Characteristics and formation processes of water-conducting fractures in the Hyuga Group of the Shimanto Belt

Ono, Takuya ; Yoshida, Hidekazu*

Very few studies have been performed to reveal characteristics and evolutions of water-conducting fractures in sedimentary rocks of accretionary complexes. Accretionary complexes can be a proposed site for geological disposal in Japan. Because of such backgrounds, we investigated fractures in borehole cores excavated from the Hyuga Group of the Shimanto Belt in the south of the Kyushu Island. Microscopic observation, SEM observation, XRD analysis and XRF analysis of minerals in/around fractures revealed characteristics of water-conducting fractures in accretionary complex and a process of fracture sealing according to carbonate mineral precipitation.