Suffosion

the leaching away or outflow of small mineral particles and dissolved substances by water filtering through a mass of rocks. Suffosion disrupts the microaggregate structure of the soil and causes the entire leached mass to settle, forming small and large enclosed depressions on the surface with diameters up to 10 m or, more rarely, 100–500 m. These depressions include minor depressions, conical depressions, sinkholes, and pits.