構造岩石学的にみた北部九州の変成岩類について
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概要
- 論文の詳細を見る
The metamorphic rocks of Northern Kyushu have been called the Sangun metamorphic rocks. Though they are composed generally of the crystalline schists of lower grades, they comprise the metamorphic rocks of higher grades, which have been considered to relate to the thermal effect of the intrusion of later granites. However, there remain a question whether the parts of higher grades represent the contact metamorphic type or the regional metamorphic type. On the view point of petrofabrics, the writer has distinguished between the two contact and regional types and set aside the effect of the contact metamorphism of the granites from the investigation of the metamorphic features related to the phase of the Akiyoshi Orogeny. The metamorphic rocks of the region have been divided into two groups, the northern and the southern group, and the boundary between them coincides with the so-called Matsuyama-Imari Tectonic Line, based on the followings: 1. The northern group has the tendency to be B∧B'-tectonites, while southern one to be simple B-tectonites. 2. The former is the high temperature-low pressure type, while the latter the low tempera ture-high pressure type. 3. The former was intruded by the Itoshima granite, the oldest granite of Northern Kyushu, while in the region of the latter, no granites are found correlative with the Itoshima granite. The writer proposes to name the metamorphic rocks of the northern region the Sangun metamorphic rocks proper, and those of the southern region the Chikugo metamorphic rocks. The former resembles the metamorphic rocks of Central Abukuma, and the latter the Sambagawa metamorphic rocks, on the view point of metamorphic features, but much remains unclarifled about their natures of stratigraphy and structure.
- 地学団体研究会の論文
- 1965-07-30