[M-IS08] Geopark

[MIS08-P05] Geological Issues of the Shimanto Belt in the Ryukyu Arc: For Advanced Geoscientific Stories and Tours in “Yambaru”, Okinawa

*Koki Kawamura¹, Takayuki Ogata² (1.Geo Star Guide, 2.Graduate School of Engineering and Science, University of the Ryukyus)

Keywords:Ryukyu Arc, geological structure, accretionary complex, Shimanto Belt, Nago Formation, Kayo Formation

The Shimanto Belt consists of the northern belt (Cretaceous stratigraphy) and the southern belt (Paleogene stratigraphy). In the Ryukyu Arc, the Nago and Kayo Formations are identified within the Shimanto Belt, which produce significant sites for geological excursions and tours. The authors focused on geological issues of the Shimanto Belt during the geoscientific tours. On January 28, 2024, the authors explained petrological features of the Nago and Kayo Formations. On February 12, 2024, the authors elaborated that each formation correlates independently as the sub-structure in the Shimanto Belt based on geological structure and zonation formed by accretionary complex. The most difficult problem arises from the scarcity of paleontological data in the Nago Formation that generally lacks fossils due to metamorphism. Such an uncertain situation contributes to advanced academic field excursions, not only for scientists but also for geoscientific guides and participants. Future geoscientific tours should aim to adjust the explanations to interests and knowledge of participants based on scientific data and discussion.