illuviate

1. (geology) To leach from an overlying stratum and accumulate in suspension.Examples: "This is due to the reason that these materials are rich in organic matter which tend to illuviate from the surface to the subsurface in the longrun and have tend to increase the clay per cent in the subsurface soil layers (Prashanthi, 1997)."; "Defining the exact mechanism by which these metal cations become mobile and illuviate is where the two main theories of podzolization diverge."; "In flooding seasons, because the Eh value rises beginning from the lower part of this horizon downwards, some substances moving with the water begin to illuviate here, resulting in the formation of mottling spots and coatings."