Geoscience Reference
In-Depth Information
being of moderate importance, and three asterisks (***) as being of major importance
in Antarctica (Table 9.7 ). The table lists each of the ice-free regions and subdivides
them, where appropriate, into coastal and inland (mountain) sub-regions. Processes
such as rubifi cation, salinization, desert pavement formation, and permafrost devel-
opment operate to the greatest extent in the inland mountains of regions 1, 3, 5a, 5b,
6 and possibly 7. Calcifi cation is not a dominant process and occurs primarily in
coastal areas of regions 2, 3, 5, and 7. Soil organic matter accumulation, acidifi ca-
tion, hydromorphism, phosphatization, paludifi cation, and pervection occur in
coastal areas of regions 1 through 4, 7, and 8 but also in the mountains of the
Antarctic Peninsula. In Antarctica, as in the Arctic, hydromorphism leads to reduc-
tive Eh values but no apparent redoximorphic features or gleying. Sulfurization is
restricted to areas with sulfi de-enriched parent materials, such as King George
Island and Seymour Island. Podzolization is restricted to abandoned penguin rook-
eries in coastal areas of regions 4 and 8 but may occur to a limited extent in other
ice-free areas.
Figure 9.5 shows a gradient in soil-forming processes in Antarctica. Whereas
processes such as acidifi cation, clay formation, brunifi cation (melanization), organic
matter accumulation, redoximorphism, and podzolization decrease from the subant-
arctic tundra through the subpolar desert to the cold desert inland mountains, pro-
cesses such as salinization, alkalization, desert pavement formation, and permafrost
thickness increase along the gradient.
9.5
Soil Classifi cation and Geography
Typic Anhyorthels are the dominant soil subgroup comprising nearly 15,000 km 2 ,
or 30 % of the soils in Antarctica (Table 9.8 ). These soils occur primarily in cen-
tral and southern Victoria Land (region 5b), but also in the Thiel and Pensacola
Mountains and Shackleton Range (region 5a), the Prince Charles Mountains
(region 3) and the mountains of Queen Maud Land (region 1). Typic Haploturbels
and Typic Anhyturbels occupy 14 and 13 % of the soils of ice-free regions of
Antarctica, respectively. Most abundant in central Victoria Land, they are com-
mon in most mountainous regions of Antarctica. Soils in lithic subgroups com-
prised only 15 % of the soils; however, in the mountains of Antarctica, especially
regions 1, 3, 5a, 5b, 6, 7, and 8, we were unable to differentiate the Rockland land
type from soils in lithic subgroups so that we have probably underestimated the
areal distribution of lithic soils. Typic Gelorthents occupy about 8 % of the ice-
free areas of Antarctica, mainly in Palmer and Graham Lands but also in the SSI
and SOI (region 8).
Forty-four percent of the soils of Antarctica are Orthels, gelisols that show mini-
mal evidence of cryoturbation and occur in dry landscape positions; 36 % of the
soils are Turbels showing cryoturbation in more moist landscape positions
(Table 9.9 ). Only 16 % of the soils of Antarctica lack permafrost in the control sec-
tion and are classifi ed as Entisols (Gelorthents), Inceptisols (Haplogelepts,
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