Permafrost table at shallow depths in peat
The smooth surface in which the 25 cm-long knife is sticking is frozen peat representing the permafrost table. This frozen surface is only about 40 cm below the daylight surface of this relatively well-drained peat area. The peat is an excellent insulator, so heat, even during this exceptionally warm summer (Shilts, 1974) only penetrates to shallow depths beneath the highly organic surficial material. The shallow permafrost table, in concert with the lack of plasticity of the peat, leads to extensive development of frost cracks and frost polygons on this type of terrain, and little or no development of mudboils.
Updated 04/06/2010 AW