마성분지의 지형생성작용

다국어 초록 (Multilingual Abstract)

There is a limestone basin surrounded by the mountains consisted of Paleozoic sedimentary and metamorphic rocks in the Masung, Munkyung city, Kyungsangpook do. The purpose of this paper is to elucidate the geomorphic processes of the gentle hillslopes in the marginal piedmont of Masung basin. To do so, I analyzed deposits over hillslopes and the relation ship between the distance from the divide and the height(above sea level) at the longitudinal profile of the hillslope, and considered interrelation between the distributions of the gentle hillslopes(less than 230m) and lithology. Geomorphic processes of Masung basin are as follow: ① The depth of deposits over hillslope increases toward downstream of the hillslope. Most gravels within deposits, whose lithology is limestone, are those eroded at the boundary (overthrust fault zone) between the back-mountain and the hillslope. Deposits at the outward margin of hillslope is well sorted, and moderately imbricated. ② Hillslope at the margin of the basin(160-230m asl) is formed by the action of `the flow with channel`. At the boundary between the soft rock(limestone: basin floor) and hard rock(sedimentary and metamorphic rock: back-mountain), the relatively weak limestone is eroded to fresh bedrock by the subsequent action of the overland flow, and therefore discontinuity in slope appeared. ③ After hilislopes were formed, sediments(boulders and fine material) produced during dissection in back-mountain buried deposits over hillslope. In conclusion, geomorphic processes of Masung basin is `differential erosion due to differentiation of lithological hardness` having suggested as geomorphic processes of granitic basin. However it is not `removal of weathering material due to sheetflow` but `erosion due to the overland flow with channel`