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

日本列岛岩石冰川研究及其古环境意义

基本信息

批准号：
09680179
负责人：
IWATA Shuji
金额：
$ 2.43万
依托单位：
Tokyo Metropolitan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

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.

1.本次研究通过航片判读，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。大部分的岩石冰川位于日本中部的希达山脉，还有一些位于日本中部的赤石山脉和北海道的希达山脉和大雪火山块。该清单包括22幅利用航空立体测图编制的典型岩石冰川大比例尺等值线图。除了雪深测量和地电测量之外，还通过间接地球物理探测来研究岩石冰川的内部结构，例如全年监测地面温度。1999年10月，在仓之助岩冰川的表层碎屑层之下发现了一层冻结层。在日本以外的尼泊尔和不丹喜马拉雅山、瑞士阿尔卑斯山和南极洲，对活跃的岩冰川进行了实地研究。冰缘模型将缓慢的岩冰川运动归因于冻土蠕变。日本高山的岩冰川分为以下三种类型和时期：（1）化石岩冰川形成于约1万年前的晚冰期;（2）化石岩冰川形成于几百万年前至几百年前的新冰期和小冰期;（3）非活动岩冰川形成于几百年前至150年前的小冰期。在上述寒冷期，山地冻土带一定很宽，足以形成大量的岩石冰川。随后的永久冻土融化会使这些岩石冰川融化，其中一些可能被误解为冰碛脊或Protalus壁垒。