A canyon or gorge is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic timescales. The processes of weathering and erosion will form canyons when the river’s headwaters and estuary are at significantly different elevations, particularly through regions where softer rock layers are intermingled with harder layers more resistant to weathering. Stream creek brook valley rivulet gully crack crevice fissure deep narrow valley continent erosion rock wall chasm cliff vertical steep. 4K UHD 3840×2160.