Late Quaternary Equilibrium Line Altitude in the Kiso Mountain Range, Central Japan

抄録

Geomorphological equilibrium line altitude (ELA_g), as defined by steady-state equilibrium line altitude estimated based on geomorphological method, has been used to reconstruct Last Glacial palaeoclimate. However, the ELA_g is influenced not only by temperature, but also by other factors. This paper discusses factors affecting Last Glacial ELA_g in the Kiso mountain range, central Japan. The weathering-rind thickness of gravel was used for dating moraines. The dating results have shown that glaciers advanced at the Last Glacial Maximum and the Younger Dryas stages. The ELA_g for each stage was reconstructed based on the Accumulation-Area-Ratio method (AAR=0.6). The results indicate that the ELA_g of each reconstructed glacier was affected not only by temperature but also by the altitude of mountain ridges. Although some previous studies have reconstructed palaeoclimate based on the ELA_g, the results of the present study cast doubt on such reconstruction. For better reconstruction, the effects of temperature on the ELA_g should be separated from those of topographic factors.