Suffosion is the mechanical relocation of fine particles by pore water.
Fine grains are transported underground through the existing pore area, while
the matrix of the bigger particles remains untouched.
This kind of processes happen in karst but is not restricted to soluble rocks.
It is also common in soils and soft sandstones.
In this case it is called suffosional pseudokarst, as it is the
development of caves and dolines as a purely mechanical process.
Pseudokarst features have the appearance of karst landforms but are formed by
processes other than bedrock dissolution.
It is possible in all granular aquifers, in other terms in porous rocks where
the groundwater flows slowly through the pores of the rock.