Density-driven deformation may occur when a sediment of higher bulk wet density is deposited on top of one of a lower bulk wet density, and occurs commonly in glacigenic sediments. By recognizing density-driven deformation of gravels and sands embedded in diamicts, it is possible to reconstruct relative preconsolidation states of the diamicts. Density-driven structures indicate that during deformation the diamict behaved as a viscous fluid, thus providing important evidence for the viscosity and physical state of diamicts after deposition, which has implications for the depositional environment. The density-driven process and its implications for reconstructing depositional environments is discussed. Criteria are given for the recognition of density-driven deformation stages of gravels and sands deposited on top of a viscous mud.