A bench-like feature running along a valley side, roughly parallel with the valley walls. Bridgland and Westaway (2007) Geomorph. argue that uplift is essential for the formation of river terraces; ‘their cyclic formation, however, almost invariably seems to have been a response to climatic fluctuation’. Bridgland (2002) Quat. Sci. Revs 19, 13 suggests a six-stage model:

1. 1. the incision phase in which terrace generation occurs, occurring at the transition to interglacial conditions (discharge is high as a result of melting permafrost);

2. 2. an aggradation phase, again at the glacial–interglacial transition, seen mainly in the lower reaches of valleys;

3. 3. the interglacial phase, in which fine-grained sedimentation (rarely preserved) is predominant;

4. 4. a further phase of incision at the interglacial–glacial transition;

5. 5. the main aggradational phase, at the interglacial–glacial transition, as a result of considerable sediment being liberated by the decline of vegetation;

6. 6. a phase of glacial climate during which there is relatively little activity, much of the potential discharge being locked up in permafrost.