徐美玲2006-07-252018-06-282006-07-252018-06-281999http://ntur.lib.ntu.edu.tw//handle/246246/11353階地邊坡演育過程的研究，有助於釐 清邊坡形態與邊坡地形作用之關係，實乃 利用邊坡形態進行階地定年的基礎。本研 究以宜蘭縣蘭陽溪中游夫布爾階地鄰主流 沿岸階崖為研究對象，根據邊坡坡面的組 成物質、坡度、沖蝕狀況以及植生情形將 階地邊坡劃分成均質的坡單元，並詳細記 錄相關的組成、形貌和地形作用情況，再 將所蒐集到的資料根據此等因子的特徵進 行分類，然後進行統計分析，歸納出各類 坡單元與環境因子之間的關係。結果發 現，邊坡組成物質對坡度的影響最具顯著 性。野外的觀測發現，階地的自由崖面是 以落石或淺層滑落為改變邊坡形態的主要 地形作用，邊坡採間斷後退的方式，其坡 度並未與演育時間有明確的相關。階崖下 方的崩積坡則會受到蠕移、雨水濺蝕、土 壤沖蝕等作用的影響，而逐漸減緩坡度， 但是一旦上方自由崖面發生崩塌，則會因 為堆積物質的增添而再度增高坡度，因此 以目前階崖邊坡尚未被崩積坡完全覆蓋的 階段而言，崩積坡的坡度也不會隨著時間 穩定變緩，此時以擴散模式為基礎所發展 的邊坡演育模式，顯然不適於用來推估邊 坡的演育時間。Research on terrace slope evolution helps to clarify the relationship between slope form and geomorphological processes, and is essential to geomorphological dating of terraces. The Fu-Bu-Er terrace located in the Lang-Yang -Chi is chosen as the study site. The terrace slopes are delineated into homogeneous units, and the geology, surfacial gradient, erosion, vegetation conditions of each unit are carefully observed and recorded. The collected data are then classified according to material type, morphological characteristics and working processes. Further statistical analyses are performed in order to postulate the relationships between slope form and environmental factors. The author concludes that the geology of terrace slopes is the most significant factor in controlling slope gradient. Field observations reveal that the free scarp slope retreats by periodic rockfalls and debris slumps, thus, no definite relationship exists between slope gradient and the age of the slope. Debris slopes beneath free scarp faces are subjected to creeping, rain splash, and soil erosion, and then start to reduce their gradients. However, when the free scarp face above any debris slope fails, new material adds to increase the height and gradient of the debris slope. As long as the free scarp face exists, the gradient of the debris slope will fluctuate, but will not diminish with time. As a result, the diffusionbased slope evolution model is not apt to simulate slope change or to estimate the age of the slope. .application/pdf31312 bytesapplication/pdfzh-TW國立臺灣大學地理環境資源學系暨研究所邊坡演育階地定年自由崖面崩積坡擴散模式slope evolutionterrace datingfree scarp facedebris slopediffusion modelreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/11353/1/882116M002016.pdf