Synthesis of studies of palsa formation underlining the importance of local environmental and physical characteristics

@article{Seppl2011SynthesisOS,
  title={Synthesis of studies of palsa formation underlining the importance of local environmental and physical characteristics},
  author={Matti Sepp{\"a}l{\"a}},
  journal={Quaternary Research},
  year={2011},
  volume={75},
  pages={366 - 370}
}
  • M. Seppälä
  • Published 1 March 2011
  • Geology
  • Quaternary Research
Abstract This review presents a synthesis of four decades of palsa studies based on field experiments and observations mainly in Fennoscandia, as well as laboratory measurements. Palsas are peat-covered mounds with a permanently frozen core; in Finnish Lapland, they range from 0.5 to 7 m in height and from 2 to 150 m in diameter. These small landforms are characteristic of the southern margin of the discontinuous permafrost zone. Palsa formation requires certain environmental conditions: long… Expand
Strong degradation of palsas and peat plateaus in northern Norway during the last 60 years
Abstract. Palsas and peat plateaus are permafrost landforms occurring in subarctic mires which constitute sensitive ecosystems with strong significance for vegetation, wildlife, hydrology and carbonExpand
Lateral thermokarst patterns in permafrost peat plateaus in northern Norway
Abstract. Subarctic peatlands underlain by permafrost contain significant amounts of organic carbon. Our ability to quantify the evolution of such permafrost landscapes in numerical models isExpand
Permafrost Distribution Drives Soil Organic Matter Stability in a Subarctic Palsa Peatland
Palsa peatlands, permafrost-affected peatlands characteristic of the outer margin of the discontinuous permafrost zone, form unique ecosystems in northern-boreal and arctic regions, but are nowExpand
Recent Increases in Permafrost Thaw Rates and Areal Loss of Palsas in the Western Northwest Territories, Canada
Decay of palsas can indicate permafrost status, particularly in regions where air temperatures have increased rapidly in recent decades. Using weather data, annual surveys of active-layer thickness,Expand
Characteristics and fate of isolated permafrost patches in coastal Labrador, Canada
Abstract. Bodies of peatland permafrost were examined at five sites along a 300 km transect spanning the isolated patches permafrost zone in the coastal barrens of southeastern Labrador. Mean annualExpand
Dynamics of peat plateau near the southern boundary of the East European permafrost zone
Detailed study of a peat plateau near the southern boundary of the East European permafrost zone has been performed. The botanical and palynological compositions of the peat to the depth of 10 m, itsExpand
Development and distribution of palsas in Finnmark, Northern Norway, for the period 1950s to 2010s
Palsas are permafrost mounds in mires with a core of ice, widespread situated in the sporadic permafrost zone. A tendency towards decay of palsa mires since the second half of the 20 th century hasExpand
Permafrost active layer
Abstract This article discusses the properties and occurrence of an active layer (AL) in the near-surface of the lithosphere in glacial and periglacial environments. This layer shows a seasonalExpand
Non‐Invasive Geophysical Investigation and Thermodynamic Analysis of a Palsa in Lapland, Northwest Finland
Non-invasive geophysical prospecting and a thermodynamic model were used to examine the structure, depth and lateral extent of the frozen core of a palsa near Lake Peerajarvi in northwest Finland. AExpand
Characteristics and fate of isolated permafrost patches in coastal Labrador, Canada
Bodies of peatland permafrost were examined at five sites along a 300 km transect spanning the isolated patches permafrost zone in the coastal barrens of southeastern Labrador. Mean annual airExpand
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References

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Abstract This work considers the physical properties of peat and their effects on the formation of palsas under cold environmental conditions. Peat samples were taken in winter from the surface of aExpand
Cyclic Development and Thermokarstic Degradation of Palsas in the Mid‐Alpine Zone at Leirpullan, Dovrefjell, Southern Norway
The palsas of Leirpullan are developed in deltaic sands and silts in the zone of alpine permafrost at an altitude of 1437 m (estimated mean annual air temperature −2.7°C). Five mounds that representExpand
The role of buoyancy in palsa formation
Abstract The formation of a palsa is based on the thermal properties of peat. Frozen wet peat has a high thermal conductivity, and therefore cold can penetrate deep into peat layers if the snow coverExpand
A mathematical approach to modelling palsa formation: Insights on processes and growth conditions
Abstract A one-dimensional heat and mass transfer model was designed to simulate the long term aggradation of permafrost and the buildup of segregated ice that take place during the formation ofExpand
Growth and decay of palsas and peat plateaus in the Macmillan Pass–Tsichu River area, Northwest Territories, Canada
Macmillan Pass, at 1350 m asl (above sea level), is located in the Selwyn Mountains at the Yukon–Northwest Territories border (63 °15′N, 130°02′W). This area lies within the discontinuous butExpand
An experimental study of the formation of palsas
A hypothesis of palsa formation has been tested experimentally in the field in northern Finland. Snow layers were deliberately removed from a peat bog surface several times during three winters. ThisExpand
Preliminary studies on the ecology of palsa mounds in northern Ontario
TLDR
From vegetational analysis, hummock and palsa morphology, and radiocarbon dating, evidence is given for a recent origin under climatic conditions similar to the present as well as evidence that decreased penetration of heat during summer asso... Expand
"The international structure of a pala and a peat plateau in the Rivière Boniface region, Québec: Interferences on the formation of ice segregation mounds"
The internal structure of a 5.7 m high palsa was studied through a pattern of closely spaced drill holes in permafrost along two orthogonal section lines. Holes were also drilled on a 1.3 m high peatExpand
Collapse of permafrost mounds along a subarctic river over the last 100 years (northern Québec)
Widespread permafrost decay is currently occurring in the northern hemisphere. In subarctic Quebec, most permafrost mounds are located in peatlands in the form of palsas and peat plateaus. TheExpand
Accelerated thawing of subarctic peatland permafrost over the last 50 years
[1] In this study we provide a quantification of the main patterns of change of a subarctic peatland caused by permafrost decay monitored between 1957 and 2003. Up-thrusting of the peatland surfaceExpand
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