Geoscience Reference
In-Depth Information
2011
). Soils with salic horizons (salts more soluble than gypsum) are common
under anhydrous conditions in central and southern Victoria Land, Antarctica
(Bockheim
1997
). Spodic horizons contain illuvial organic matter and Al (with or
without Fe), are dark-colored, and are low in base cations. Spodic horizons have
been reported in the lower Kolyma River valley (Jakobsen et al.
1996
; Alekseev
et al.
2003
), in northeast Greenland (Ugolini
1966
), and in abandoned penguin
rookeries in East Antarctica (Beyer and Bölter
2000
) and King George Island
(Bölter et al.
1997
), Antarctica. Soils with spodic horizons are common in the sub-
alpine zone in mountains underlain by permafrost (Burns
1990
; Skiba
2007
).
In addition to diagnostic horizons, cryosols contain a number of distinguishing
characteristics or properties, as defi ned in ST. Several of these properties are unique
to cryosols, including anhydrous conditions (less than 3 % moisture by weight),
cryoturbation (frost mixing and sorting), gelic materials (organic or mineral materi-
als showing cryoturbation), glacic layers (massive ice or ground ice 30 cm or more
thick), permafrost (remains below 0 °C for 2 or more yr in succession), and gelic
soil-temperature regimes (mean annual soil temperature at 50 cm at or below 0 °C).
There are several other important diagnostic characteristics that have been iden-
tifi ed in cryosols. The Coeffi cient of Linear Extensibility (COLE) is manifested in
many cryosols by the characteristic of dilatancy (Jones et al.
2010
; Karavaeva
2013
).
MacNamara and Tedrow (
1966
) characterized a Grumusol (Vertisol-like soil) with
permafrost near Umiat, Alaska (69°23
W). The soil featured gilgai
topography and desiccation cracks 2-3 cm in width and 8-20 cm in depth. The soil
featured salt segregations on ped surface, a strongly granular structure, abundant
water-soluble Na and SO
4
(thenardite), and clay concentrations ranging between 76
and 82 % that were dominantly smectites.
Volcanic glass is present in permafrost-affected soils of the Kamchatka Peninsula,
Russia and in soils on Deception Island in the South Shetland Group off the Antarctic
Peninsula. However, in both cases the glass has not weathered suffi ciently to yield
andic soil properties.
Cryosols either have an aquic or a udic soil-moisture regime. cryosols in mari-
time Antarctica, especially on Seymour Island contain sulfi dic materials and a sul-
furic horizon (de Souza et al.
2012
).
′
N, 152°10
′
6.4
Summary
Soil classifi cation schemes have moved from genetic or zonal systems to natural or
technical systems with the publication of the Seventh Approximation (1960). Soils
underlain by permafrost exist in a separate category at the highest level in the
Canadian and WRB systems (cryosols) and
Soil Taxonomy
(ST) (Gelisols). In ST
the primary criteria are the occurrence of gelic materials, which are organic or min-
eral materials that are subjective to cryoturbation, cryodesiccation, and ice segrega-
tion, as well as the existence of permafrost within 1-2 m of the ground surface.
Other diagnostic horizons are found in Gelisols/cryosols but these play a lesser role
than the presence of gelic materials.
