Study on rock glaciers in the Japanese Islands and their palaeoenvironmental significance

1.通过对本研究的航空照片解译，发现并绘制了30多个岩石冰川，并完成了岩石冰川的初步清查。大部分岩石冰川位于日本中部的平田山，少数位于日本中部的赤石山，以及北海道的平田山和大泽火山地块。该清单包含22张大比例尺的典型岩石冰川等值线图，这些地图是利用航空照片的立体测绘编制的。除了雪深测量和地电测量外，还通过间接地球物理探测，例如全年监测地面温度，来探讨岩石冰川的内部结构。1999年10月，库拉诺苏克岩石冰川在地表碎屑层下观察到一层冻结层。在日本以外的尼泊尔和不丹喜马拉雅山脉、瑞士阿尔卑斯山和南极洲对活跃的岩石冰川进行了实地研究。冰缘模型将岩石冰川缓慢移动的原因归因于冻土蠕动。日本高山的岩石冰川可分为以下三种类型和时期：(1)形成于约10000年前的晚期冰期的岩石冰川，(2)形成于几百万年至几百年前的新冰期和小冰期的化石岩石冰川，(3)形成于几百年前至150年前小冰期的不活跃的岩石冰川。在上述寒冷时期，山脉永久冻土带一定足够宽，形成了许多岩石冰川。随后的永久冻土融化会使这些岩石冰川变成化石，其中一些可能被误解为冰河脊或长城墙。

1. More than 30 rock glaciers were found and mapped by aerial photo-interpretation of the present study, and a preliminary inventory of rock glaciers was completed. Most of the rock glaciers are located in the Hida Mountains, central Japan, and a few in the Akaishi Mountains, central Japan, and the Hida Mountains and Taisetsu Volcanic Massif, Hokkaido.2. The inventory contains 22 large-scale contour maps of typical rock glaciers compiled by using stereo-plotting of air photographs.3. The internal structures of rock glaciers has been approached by indirect geophysical soundings such as the year-round monitoring of ground temperature besides the snow-depth measurements and geoelectrical measurements. In Kuranosuke Rock Glacier a frozen layer was observed beneath the surface debris layer in October, 1999.Field researches of active rock glaciers were carried out outside Japan, in the Nepal and Bhutan Himalayas, the Swiss Alps, and Antarctica.The periglacial model attributes a slow rock glacier movement to permafrost creep.Rock glaciers in the Japanese high mountains were classified into the following three types and periods: (1) Fossil rock glaciers formed during the Late Glacial period around 10000 years ago, (2) Fossil rock glaciers formed during the Neoglacial and Little Ice Age periods between a few million years and a few hundred years ago, (3) Inactive rock glaciers formed during the Little Ice Age between a few hundred years ago and 150 years ago. The mountain permafrost belt must have been wide enough to form a number of rock glaciers during the above mentioned cold periods. Subsequent permafrost melting would have fossilized these rock glaciers, some of which may have been misinterpreted as moraine ridges or protalus ramparts.