Weathering rind thickness of stones was measured on a crescentic ridge and on its surrounding low ridges and slopes in Yabusawa cirque (35° 43' N, 138° 11' E, 2, 885 m a.s.l.; est. MAAT-2.3°C) in the Akaishi Mountains, central Japan. Although a numerical time scale has not been established, the crescentic ridge, which is most likely of rock glacier origin, is considered to be the oldest at the study site from weathering rind data. Meanwhile, the debrismantled valley floor is estimated to be younger in the late Holocene. This fact suggests that more recent movement of rock glacier is proposed for the occurrence on landforms of the debrismantled valley floor.
