Geoscience Reference
In-Depth Information
assessment (Lovejoy 2013 ) showed that bacteria, archaea and single-celled
eukaryota (protists) are ubiquitous and diverse members of biological communities
in Arctic soils. Humans have had a major impact of terrestrial ecosystems in the
circumarctic; this topic will be considered in Chaps. 12 and 13 .
8.2.3
Relief
The relief in the arctic archipelagos, coastal plains, lowlands and along the river
terraces is fl at to undulating with elevations generally below 200 m. In the Arctic
Foothills and inland plateaus the relief is steeper but the elevations are commonly
below 500 m. The mountains have even steeper relief and higher elevations, such as
the Brooks Range of Alaska, the Rocky Mountains of Alaska and Canada, the
Richardson Mountains of Canada, and the Yablonai-Sayan-Stanovoi Mountains of
Siberia. However, these areas are considered in Chap. 10 .
8.2.4
Parent Materials and Time
Cryosols in the circumarctic are derived from a variety of parent materials, includ-
ing marine and lacustrine sediments in the northern Eurasian and North American
coastal plains, loess (yedoma in central Siberia and the Russian Far East) and north-
ern Alaska, glacial deposits, alluvium along the large arctic rivers (such as the Ob,
Yenisey, Lena, and Kolyma rivers in Russia, the Yukon in Alaska and Canada, and
Mackenzie river in Canada), and sand dunes and sand plains in the Arctic Coastal
Plain (Table 8.2 ). Volcanic ejecta are an importance parent material in arctic por-
tions of the circumpacifi c belt. Peat deposits are common throughout the circumarc-
tic, especially in the Mackenzie River delta. Most of these materials are of Last
Glacial Maximum (ca. 12-20 ky BP) age or younger. In the Arctic Coastal Plain the
thaw-lake cycle has interrupted soil formation since at least the last glaciation
(Hinkel et al. 2003 ).
Table 8.2 Common parent materials in the circumarctic lowlands and hills
Zone
Russia
Canada
Alaska
Greenland
High
Arctic
Marine, alluvium,
sand dunes & plains
Lacustrine, alluvium,
colluvium, marine
[not present]
Glacial,
colluvium
Mid-
Arctic
Loess, glacial,
alluvium, colluvium,
volcanic ash
Lacustrine, alluvium,
sand dunes & plains
Marine, lacustrine,
alluvium, sand dunes
& plains, loess
Glacial,
alluvium
Low
Arctic
Alluvium, peat
Peat, lacustrine,
alluvium
Loess, glacial, peat,
lacustrine, volcanic ash
Glacial,
alluvium,
 
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