A comparative geomorphological study based upon the environmental dating method of erosional forms on Karst region in Japan.

本研究的目的是弄清温带和亚热带岩溶侵蚀形态的区域差异.以秋吉台和平台石灰岩高原为例，说明了其属于温带岩溶区，具有多林岩溶的特征。然而，在琉球群岛，作为亚热带岩溶区的一个例子，有下降漏斗地，锥岩溶区和岩溶干谷。这些喀斯特地貌在日本非常重要。2.在我们对Karrenfeld地貌的比较研究中，几乎所有由A.Bobli、M.M.Sweeting、J.N.Jennings、D.福特和P.威廉姆斯分类的岩溶类型都出现在秋吉台岩溶地和琉球群岛上。在平台高原石灰岩露头上有时发育曲流溶孔和石灰岩铺面，但在琉球岩溶区则不发育。岩溶地貌为气候地貌学提供了许多很好的范例。碳酸盐洞穴沉积物的分析为石灰岩地区的气候地貌学提供了一个有趣的领域。洞穴沉积物由许多层组成，这被称为生长环。许多洞穴沉积物环已被ESR测年和LLMZA分析。年轮的形成和每层年轮的体积（或厚度）指示晚第四纪气候变化的影响。同样，各层在各时期的生长速率之间的关系反映了岩溶地貌的相对剥蚀速率，这一研究结果为探讨第四纪岩溶地貌演化与气候变化的关系提供了新的途径。这一新的方法似乎是揭示全球石灰岩地区第四纪气候变化的有用方法。

The purpose of this research is to make clear regional differences of karstic erosional forms on the temperate region and the subtropical region.1. On the Akiyoshidai and Hiraodai limestone plateaus, as an example for the temperatic karst region, they are characteristic of Doline karst. However, in the Ryukyu islands, as an example for the subtropical karst region, there are found downed doline lands, cone karst areas and karstic dry valleys. These karst land forms are very important in Japan.2. On our comparative geomorphological study of Karrenfeld, almost all types of karren classified already by A.Bobli, M.M.Sweeting, J.N.Jennings, D.Ford and P.Williams are found on the Akiyoshidai karstland and the Ryukyu islands. Sometimes meander karren and Iimestone pavement develop upon limestone outcrops in the Hiraodai plateau, but they are absence on the Ryukyu karst areas.3. Karst landforms have presented many good examples for climatic geomorphology Analysis of carbonate speleothems offers an interesting field for climatic geo morphology in limestone regions. The speleothem consists of numerous layers-, this is called Growth rings. Many speleothem rings have been analyzed by ESR Dating and LLMZA. The formation of growth rings and the volume ( or thickness ) of each layer of growth rings are indicative of an influence of Late Quaternary climatic changes. Similarly, the relationship between the growth rates of each layer in each period show the relative denudation rate of karst terrain.The results of this study show a new approach to the investigation into the relationships between the evolution or karst landforms and the climatic changes during Quaternary period. This new approach seems to be useful method of revealing the Quaternary climatic changes in limestone areas worldwide.