[O-08] Poster presentations by senior high school students

[O08-P48] Analysis of the geological structure in Fukano caldera, western Sendai

*Taishi Hiratuka¹, Karen Kobayashi¹, *Riku Kowada¹ (1.Miyagi prefecture sendai daisan high school)

Keywords:Fukano caldera, volcanic geology, western Sendai

The existence of paleo-caldera groups has been noted in the western part of Sendai City, Miyagi Prefecture, since around 2000. The distribution and formation process of these calderas are still unknown. Therefore, we investigated the strata constituting Fukano caldera, one of the calderas formed from the Late Miocene to Pliocene, to clarify the formation process of the caldera by analyzing the distribution of strata around Mt.Togami and the mineral composition of rocks. Based on the lithologic distribution of the rocks collected and analyzed, faults not described in previous studies were identified. Comparing the acquired data with previous studies, we inferred that the Mt.Togami body is intruded because it is composed of tuff, sandstone, and tuff-angular conglomerate, which show an almost horizontal attitude from the lower part of the mountain, and and andesite is distributed near the summit. The results of mineral combination analysis of the rock samples show a difference in mineral composition between the andesite in the horizontally deposited tuff and the andesite near the summit, suggesting that the igneous activity that formed the horizontal layers and the igneous activity that caused the penetration of the andesite were different.