The related study between the drainage development and geologic structure in Chuhuangkeng Anticline area

• Main Authors: Min-Lam Lan, 藍敏男
• Other Authors: Rong-kuan Yang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/08663718066124968905

碩士 === 國立中央大學 === 應用地質研究所 === 92 === The main purpose of the study is to confer the relationship between the drainage development and geologic structure in Chuhuangkeng Anticline Area. The conformation of the drainage and geologic structure serves as a basis in discussing the drainage development as affected and related to the local geologic conditions. The purpose of the drainage analysis is to survey the relationship between the characteristics of surface drainage and time factor. Numerical analysis on river valley is used to study the stream orders, while spatial analysis on drainage pattern is to realize both the surficial and longitudinal distributions of the drainage systems in the study area. Drainage density analysis is also done to serve as the assisted data in interpretation. And besides, SL-Index is analyzed in combination with longitudinal spatial analysis to obtain the more accurate knickpoint position. The study results show that the development of drainage pattern is mainly dependent on terrain gradient, geologic structures, rock strata, joint and crack systems. Stream orders are less correlated to rock strata, but they are highly influenced by the terrain gradient. Steep gradients always show lower stream orders, and vice versa. Since most of the different tributary drainage systems in the area bear nearly the same stream order, it is reasonably to infer that they have been developing under the same controlling factors as resulted from the drainage spatial distributions and the climate influence. By judging from the longitudinal stream profiles, most knickpoints in the study area belong to hardrock knickpoints, and are always best fitted to the positions of rock contacts. Knickpoints are distributed in sequential terrace array to reflect frequent crustal uplifts. Drainage density map shows a banded boundary between higher and lower anomaly areas, the belt is right at the place of the active fault line, the east limb of the Chuhuangkeng Anticline may still be in an active folding condition.