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

1. 本研究通过航拍解译发现并绘制了30多个岩石冰川，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飞驒山脉，少数位于日本中部的明石山脉，以及北海道的飞驒山脉和大越火山群。该目录包含22张典型岩石冰川的大比例尺等高线地图，这些地图是利用航空照片的立体绘图编制的。除了雪深测量和地电测量外，还通过全年地温监测等间接地球物理探测方法研究了岩石冰川的内部结构。1999年10月，在Kuranosuke岩石冰川表面碎屑层下观测到一层冻结层。在日本以外的地区、尼泊尔和不丹的喜马拉雅山、瑞士阿尔卑斯山和南极洲进行了活动岩石冰川的实地研究。冰缘模式将缓慢的岩石冰川运动归因于永久冻土的蠕变。日本高山岩冰川可分为3种类型和时期：(1)形成于1万年前左右的晚冰期化石岩冰川；(2)形成于几百万年至几百年前的新冰期和小冰期化石岩冰川；(3)形成于几百年至150年前的小冰期非活动岩冰川。在上述寒冷时期，山地永久冻土带一定足够宽，足以形成许多岩石冰川。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碛垄或protalus壁垒。

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.