Temporal changes in rock properties due to weathering during 350 ka were examined using sandstone gravel in fluvial terrace deposits with a known emergence time which were distributed in the Miyazaki Plain, South Kyushu.
The physical and mechanical properties and the colour index of b*-value change during the 0-to 120-ka period. The patterns of temporal changes in these rock properties are similar. The colour index of a*-value and pore radius change during 250-to 350-ka period. These results show that connected pores and content of hematite increase during 250-to 350-ka period. The specific surface area and the chemical weathering indices change at constant rates during 350 ka. This pattern suggests that chemical reactions occurred actively at the surface of the minerals with a large specific surface area. Since the specific surface area of sandstone increases at a constant rate during 350 ka, the chemical weathering indices change at a constant rate during 350 ka.