草嶺大崩山之地質與地形演變

Geomorphological Evolution and Geology of the Tsaoling Rockslide

李錫堤(Chyi-Tyi Lee)

《中華水土保持學報》 42卷4期 (2011/12) Pp. 325-335

https://doi.org/10.29417/JCSWC.201112_42(4).0006

摘要

作者近三十年來曾多次深入到草嶺崩塌地的內部及清水溪河床，觀察崩積物及其下部未受擾動岩盤的狀況，並測繪崩山地區比例尺一萬分之一的地質圖，供山崩分析之用。這些觀察、測繪及相關的調查結果，對於歷次大崩山的滑動範圍、滑動面的推定及進一步崩滑可能性的評估頗有幫助。本文回顧前人研究及作者歷年的研究成果，綜合討論草嶺大崩山之原因及其地形演變。草嶺大崩山是典型的天然順向坡滑動，其百餘年來之地形演變說明了順向坡滑動的一部分地形循環。預期草嶺順向坡會繼續發生中大規模的滑動，直至完整地露出大窩砂岩頂部而形成「蓋岩」，完成一個完整的地形侵蝕循環。這種快速的順向坡地形侵蝕循環，可能是活動造山帶中的一種重要的地形演變現象。

關鍵字

順向坡 ； 山崩 ； 地形循環 ； 地形演變

並列摘要

The author travelled deeply into the Tsaoling Rockslide area and the Chingshui riverbed several times in the recent three decades, observing the landslide deposits and undisturbed rocks underneath, and mapped the geology on a scale of 1 to 10 thousand. These investigations, observations, mapping and testing results have provided plenty of data for recognition of the extent of the sliding at each different stages, the presumption of sliding planes, and evaluation of future slides. This study reviews previous studies and the results of the author's research over the years, and also provides comprehensive discussion of the cause of the slides and landscape evolution of the Tsaoling dip-slope. The Tsaoling Rockslide is a typical natural dip-slope slide due to river under-cutting. The landscape evolution throughout the history of more than a century shows a part of the terrain cycle of erosion. The Tsaoling dip-slope is expected to continue to occur through moderate to large scaled slides, until a firm ”caprock”, a top layer of the Tawo Sandstone, has formed, and thereby a terrain cycle of erosion for the dip-slope is completed. This kind of rapid terrain erosion cycle may be an important geomorphological feature in an active orogenic mountain.

並列關鍵字

Dip-slope ； landslide ； cycle of erosion ； geomorphological evolution