An Arctic Equivalent of the Grumusol

Describes soils near Umiat, Alaska: the gilgai micro- microrelief, sparse vegetation, and the desiccation cracks of considerable depth and width underlying a surface mulch of mineral soil aggregates. At depth, the soils grade into a thick structureless viscous clay which overlies permafrost. The formation of this soil involves processes which operate where soil materials are high in expanding lattice clays of the montmorillonite group. Freezing and evaporation cause desiccation. Thus the genesis of this arctic soil is almost identical with that of grumosols of temperate and warm climates. Soil profiles and tabulated chemical and physical data are included.