The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

Norikazu Matsuoka - One of the best experts on this subject based on the ideXlab platform.

  • Climate and material controls on Periglacial soil Processes: Toward improving Periglacial climate indicators
    Quaternary Research, 2011
    Co-Authors: Norikazu Matsuoka
    Abstract:

    One of the distinguished efforts of A.L. Washburn was to reconstruct mean annual air temperature using Periglacial features as climate indicators. This paper reviews existing Periglacial indicators and proposes a strategy to improve their thermal resolution based on recent Periglacial Process studies, with a focus on solifluction and thermal contraction cracking and associated landforms/structures. Landforms resulting from solifluction reflect both the depth subjected to freeze–thaw and the thickness of frost-susceptible soils. The thickness of a solifluction structure can be used to infer the dominant freeze–thaw regime and minimum seasonal frost depth. Ice-wedge pseudomorphs have limited potential as a climate indicator because (1) they mainly reflect extreme winter temperatures, (2) their thermal thresholds depend on the host material, and (3) they need to be distinguished from frost wedges of other origin produced under different thermal and/or material conditions. Monitoring studies of currently active ice wedges suggest that ice-wedge cracking requires a combination of low temperature and large temperature gradients in the frozen active layer. Further field monitoring of Periglacial Processes and their controlling factors under various climate conditions and in various materials are needed, however, to improve the resolution of Periglacial paleoclimate indicators.

Yan Fuhua - One of the best experts on this subject based on the ideXlab platform.

  • Periglacial Process and Pleistocene environment in northern China
    AAPG Bulletin, 1991
    Co-Authors: Guo Xudong, Liu Dongsheng, Yan Fuhua
    Abstract:

    In the present time, five kinds of Periglacial phenomena have been defined: ice wedges, Periglacial involutions, congelifolds, congeliturbations, and loess dunes. From the stratigraphical and geochronological data, the Periglacial Process is divided into six stages. (1) Guanting Periglacial stage, characterized by the congeliturbative deposits that have developed in early Pleistocene Guanting loess-like formation. Paleomagnetic dating gives 2.43 Ma B.P. (2) Yanchi Periglacial stage, characterized by the congelifold that has developed in middle Pleistocene Yanchi Lishi loess formation. Paleomagnetic dating gives 0.50 Ma B.P. (3) Zhaitang Periglacial stage (II), characterized by the Periglacial involutions that have developed in lower middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.30 Ma B.P. (4) Zhaitang Periglacial state (I), characterized by the ice (soil) wedge that has developed in upper-middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.20 Ma B.P. (5) Qiansangyu Periglacial stage (II), characterized by the ice (sand) wedges that has developed in late Pleistocene Malan loess formation. Paleomagnetic dating gives 0.13 Ma B.P. (6) Qiansangyu Periglacial stage (I), characterized by the ice (soil) wedge that has developed in late Pleistocene Malan loess-like formation. Thermoluminescent dating gives 0.018 Ma B.P. Spore-pollen composition analysis shows that the savannah steppe environment prevailed in northern Chinamore » during Pleistocene Periglacial periods. These fossilized Periglacial phenomena indicate a rather arid and windy Periglacial environment with a mean annual temperature estimated some 12-15C colder than that in the present.« less

Hanne Hvidtfeldt Christiansen - One of the best experts on this subject based on the ideXlab platform.

  • Periglacial Process research for improved understanding of climate change in Periglacial environments
    2010
    Co-Authors: Hanne Hvidtfeldt Christiansen
    Abstract:

    It is the complex relationship between climate, micro-climate and local geomorphological, geological and ecological conditions, which controls Periglacial Processes. In several cases local erosion or deposition will affect the rates of landform change significantly more than any climate change. Thus detailed Periglacial Process studies will sophisticate the predictions of how Periglacial landscapes can be expected to respond to climatic changes, and be built into Earth System Modelling. Particularly combining direct field observations and measurements with remote sensing and geochronological studies of Periglacial landforms, enables a significantly improved understanding of Periglacial Process rates. An overview of the state of research in key Periglacial Processes are given focusing on ice-wedges and solifluction landforms, and seasonal ground thermal dynamics, all with examples from the high Arctic in Svalbard. Thermal contraction cracking and its seasonal meteorological control is presented, and potential thermal erosion of ice-wedges leading to development of thermokarst is discussed. Local and meteorological controls on solifluction rates are presented and their climatic control indicated. Seasonal ground thermal Processes and their dependence on local vegetation and snow conditions as affecting active layer depths and top permafrost thermal regimes are discussed. An overview of other important Periglacial Processes such as weathering, rock glacier, pingo and palsa dynamics and their climatic and/or local condition controls are given. Finally an overall discussion on how Periglacial Processes can affect rock slope stability in Periglacial environments close to the permafrost boundary is introduced, with an example from northern Norway.

