Abstract
In Japan research studies on periglacial smooth slopes have increased in number since the early 1970s. This increment is considered to be reflected by the development of Quaternary research in the 1960's. The Research Group for Alpine Geomorphology, mainly composed of young geomorphologists, has played an important role in the development of these studies, which were mostly carried out in the alpine zone of the Japanese Alps. The research began with field investigations such as measurements of grain-size distribution of slope deposits and measurements of rates of periglacial debris movement. In succession, the processes of debris movement and slope forms were examined. These quantitative studies covered aspects insufficiently investigated in European studies performed by Spreitzer and his colleagues. It was revealed that the grain-size characteristics and the stability of slope deposits largely depended on differences in the lithologic features of each area, and the chacteristics of surface materials affected the vegetational distribution. Some chronological studies revealed that debris production from bedrock had occurred even in the Late Glacial age and the Neoglaciation age. The importance of fossil periglacial slope studies is increasing for environmental reconstruction of the Last Glacial Age. Studies of plant ecology were also conducted on periglacial smooth slopes. Based on recent experiments both in the laboratory and in the field, studies of the mechanism of frost shattering are under way. They have come to support the adsorption force theory. The mechanism of formation of periglacial block slopes and the convexity of crest slopes are themes which require investigation in the future.
