抄録
Seventy years have passed since glacial features were studied for the first time in Japan in 1902. With the progress of the Quaternary research, the study has gradually been activated after the War, involving a number of scientific disciplines. This symposium was intended to focus upon gaining common understanding of some of the questions concerning the problems of glacial geomorphology in Japan at the present time. Seven papers were read in the forenoon session: 1) Toshio Okayama: An outline of history of studies on glacial geomorphology in Japan, 2) Tomoya Iozawa: Patterns and distributions of glacial landforms, 3) Yugo Ono: Cirque topography of the Japanese Alps, 4) Kiyoshi Sekine: Microtopography of the cirque bottom, 5) Masahide Shiki: Glacial landforms and climatic terraces, 6) Shoji Horie: Ice Age chronology in terms of lake sediments, 7) Norio Fuji: Climatic fluctuation of the Ice Age and the Post-Ice Age in terms of palynological data.
Four and a half hours of the afternoon session, that followed the presentation of the seven reporters, were truly lively and substantial. More than two hundred participants attended the session, and the discussion was full of significant comments and opinions, which were given by the participants as well as by nine commentators. The discussion can be summarized to consist of two main themes. The one is a problem of identification of glacial landforms. This contains four sub-themes: (a) the inner part of the cirque bottom, (b) low-lying moraines outside the cirque, (c) climatic terraces, (d) other problems of geomorphologic identification. The other theme is a problem of correlation between glacial geomorphology or geology and climatology. It is further divided into three sub-themes, that is, (e) connection between snowbanks and glaciers, and snowlines, (f) climatology of the Ice Age, (g) stages or sub-stages of the Ice Age.
Very important as they are, studies on identification of the glacial features are considerably difficult in some cases, because Japan lacks an existing glacier and only glaciated landforms are found in the upper part of high mountains. Recently, however, more and more students have an interest in the problems of glacial features or the Quaternary in Japan, and much work has been done in these fields of study. They include geomorphological field work around high mountain ridges, observations of the past or present peri-glacial phenomena, researches on accumulation terraces or valley fills and analyses of deep core-samples of lake deposits. Lake Biwa, the Japan's largest lake, and Lake Kizaki located on the piedmont of the Japanese Alps are the lakes under intensive study, providing an accumulative set of materials.
Correlation between glacial cirques or moraines and accumulation terraces or valley fills should be studied exactly, and it must be further extended so as to make it possible to correlate them with basin fills or lake deposits that have been precisely analyzed to assure chronology and climatic changes in the Quaternary Age.
A snow line was discussed from both sides of paleoclimatology and water balance. The glacial formation in the Ice Age in Japan was treated from the view-point of glaciology or science of snow and ice. Such a treatment of the glacial formation was a first trial for the meeting of the Association of Japanese Geographers.
