埔里盆地的地形面活动构造与地形演育.pdfVIP

1 地理研究 第46期 民國96年5月 Journal of Geographical Research No.46, May 2007 埔里盆地的地形面 、活動構造 與地形演育 Geomorphic Surfaces , Active Structures and Geomorphic Evolution of the Puli Basin 1 2 2 3 楊貴三 * 張瑞津 * 沈淑敏* 石同生 * Guey-San Yang Jui-Chin Chang Su-Min Shen Tung-Sheng Shih Abstract Based on aerial photograph interpretation, field investigation and morphometry, the Quaternary geomorphic surfaces of the Puli Basin have been recognized. Three steps of lateritic terrace (LT), one step of fluvial terrace (FT) and one step of fluvial plain (FP) are correlated mainly according to their relative height. Deformed features in the Puli Basin are characterized by the anti-synclinal forms and lineaments including linear valleys, linear scarps, tilting surfaces, tectonic bulges and range-facing scarplets, with a NNE orientation. They have been identified from LT1 to LT3 surfaces but not from the younger surfaces (FT and FP). Among them, surface Tapinding (LT1) in the northern basin tilts to S-SE and surface Waitaping (LT1) in the southern basin flexes to east. Based on the relationship between active structures and geomorphic surfaces, the evolution of the Puli Basin since late Pleistocene is interpreted as follows: (1) According to the imbrication of gravel layers, the Peikang River flowed southwardly into the Puli Basin while the Nankang River and the Mei River drained westerly into the basin, and the Tapinding, Waitapin and Meihsi alluvial fans were formed around basi