Rocks in the Vicinity of Ishizuchi-yama, Shikoku (Preliminary Report)

Yoshida Hironao

廣島大學地學研究報告

Geological report of the Hiroshima University

1. The stratigraphical succession of rocks in the Ishizuchi-Yama region may be tabulated as follows．
[Original table is skipped. For more details, please refer to the full text.]
2. The volcanic activity of this region occurred synchronous with the sedimentation of Shibukusa-formation(Miocene).
3. Omogo intrusive mass was intruded after the effusion of biotite-augite-bearing hypersthene-andesite.
4. Omogo intrusive mass consists of fine-grained two mica-granite, biotite-augite-bearing hypersthene-porphyrite, augite-bearing biotite-hypersthene-diorite-porphyrite and augite-bearing biotite-hornbiende-hypersthene-granodiorite.
5. The gradual transition of biotite-augite-bearing hypersthene-porphyrite into augite-bearing biotite-hornblende-hypersthene-granodiorite is interpreted as the result of slow cooling and contamination．
6.Fine-grained two mica-granite is a residual product of biotite-augite-bearing hypersthene-porphyrite magma.
7. The heterogeneous appearance of biotite-augite-bearing hypersthene-porphyrite dues to crashed and elongated xenoliths．

jpn

廣島大學理學部地學教室

[ISSN] 0073-2303

[NCID] AN00213676