[M-IS11] ジオパーク

[MIS11-P01] Geoscientific Setting and Educational Significances of Iheya Island in the Ryukyu Arc, Eastern Asia

*尾方 隆幸¹、菅森 義晃²、小玉 芳敬² (1.琉球大学大学院理工学研究科、2.鳥取大学農学部)

キーワード：Ryukyu Arc、Chichibu Tectonic Belt、chert、sand、erosion、sedimentation

The Ryukyu Arc lies along the subduction zone between Eurasia and Philippine Sea Plates. Iheya Island is located in the central part of Ryukyu Arc, where geological setting connects the Chichibu Tectonic Belt. Sedimentary rocks are broadly exposed on island surface which form low altitude mountains and hills (maximum elevation is 294 m). Surface landforms significantly reflect different erosional processes of chert and sandstone. Present geomorphic processes produce remarkable sedimental landforms, such as a spit, bars and dunes, assisted by rapid longshore current and strong winter monsoon. Such stratigraphical, petrological and geomorphological features present significant sites to study seamless geoscience. Geoscientist should discuss scientific significances for conservation of several geosites in Iheya Island.