Chapter 6: Cryosolic Order

A diagrammatic representation of profiles of some subgroups of the Cryosolic order is shown in Figures 30 and 31. Individual subgroups may include soils that have horizon sequences different from those shown. In the description of each subgroup, presented later in this chapter, a common horizon sequence is given; diagnostic horizons are underlined and some other commonly occurring horizons are listed.

Figure 30 Diagrammatic horizon pattern of some subgroups of the Cryosolic order

Figure 30 is a diagrammatic horizon pattern of some subgroups of the Cryosolic order. Orthic Eutric Static Cryosol (OE.SC) Common horizon sequence: Om, LFH, Bm, BCgj, Cz. These Static Cryosols have a relatively high degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bm horizon less than 10 cm thick. 2. They have a pH (0.01 M CaCl2) of 5.5 or greater in some or all of the B horizons. 3. The surface horizons are not strongly gleyed, but gley features commonly occur immediately above the permafrost table. Orthic Dystric Static Cryosol (OD.SC) Common horizon sequence: Om, LFH, Bm, BCgj, Cz. These acidic Static Cryosols have a low degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bm horizon less than 10 cm thick. 2. They have a pH (0.01 M CaCl2) of less than 5.5 throughout the B horizons. 3. The surface horizons are not strongly gleyed, but gley features commonly occur immediately above the permafrost table. Brunisolic Eutric Static Cryosol (BRE.SC) Common horizon sequence: LFH, Bm, BCgj, Cz. These Static Cryosols have a relatively high degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bm horizon at least 10 cm thick. 2. They have a pH (0.01 M CaCl2) of 5.5 or greater in some or all of the B horizons. Brunisolic Dystric Static Cryosol (BRD.SC) Common horizon sequence: LFH, Bm, BCgj, Cz. These acidic Static Cryosols have a low degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bm horizon at least 10 cm thick. 2. They have a pH (0.01 M CaCl2) of less than 5.5 throughout the B horizons. Regosolic Static Cryosol (R.SC) Common horizon sequence: C, Cg, Cz. These Static Cryosols have developed on recently deposited or strongly cryoturbated soil materials. They are identified by the following properties: 1. These soils lack B horizons. 2. These soils may have thin (<15 cm thick) peaty organic layers and a thin Ah horizon. Gleysolic Static Cryosol (GL.SC) Common horizon sequence: Om, Bg or Cg (or both), Cz. These Static Cryosols have developed in poorly drained areas under reducing conditions. The name Gleysolic, rather than Gleyed, is used because these soils are not equivalent in degree of gleying to Gleyed subgroups of other orders. Gleysolic subgroups of Cryosolic soils have evidence of gleying similar in degree to that of soils of the Gleysolic order. They are identified by the following properties: 1. These soils have evidence of gleying in the form of low chromas or mottling to the mineral surface. 2. Their surface mineral horizon, Bg or Cg,may be overlain by organic layers less than 40 cm thick. Glacic Organic Cryosol (GC.OC) Common horizon sequence: Of, Om or Oh, Wz. These Organic Cryosols are identified by the following properties: 1. They have a layer of ground ice greater than 30 cm thick with an upper boundary within 1 m of the surface. 2. The ice layer contains more than 95% ice by volume. Terric Mesic Organic Cryosol (TME.OC) Common horizon sequence: Om, Omz, Cz. These Organic Cryosols are identified by the following properties: 1. They have a mineral contact within 1 m of the surface, or the mineral layer is greater than 30 cm thick with an upper boundary within 1 m of the surface. 2. They are composed dominantly of mesic material above the mineral contact. Fibric Organic Cryosol (FI.OC) Common horizon sequence: Of or Om, Of, Ofz. These Organic Cryosols are identified by the following properties: 1. They have organic layers thicker than 1 m. 2. They are composed dominantly of fibric material in the control section below a depth of 40 cm. .


Figure 31 Schematic representation of horizon pattern in some Turbic subgroups of the Cryosolic Order

