화강암 거력퇴적물에 관한 연구 - 경남 삼랑진 만어산 일대의 경우 -

Abstract

There are two remarkable granite boulder landforms of the Man-O San in Samrang-jin of the southern part of the Korean penisula. These landscapes could be granite boulderstreams block fields anywhere on the world. These could be interpreted as stripped weathering fronts. The boulder fields consists of large angular or core stones of the late Cretaceous granite granodiorite which are in average 1~2 meters long. I assume these cases are associated with nearby deposits of altered rock (grus) in which core stones etc. survive. The importance of biotite-alteration in granite disintegration may be hydration along cleavages, joints, grounwater through fault line. All features of boulder (block) formation are best explained by incision of an erosion surface and result from weathering by chemical, physical agencies in the sub-soil region, where moisture is retained for lengthy periods. Curved joint planes are considered to be due to surface agencies acting on the already rounded granite boulders. Angular form is similar to that of Dartmoor granite tors, but is not necessarily an indicator of frost action. These cases do not seem to be associated with large of blockfield material which also suggest that frost acton may not have been important. This, too, need not be of periglacial origin although the acclerated erosion and retreat of the hillslope to reveal it may have been.