Geoelectrical soundings in the Combeynot Massif (French Alps) : Characterisation of Alpine permafrost and geodynamics of the Southern Alps .
0
Citation
0
Reference
10
Related Paper
Keywords:
geodynamics
Massif
Cite
Abstract Geomorphological observations, geoelectrical soundings and photogrammetric measurements of surface movement on the Muragl glacier forefield were used to obtain an integrative analysis of a highly complex glacial and periglacial landform consisting of a push moraine, creeping permafrost and permafrost‐free glacial till in close proximity. Electrical resistivity tomography is considered as an important multifunctional geophysical method for research in periglacial permafrost related environments. Joint application with measurements of surface displacements offers a promising tool for investigating periglacial landforms related to ice‐rich permafrost for a more comprehensive characterization of permafrost characteristics and geomorphological interpretation of periglacial morphodynamics. The patchy permafrost distribution pattern described in this paper is determined by several factors, including the sediment characteristics, the snow cover distribution and duration, the aspect and the former glacier distribution and thermal regime. Recent and modern permafrost dynamics within the glacier forefield comprise aggradation, degradation and permafrost creep. Copyright © 2007 John Wiley & Sons, Ltd.
Landform
Glacial landform
Rock glacier
Electrical Resistivity Tomography
Cite
Citations (91)
ABSTRACT A series of systematic shear tests were performed using an inclinable shear box containing a coarse‐grained active layer overlying a fine‐grained permafrost layer, a stratigraphy observed in the field. The angle of mobilised interface friction Φ mob was determined as depending on the grain size of the active layer and the permafrost, the water content of the active layer and the ice content of the permafrost. Φ mob was found to be 8° lower for ice‐free permafrost compared to permafrost containing ice. This result implies a possible long‐term decrease of active‐layer slope stability on scree slopes in Alpine permafrost terrain under warming conditions. Copyright © 2012 John Wiley & Sons, Ltd.
Active layer
Cite
Citations (10)
"The Rhenish Massif. Structure, evolution, mineral deposits and present geodynamics." Geologiska Föreningen i Stockholm Förhandlingar, 110(4), p. 426
Massif
geodynamics
Cite
Citations (2)
Massif
geodynamics
Cite
Citations (0)
Abstract This chapter examines the warming of permafrost found in the Earth’s coldest regions. It relates how this warming results in the release of large amounts of methane gas from gas hydrates buried in frozen grounds and discusses the implications for climate change of this release. The chapter outlines the categories of permafrost and the role that thawing and freezing cycles play in the local environment. It also describes how to use online GIS tools to locate permafrost regions on the Earth. Finally, the chapter reviews the common impacts of melting permafrost such as subsidence, sinkholes, destruction of infrastructure, as well as the possible release of human and animal disease agents.
Sinkhole
Thermokarst
Cite
Citations (0)
Abstract The areas studied display a rich periglacial geomorphology. The effects of seasonal and perennial ground frost are visible in the form of widespread solifluction phenomena, patterned ground and numerous rock glaciers. Soil and rock temperatures have been recorded, and permafrost distribution has been partly checked in selected areas with measurements of the basal snow temperature, and using geoelectrical and hammer seismic soundings. Permafrost is widespread on northerly exposed slopes, with a thickness of several decametres at 3100m a.s.1. Below 2800 m a.s.1. patchy permafrost occurs. A model for vertical permafrost distribution is presented and an altitude of 3500 m a.s.1. is suggested for the lower limit of continuous permafrost. As a result of aspect, soil and rock temperature fluctuations are different on northern and southern slopes. This induces differences in vegetation cover, debris production and geomorphological processes.
Solifluction
Rock glacier
Frost weathering
Frost heaving
Frost (temperature)
Snowmelt
Soil cover
Cite
Citations (25)
Siberia and the Russian Far East contain about 75% of the country's hydrocarbon and mineral resources. These regions pose many engineering and environmental problems for economic development due to the cold climate and difficult geologic conditions, including the occurrence of permafrost. One of the major challenges in permafrost areas is to maintain the stability of both individual structures and large-scale engineering projects. The use of natural cryogenic resources of the Earth is proposed here as one possible solution.
Mineral resource classification
Cite
Citations (0)
A detailed geomorphological map of the Mt. Babia Góra Massif (1725 m a.s.l.), at a scale 1:10,000 is presented. A slope, glacial, periglacial and fluvial features were mapped on the base of the coupled field studies and LiDAR DEM analyses. This study underlines the complexity of rock slope failures (RSFs), in shaping the morphology of compact and isolated upland, exhibiting one of the highest incidences of RSFs yet recorded in Europe (29% for a whole massif, and 45% for the north face). A total of 212 RSFs were mapped of which 18 failures are large landslides (>0.25 km2), among them is one of the largest known (2.6 km2 and 150 × 106 m3) in the Polish Flysch Carpathians. The mapping and Schmidt-hammer results shed light on the problem of glacial relief of the massif, documenting the remnants of glacial deposits beyond the tongues of landslides in the Szumiąca Woda valley.
Massif
Flysch
Colluvium
Schmidt hammer
Cite
Citations (16)
Arctic permafrost caps vast amounts of old, geologic methane (CH4) in subsurface reservoirs. Thawing permafrost opens pathways for this CH4 to migrate to the surface. However, the occurrence of geologic emissions and their contribution to the CH4 budget in addition to recent, biogenic CH4 is uncertain. Here we present a high-resolution (100 m × 100 m) regional (10,000 km²) CH4 flux map of the Mackenzie Delta, Canada, based on airborne CH4 flux data from July 2012 and 2013. We identify strong, likely geologic emissions solely where the permafrost is discontinuous. These peaks are 13 times larger than typical biogenic emissions. Whereas microbial CH4 production largely depends on recent air and soil temperature, geologic CH4 was produced over millions of years and can be released year-round provided open pathways exist. Therefore, even though they only occur on about 1% of the area, geologic hotspots contribute 17% to the annual CH4 emission estimate of our study area. We suggest that this share may increase if ongoing permafrost thaw opens new pathways. We conclude that, due to permafrost thaw, hydrocarbon-rich areas, prevalent in the Arctic, may see increased emission of geologic CH4 in the future, in addition to enhanced microbial CH4 production.
Cite
Citations (65)