Other soil orders. Characterized by less strongly developed profiles. Accumulations of undecomposed organic material. Often very thick, with little or no mineral content. Specific type of clay that shrinks and swells a lot 2.
Cracks form when dry.
Particles fall into cracks. Get squeezed out when clay is wetted and cracks close. Causes churning, overturning of the soil profile. Therefore, no horizons develop. Fe, Mg rich lavas weather to base rich material.