동강유역 하안단구와 곡류절단의 지형 발달 = Geomorphic Development of River Terrace and Meander Cut-off in the Donggang

다국어 초록 (Multilingual Abstract)

The Donggang is the main tributary of the Namhangang, and being incised meander with eight levelled river terraces and five meander cut-off. From the interpretations of aerial photographs, topographical map, and the field survey of these landforms, the main results are summarized as follows: 1) Eight levelled river-terraces are distributed in the Donggang and they are classified as the DH I, DH II, DH III, DH IV, DH V, DM, DL I, DL II surfaces in descending order. 2) It is estimated that DH surfaces were ,made in the Mindel Glacial age or over, DM surface the Riss Glacial age, DL. I the early Wu¨rm, DL II the late Wu¨rm Glacial age. 3) Ground uplift was estimated to be done after DH I surface was made when we consider the characteristics of wide river-terrace and pained pattern distribution 4) Meander cut-off pattern in the Donggang is classified into two modes: meander neck cut-off and stream capture. Meander cut-off in the main stream is caused by geologic structure which restricts the lower shifting of meander belt. Meander cut-off in the tributary were caused by capturing the tributary channel and also by the main stream restricting the lower shifting of tributary channel 5) Doline could be a character in classifying river-terraces. There are four types; ① river-terrace with no doline, ② river-terrace with small-sized doline which only can be identifiable by field survey, ③ river-terrace with doline whose width covers 10-20% of river-terrace that can be interpreted by the aerial photographs, ④ river-terrace with compound doline or doline whose width covers mare than 30% of river-terrace. The examination of the geomorphic feature of dolines and various geomorphic feature of river-terraces leads to the following estimations: $quot;①$quot; is estimated to belong to the lower river-terrace, $quot;②$quot; is estimated to belong to the middle river-terrace, and $quot;③ and ④$quot; are estimated to belong to the higher river-terrace.