Figure 31 is a Schematic representation of horizon pattern in some Turbic subgroups of the Cryosolic Order. Orthic Eutric Turbic Cryosol (OE.TC) Common horizon sequence: Om, Bmy, BCy, Cgy, Omy, Cz. These Turbic Cryosols have a relatively high degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bmy horizon and may have a Bm horizon less than 10 cm thick. 2. The horizons are strongly disrupted by cryoturbation. Tongues of mineral and organic horizons, organic and mineral intrusions, and oriented stones commonly occur. 3. These soils have a pH (0.01 M CaCl2) of 5.5 or greater in some or all of the B horizons. 4. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table. Orthic Eutric Turbic Cryosols have a Bmy horizon and subsurface organic (Omy, Ohy) or organic-rich, mineral horizons (Ahy). Surface organic horizons up to 15 cm thick, moder Ah horizons, and Bm horizons less than 10 cm thick may occur. Brunisolic Eutric Turbic Cryosol (BRE.TC) Common horizon sequence: Om, Bm, Bmy or BCy, Cgy, Omy, Cz. These Turbic Cryosols have a relatively high degree of base saturation, as indicated by their pH. They are identified by the following properties: 1. These soils have a Bm horizon, at least 10 cm thick, which is continuous over the imperfectly to well-drained part of the pedon that is relatively unaffected by cryoturbation. 2. The horizons, other than the Bm, are strongly disrupted by cryoturbation. Tongues of mineral and organic horizons, organic and mineral intrusions, and oriented stones commonly occur. 3. These soils have a pH (0.01 M CaCl2) of 5.5 or greater in some or all of the B horizons. 4. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table. Regosolic Turbic Cryosol (R.TC) Common horizon sequence: Om, Cy, Cgy, Cz. These Turbic Cryosols have developed on recently deposited or strongly cryoturbated soil materials. They are identified by the following properties: 1. These soils lack B horizons. 2. These soils usually have little incorporated organic matter. 3. Cryoturbation is manifested by oriented stones, displacement of materials, and sorting. Gleysolic Turbic Cryosol (GL.TC) Common horizon sequence: Om, Bgy or Cgy (or both), Cz. These Turbic Cryosols have developed in poorly drained areas under reducing conditions. The name Gleysolic, rather than Gleyed, is used because these soils are not equivalent in degree of gleying to Gleyed subgroups of other orders. Gleysolic subgroups of Cryosolic soils have evidence of gleying similar in degree to that of soils of the Gleysolic order. They are identified by the following properties: 1. They have evidence of gleying in the form of low chromas or mottling to the mineral surface. 2. Their uppermost mineral horizon, Bgy or Cgy, may be overlain by organic layers less than 40 cm thick, or a combination of surface and subsurface organic horizons >15 cm thick .

Soils of the Cryosolic order occupy much of the northern third of Canada where permafrost exists close to the surface of both mineral and organic deposits. Cryosolic soils predominate north of the tree line, are common in the subarctic forest area in fine-textured soils, and extend into the boreal forest in some organic materials and into some alpine areas of mountainous regions. Cryoturbation of these soils is common and may be indicated by patterned ground features such as sorted and nonsorted nets, circles, polygons, stripes, and earth hummocks.

Cryosolic soils are formed in either mineral or organic materials that have permafrost either within 1 m of the surface or within 2 m if the pedon has been strongly cryoturbated laterally within the active layer, as indicated by disrupted, mixed, or broken horizons. They have a mean annual temperature ≤0°C. Differentiation of Cryosolic soils from soils of other orders involves either determining or estimating the depth to permafrost.

The Cryosolic order is divided into three great groups: Turbic Cryosol, Static Cryosol, and Organic Cryosol based on the degree of cryoturbation and the nature of soil material, mineral or organic, as indicated in the Cryosolic order chart.

Cryosolic Order
  Turbic Cryosol Static Cryosol Organic Cryosol
Diagnostic horizons are underlined
Soil mineral mineral organic
Cryoturbation marked, usually patterned ground none none
Permafrost within 2m of surface within 1m of surface within 1m of surface


Great Group Subgroup
Turbic Cryosol Orthic Eutric Turbic Cryosol OE.TC
Orthic Dystric Turbic Cryosol OD.TC
Brunisolic Eutric Turbic Cryosol BRE.TC
Brunisolic Dystric Turbic Cryosol BRD.TC
Gleysolic Turbic Cryosol GL.TC
Regosolic Turbic Cryosol R.TC
Histic Eutric Turbic Cryosol HE.TC
Histic Dystric Turbic Cryosol HD.TC
Histic Regosolic Turbic Cryosol HR.TC
Static Cryosol Orthic Eutric Static Cryosol OE.SC
Orthic Dystric Static Cryosol OD.SC
Brunisolic Eutric Static Cryosol BRE.SC
Brunisolic Dystric Static Cryosol BRD.SC
Luvisolic Static Cryosol L.SC
Gleysolic Static Cryosol GL.SC
Regosolic Static Cryosol R.SC
Histic Eutric Static Cryosol HE.SC
Histic Dystric Static Cryosol HD.SC
Histic Regosolic Static Cryosol HR.SC
Organic Cryosol Fibric Organic Cryosol FI.OC
Mesic Organic Cryosol ME.OC
Humic Organic Cryosol HU.OC
Terric Fibric Organic Cryosol TFI.OC
Terric Mesic Organic Cryosol TME.OC
Terric Humic Organic Cryosol THU.OC
Glacic Organic Cryosol GC.OC

Source: The Canadian System of Soil Classification (Third Edition)

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