Guo Xudong - One of the best experts on this subject based on the ideXlab platform.

  • Periglacial Process and Pleistocene environment in northern China
    AAPG Bulletin, 1991
    Co-Authors: Guo Xudong, Liu Dongsheng, Yan Fuhua
    Abstract:

    In the present time, five kinds of Periglacial phenomena have been defined: ice wedges, Periglacial involutions, congelifolds, congeliturbations, and loess dunes. From the stratigraphical and geochronological data, the Periglacial Process is divided into six stages. (1) Guanting Periglacial stage, characterized by the congeliturbative deposits that have developed in early Pleistocene Guanting loess-like formation. Paleomagnetic dating gives 2.43 Ma B.P. (2) Yanchi Periglacial stage, characterized by the congelifold that has developed in middle Pleistocene Yanchi Lishi loess formation. Paleomagnetic dating gives 0.50 Ma B.P. (3) Zhaitang Periglacial stage (II), characterized by the Periglacial involutions that have developed in lower middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.30 Ma B.P. (4) Zhaitang Periglacial state (I), characterized by the ice (soil) wedge that has developed in upper-middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.20 Ma B.P. (5) Qiansangyu Periglacial stage (II), characterized by the ice (sand) wedges that has developed in late Pleistocene Malan loess formation. Paleomagnetic dating gives 0.13 Ma B.P. (6) Qiansangyu Periglacial stage (I), characterized by the ice (soil) wedge that has developed in late Pleistocene Malan loess-like formation. Thermoluminescent dating gives 0.018 Ma B.P. Spore-pollen composition analysis shows that the savannah steppe environment prevailed in northern Chinamore » during Pleistocene Periglacial periods. These fossilized Periglacial phenomena indicate a rather arid and windy Periglacial environment with a mean annual temperature estimated some 12-15C colder than that in the present.« less

Liu Dongsheng - One of the best experts on this subject based on the ideXlab platform.

  • Periglacial Process and Pleistocene environment in northern China
    AAPG Bulletin, 1991
    Co-Authors: Guo Xudong, Liu Dongsheng, Yan Fuhua
    Abstract:

    In the present time, five kinds of Periglacial phenomena have been defined: ice wedges, Periglacial involutions, congelifolds, congeliturbations, and loess dunes. From the stratigraphical and geochronological data, the Periglacial Process is divided into six stages. (1) Guanting Periglacial stage, characterized by the congeliturbative deposits that have developed in early Pleistocene Guanting loess-like formation. Paleomagnetic dating gives 2.43 Ma B.P. (2) Yanchi Periglacial stage, characterized by the congelifold that has developed in middle Pleistocene Yanchi Lishi loess formation. Paleomagnetic dating gives 0.50 Ma B.P. (3) Zhaitang Periglacial stage (II), characterized by the Periglacial involutions that have developed in lower middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.30 Ma B.P. (4) Zhaitang Periglacial state (I), characterized by the ice (soil) wedge that has developed in upper-middle Pleistocene Lishi loess formation. Paleomagnetic dating gives 0.20 Ma B.P. (5) Qiansangyu Periglacial stage (II), characterized by the ice (sand) wedges that has developed in late Pleistocene Malan loess formation. Paleomagnetic dating gives 0.13 Ma B.P. (6) Qiansangyu Periglacial stage (I), characterized by the ice (soil) wedge that has developed in late Pleistocene Malan loess-like formation. Thermoluminescent dating gives 0.018 Ma B.P. Spore-pollen composition analysis shows that the savannah steppe environment prevailed in northern Chinamore » during Pleistocene Periglacial periods. These fossilized Periglacial phenomena indicate a rather arid and windy Periglacial environment with a mean annual temperature estimated some 12-15C colder than that in the present.« less