永春地域의 河岸段丘硏究 = A Geomorphic Study on River Terraces along the upper South Han-river of Young-chun area

다국어 초록 (Multilingual Abstract)

There are river terraces along the upper course of the South Han river. Typical ones of them are found in the Young chun area. The purpose of this study is to bring out the characterstics and its processes of the river terraces of the Young­chun area.
Ⅰ. The morphological and depositional features of the river terraces of the Young­chun area are as follows：
1）River terraces are located in Young­chun, Neu­ti, and Pam­su­geuri between 170m and 260m in altitude, and all of them could be divided into 3 parts of level. i.e. upper middle and lower levels by the altitude of 180∼190m and 220∼220m, which are steep scarps.
2）Each terrace, in common features, developed consistently along the convexed banks of the meander flow that characterizes the upper South Han river.
3）The upper, middle and lower levels of each terrace, in transverse profile, can be characterized by the following facts： ① The upper level：a. It has a gentle slope about 3∼4 degrees. b. On the terrace plane, there are occasionally bared bedrock surfaces that show considerable relief. c. The thickness of the terrace deposits is 1∼2m, but it varies in different localities. d. The deposits consist of gravels such as boulder, cobble（average size of 8∼10m）and some coarse sand. e. The bedding and the sorting of deposits are almost lacked. f. The roundness of gravel is 0.3∼0.5 ② The middle level：a. It has gentle slope about 2∼3degrees. b. On the terrace plane the bedrocks are bared occasionally, which seem to have been abraded by stream flow. c. The thickness of terrace deposits is 3∼4m but it varies in different localities. d. The deposits of gravels such as cobble pebble（average size of 5∼8㎝）and some medium sand. e. The bedding and the sorting are almost lacked. f. The roundness of gravel is 0.5∼0.6 ③ The lower level：a. It has a very gentle slope, almost flat. b. The terrace deposits of this level are so thick that the bedrock could not be found. c. The thickness of terrace deposits is about 5∼8m. d. The bedding and the sorting of terrace deposits are relatively good. f. The roundness of gravel is 0.6-5∼0.7
Ⅱ. The processes of the river terraces would be revealed as follows：
1）It is considered that the river terraces of this area were formed by the ingrown meandering of the South Han river along the convex bank of the river for the morphological characteristice of the convex bank of South Han river present asymmetrical features.
2）It is clear that the river terraces of this area were produced by the strem flow, which has different stream regime from the present South Han river；in other words, they were produced by the ephemeral stream erosion, because the morphological and depositional facts, revealed the severe intermittent flood state of the river.
Ⅲ. The conclusion of this study are as. follows：
1）The river terrace of the Young­chun area is a kind of Slip­off slope terrace produced by the ingrowned meandering of the South Han river.
2）The stream flow which formed the terrace was the ephemeral one and the present South Han river was derived from it. It may be inferred that the river terraces are the climatic terrace formed under the more arid climatic condition
3）The above facts suggest, strognly, that terraces of this area were produced in accordance with the of erosion base level.

목차 (Table of Contents)

• 一. 緖言
• 1. 硏究目的
• 2. 硏究地域의 槪觀
• 3. 硏究方法
• 二. 本論
• 1. 地形分析
• 2. 堆積物分析과 基盤岩面觀察
• （1）露頭觀察
• （2）堆積物의 粒度分析
• 3. 綜合考察
• 三. 結論