Periglacial environment in Japan: present and past
Periglacial environment in Japan: present and past
复制标题
日本的冰缘环境：现在和过去
作者：
M. Nogami;T. Fuaze;M. Fukuda
本文介绍了日本冰缘环境的历史和现状，并对有关冰缘环境的研究进行了综述。日本冰缘气候的特点是气温年较差大，冬季积雪多。这使得当地的变化，在出现冰缘过程的山坡附近的波峰。在日本，冰缘研究的主要兴趣是关注上述变化及其原因，即冰缘过程与植被、当地气候特别是积雪及其季节性持续时间、土壤、微地形、基岩性质等的关系。无积雪覆盖时的霜冻深度与累积度日数的增加成正比。在自然条件下，霜的渗透深度不仅受度日的影响，而且受积雪深度的影响，即使在很小的区域内，积雪深度也会发生局部变化。最古老的冻土现象是在北海道低地的约5万年前的地平线上发现的。大约4万年前的内卷超过了活跃的地球丘的大小。最大相位的现象是由En-a浮石的冰楔铸件（约。15，000 abp）。大部分化石特征覆盖着未受干扰的Ta-d浮石（cz. 9，000 abp），但在全新世火山灰层中仍然形成了土丘和垂直的石头。
This review article is intended to introduce periglacial environment present and past in Japan, and to summarize some studies on it. The periglacial climate in Japan is characterized by a wide annual range of air temperature and much snow accumulation in winter. This makes for local variability in appearance of periglacial processes on the mountain slopes near crests. In Japan, the main interest in periglacial studies concerns the above-mentioned variability and its causes, that is, how periglacial processes relate to vegetation, local climate especially snow accumulation and its seasonal duration, soil, micro-relief, properties of bed rock etc.Seasonal soil freezing was measured in lowlands of Hokkaido. Depth of frost penetration without snow cover increases proportionally to the increments of accumulated degree-days. Depth of frost penetration on natural conditions is affected not only by the degree-days but also by the depth of snow cover which differs locally even within a small area.The oldest frozen ground phenomena was recognized in a horizon about 50,000 years old in the lowlands of Hokkaida. Involutions about 40,000 years ago exceeded active earth hummocks in size. And the phenomena reached the maximum phase is represented by icewedge casts of the En-a pumice (ca. 15,000 abp). Most of fossil features are covered with undisturbed Ta-d pumice (cz. 9,000 abp), but earth hummocks and vertical stones have been still formed in the Holocene tephra layers.