Permafrost age and thickness near Adventfjorden, Spitsbergen<sup>1</sup>

Harada, Koichiro; Yoshikawa, Kenji

doi:10.1080/10889379609377607

Cited by 25 publications

(27 citation statements)

References 7 publications

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“…The permafrost thickness in West Spitsbergen has been in the range of 3-100 m in low altitude valleys since 3000 calendar years BP (Harada and Yoshikawa, 1996;Humlum, 2005). Kristensen et al (2008) have modeled the subsea permafrost distribution in Van Mijenfjorden (central Spitsbergen).…”

Section: Gas Hydrates Subsea Permafrost and Pockmarksmentioning

confidence: 98%

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Roy

Hovland²,

Noormets³

et al. 2015

Marine Geology

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This study analyses pockmark morphology and their spatial distribution in Isfjorden relative to seabed morphology, bedrock geology, fault systems, glacial landforms and processes using multibeam bathymetric data. It provides insight into the possible mechanisms of pockmark formation, high density pockmark field evolution, and fluid migration pathways. A total of 1304 pockmarks occur in the Isfjorden at water depths of 40 to 320 m, varying from circular to elongate in plan-view. Their diameter ranges from 14 to 265 m and their depths from 1 to 11 m. Elongate pockmarks are dominant in the Isfjordbanken and outer Isfjorden where the seafloor is influenced by the West Spitsbergen Current. The West Spitsbergen fold-and-thrust belt and other fault systems subcropping at the Isfjorden seafloor correlate spatially with the high density pockmark zones. The pockmarks are preferentially located on the marine sediments draping the bedrock of Isfjorden fjord system. They are most abundant in the areas underlain by Jurassic-Cretaceous and the Triassic-Lower Jurassic bedrock. Pockmarks found ahead of submarine slope failures may have formed due to dewatering of soft sediments as a result of rapid increase of overpressure caused by deposition of glacigenic debris lobes. Fault conduits, potential source rock and thin postglacial sediment layers are found to be crucial for the formation of pockmarks. Modeling results of the near-shore subsea permafrost and potential gas hydrate stability zone imply thawing permafrost and gas hydrate dissociation as additional possible mechanisms for pockmark formation in Isfjorden.

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Section: Gas Hydrates Subsea Permafrost and Pockmarksmentioning

confidence: 98%

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Roy

Hovland²,

Noormets³

et al. 2015

Marine Geology

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“…The electrical resistivity of soil depends on the soil type, temperature, water content, porosity, and salinity. In general, the resistivity (r) values of frozen soil are 10 -1000 times greater than those of unfrozen or brine soils [Harada and Yoshikawa, 1996]. DC resistivity sounding used four electrodes for measurement.…”

Section: Resistivity Soundingmentioning

confidence: 99%

Comparison of geophysical investigations for detection of massive ground ice (pingo ice)

et al. 2006

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[1] Six different geophysical investigations, (1) ground-penetrating radar, (2) DC resistivity sounding, (3) seismic refraction, (4) very low frequency (VHF) electromagnetic, (5) helicopter borne electromagnetic (HEM), and (6) transient electromagnetic (TEM) techniques, were employed to obtain information on the ice body properties of pingos near Fairbanks, Alaska. The surface nuclear magnetic resonance (NMR) data were also compared from similar sites near one of the study pingos. The geophysical investigations were undertaken, along with core sampling and permafrost drilling, to enable measurement of the ground temperature regime. Drilling (ground truthing) results support field geophysical investigations, and have led to the development of a technique for distinguishing massive ice and overburden material of the permafrost. The twodimensional DC resistivity sounding tomography and ground-penetrating radar profiling are useful for ice detection under heterogeneous conditions. However, the DC resistivity sounding investigation required high-quality ground contact and less area coverage. The active layer thickness and the homogeneous horizontal structure of the overburden material are important parameters influencing detection of massive ice in permafrost for most methods such as seismic, TEM, or surface NMR.

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“…Spatial variations of permafrost state in Svalbard have been investigated by multiple researchers. Ground thermal conditions in Kapp Line, Svea, Ny-Ålesund and in Longyearbyen surroundings have been described by Christiansen et al (2010), in Longyearbyen by Harada and Yoshikawa (1998), in Petuniabukta by Rachlewicz and Szczuciński (2008), in Bellsund by Marsz et al (2013b), and in Kaffiøyra Plain by Sobota and Nowak (2014). Snow thicknesses on SW Spitsbergen are highly variable in the accumulation period due to the strong wind drift and thaws that occur seasonally during winter time (Luks et al 2011;Marsz et al 2013b).…”

Section: Methodsmentioning

confidence: 99%

Modelling of the thermal regime of permafrost during 1990–2014 in Hornsund, Svalbard

Wawrzyniak

Osuch

Napiórkowski

et al. 2016

Polish Polar Research

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Abstract:The thermal state of permafrost is a crucial indicator of environmental changes occurring in the Arctic. The monitoring of ground temperatures in Svalbard has been carried out in instrumented boreholes, although only few are deeper than 10 m and none are located in southern part of Spitsbergen. Only one of them, Janssonhaugen, located in central part of the island, provides the ground temperature data down to 100 m. Recent studies have proved that significant warming of the ground surface temperatures, observed especially in the last three decades, can be detected not only just few meters below the surface, but reaches much deeper layers. The aim of this paper is evaluation of the permafrost state in the vicinity of the Polish Polar Station in Hornsund using the numerical heat transfer model CryoGrid 2. The model is calibrated with ground temperature data collected from a 2 m deep borehole established in 2013 and then validated with data from the period 1990-2014 from five depths up to 1 m, measured routinely at the Hornsund meteorological station. The study estimates modelled ground thermal profile down to 100 m in depth and presents the evolution of the ground thermal regime in the last 25 years. The simulated subsurface temperature trumpet shows that multiannual variability in that period can reach 25 m in depth. The changes of the ground thermal regime correspond to an increasing trend of air temperatures observed in Hornsund and general warming across Svalbard.

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Permafrost age and thickness near Adventfjorden, Spitsbergen¹

Cited by 25 publications

References 7 publications

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Comparison of geophysical investigations for detection of massive ground ice (pingo ice)

Modelling of the thermal regime of permafrost during 1990–2014 in Hornsund, Svalbard

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Permafrost age and thickness near Adventfjorden, Spitsbergen1

Cited by 25 publications

References 7 publications

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Seepage in Isfjorden and its tributary fjords, West Spitsbergen

Comparison of geophysical investigations for detection of massive ground ice (pingo ice)

Modelling of the thermal regime of permafrost during 1990–2014 in Hornsund, Svalbard

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Permafrost age and thickness near Adventfjorden, Spitsbergen¹