Glacial landforms and the height of pleistocene orographic snowline around Mt. Harinoki and Mt. Renge, Northern Japanese Alps

Abstract

The authors investigeted in detail the glacial landforms in the area around Mt. Harinoki (2, 820.6m) and Mt. Renge (2, 798.7m), through field surveys and aerophoto-interpretation. Judging from the location of terminal moraines, outwash terraces, trough edges, glacial polishes, and the difference of dissection of glacial landforms, four glacial stades were recognized. They were named, from the older to the younger, Harinoki I, II, III and IV stades respectively. The Harinoki I stade corresponds to a maximum glacial extent in this area, when several glaciers extended to about 1, 600 or 1, 700m a. s. l.
The distribution of glaciers in each stade indicateds that the glacier extended more on the northern slope than on the southern slone in every stade. The mean altitude of orographic snowline on both slopes was estimated by using the Brückner's method. It was higher on the northern slope than on the southern slope in the I and II stades, while it was lower on the former than the latter in the III and IV stades.
By comparing the orographic snowline of each stade in this area to that in the Yari-Hotaka Mountain Range (Ito, 1982), the difference of air temperature in two areas was estimated as follows; The mean annual air temperature in this area is lower than in the Yari-Hotaka Moutain Range of about 0.4°C in the I stale (the Takitani stade), 0.5°C in the II stade (the Yaridaira stade), 0.9°C in the III stade (the Hidazawa stade I), and 1.0°C in the IV stale (the Hidazawa stade II) respectively. The value in the younger stade, for in the IV stade, is similar to the value at present (1.2°C).