Meso and microstructures of non-active crush zone in granite at the Monju site

Shimada, Koji   ; Sueoka, Shigeru   ; Terusawa, Shuji

Examples of meso- and microstructures of non-active minor crush zones are useful to an activity evaluation of minor crush zone. We show meso- and microstructures from minor crush zones in granite located near the prototype of fast breeder reactor Monju. A 1-cm-thick cataclasite zone exhibiting weakly localized strain was observed. Dynamic recrystallization of quartz is not observed. Biotite in the zone is typically stretched and defining foliation of the cataclasite. The coexistence of the intracrystalline plastic deformation of biotite and the crushing of other granular minerals in the foliated cataclasite indicates that the most recent slip is the semi-brittle flow. The deformation microstructure of biotite indicates that the deformation condition of the latest slip is high-temperature and the minor crush zone is non-active fault.