Turbic Cryosol (TC)

These are Cryosolic soils that have developed primarily in mineral material and have marked evidence of cryoturbation (Harris et al. 1988). They generally occur on patterned ground, which includes such cryogenic forms as sorted and nonsorted circles, nets, polygons, stripes, and steps in stony or coarse-textured material and nonsorted units such as earth hummocks in medium- and fine-textured materials. The pedon includes all elements of the microtopography in cycles less than 7 m in width. Processes include sorting of different-sized particles and mixing of both mineral and organic material from different horizons. Organic (Oy) or organic-rich, mineral horizons (Ahy) are characteristically present in the region of the permafrost table (upper surface of permafrost layer), and there is generally a buildup of ice in the upper part of the permafrost layer.

Turbic Cryosols are mineral soils that have permafrost within 2 m of the surface and show marked evidence of cryoturbation laterally within the active layer, as indicated by disrupted or mixed or broken horizons, or displaced material or a combination of both.

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.

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Orthic Dystric Turbic Cryosol (OD.TC)

Common horizon sequence: Om, Bmy, BCy, Cgy, Omy, Cz

These acidic Turbic 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 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 less than 5.5 throughout the B horizons.
  4. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table.

Orthic Dystric 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.

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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.

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Brunisolic Dystric Turbic Cryosol (BRD.TC)

Common horizon sequence: Om, Bm, Bmy or BCy, Cgy, Omy, Cz

These acidic Turbic 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, 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 less than 5.5 throughout the B horizons.
  4. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table.

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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

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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.

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Histic Eutric Turbic Cryosol (HE.TC)

Common horizon sequence: Om, Ah, Bmy or Bm (or both) or Cgy, Cz

These Turbic Cryosols have a relatively high degree of base saturation, as indicated by their pH, and thick (>15 cm) organic (peaty) horizons in the upper 1 m of the solum. They are identified by the following properties:

  1. These soils have either a continuous surface organic horizon (Ohy, Hy) ranging in thickness from >15 to 40 cm, or a combination of surface and subsurface organic horizons >15 cm thick.
  2. They have a Bm or Bmy horizon, or both, which is continuous over the imperfectly to well-drained part of the pedon.
  3. 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.
  4. These soils have a pH (0.01 M CaCl2) of 5.5 or greater in some or all of the B horizons.
  5. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table.

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Histic Dystric Turbic Cryosol (HD.TC)

Common horizon sequence: Om, Ah, Bmy or Bm (or both) or Cgy, Cz

These acidic Turbic Cryosols have a low degree of base saturation, as indicated by their pH, and thick (>15 cm) organic (peaty) horizons in the upper 1 m of the solum. They are identified by the following properties:

  1. These soils have either a continuous surface organic horizon (Ohy, Hy) ranging in thickness from >15 to 40 cm, or a combination of surface and subsurface organic horizons >15 cm thick.
  2. They have a Bm or Bmy horizon (or both), which is continuous over the imperfectly to well-drained part of the pedon that is relatively unaffected by cryoturbation.
  3. 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.
  4. These soils have a pH (0.01 M CaCl2) of less than 5.5 throughout the B horizons.
  5. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table.

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Histic Regosolic Turbic Cryosol (HR.TC)

Common horizon sequence: Om, Cy, Cgy, Cz

These Turbic Cryosols have developed on recently deposited or strongly cryoturbated soil materials. They have thick (>15 cm) organic (peaty) horizons in the upper 1 m of the solum. They are identified by the following properties:

  1. These soils have either a continuous surface organic horizon (Ohy, Hy) ranging in thickness from >15 to 40 cm, or a combination of surface and subsurface organic horizons >15 cm thick.
  2. They lack B horizons.
  3. Cryoturbation is manifested by oriented stones, displacement of materials, and sorting.
  4. The surface horizons are not strongly gleyed, but there is usually a gleyed horizon immediately above the permafrost table.

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Note: Diagnostic horizons are underlined.