Geoscience Reference
In-Depth Information
Fig. 4.8
Soil organic C
within (
a
) a high-centered
polygon in the Barrow,
Alaska Environmental
Observatory and (
b
) a
fl at-centered polygon at the
former International
Biological Program Tundra
Biome site, Barrow,
AK. Values to the
right
of
each horizon are reported in
kg C m
−2
year
−1
and the
profi le sum is kg m
−3
(Bockheim et al.
1999
)
texture, soil moisture, and soil temperature. Most earth hummocks in the Mackenzie
River valley have formed during the last 5,000 year.
4.3.1.4
Frost Mounds
Frost mounds are peaty permafrost mounds with a core of alternating layers of
segregated ice and peat or mineral soil material. Palsas, a type of these features,
have been studied extensively by Seppälä (
2006
). Frost mounds are typically
between 1 and 10 m in height and a few meters to 100 m in diameter. Most, but
not all, frost mounds occur in the discontinuous permafrost zone. Frost mounds
form from permafrost aggradation at an active-layer-permafrost contact zone or
