Suffosion is one of the twogeological processes by whichsubsidencesinkholes or dolines are formed, the other being due to collapse of an underlyingcave or void,[1] with most sinkholes formed by the suffosion process.[2][1] Suffosion sinkholes are normally associated withkarst topography although they may form in other types of rock includingchalk,gypsum andbasalt. In the karst of the UK'sYorkshire Dales, numerous surface depressions known locally as "shakeholes" are the result ofglacial till washing into fissures in the underlying limestone.[citation needed]
Suffosion occurs when loose soil,loess, or other non-cohesive material lies on top of a limestonesubstratum containing fissures and joints. Rain and surface water gradually wash this material through these fissures and into caves beneath.[2] Over time, this creates a depression on the landscape of varying depth.
Suffosion is a destructive process that creates instability leading to collapse of the soil structure, characterized by both mass loss and volumetric contraction. In suffosion, coarser particles lose their point-to-point contact. This is in contrast to suffusion, which is non-destructive and is characterized by mass loss without change in volume. In suffusion, coarser particles remain in point-to-point contact and fine particles are removed through the voids between them.[2][3]
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