Thaw depth Thaw depth In soil science, the thaw depth or thaw line is the instantaneous level down to which the soil has warmed to zero degrees celcius. The active layer thickness is the maximum thaw depth over a period of two years. The layer of soil over the thaw depth is called the active layer, while the soil below is called permafrost. The term frost front refers to the varying position of the thaw line during the periods of freezing/thawing. The knowledge of the thaw depth is important for the two major reasons: its influence on the ecology and on construction
Soil in the evolution of a soil. They are: parent material, climate, topography (relief), organisms, and time. When reordered to climate, relief, organisms, parent material, and time, they form the acronym CROPT. The mineral material from which a soil forms is called parent material. Rock, whether its origin is igneous, sedimentary, or metamorphic, is the source of all soil mineral materials and the origin of all plant nutrients with the exceptions of nitrogen, hydrogen and carbon. As the parent material is chemically and physically weathered, transported, deposited and precipitated, it is transformed into a soil. Typical soil parent mineral materials are: