臺灣山脈抬升與河流侵蝕之關聯性研究－以丹大溪地區為例

Study on the Relationship between Tectonic Uplift and Stream Erosion - as an Example for the Danta River

柯明淳(Ming Chun Ke) ； 羅偉(Wei Lo) ； 吳明諭(Ming-Yu Wu) ； 李文正(Wen-Jeng Lee)

《臺灣鑛業》 72卷2期 (2020/06) Pp. 1-10

摘要

造山運動造成臺灣島每年有4毫米的抬升速率，而因臺灣所處之地理位置，在氣候條件影響下加速了風化、侵蝕等外營力作用，使得臺灣島各地平均每年也有3至6毫米的侵蝕速率。以往大部分地質學者對臺灣侵蝕速率的研究多從麓山帶或海岸山脈的定年資料、輸砂量與地形計測方法著手，卻少人研究臺灣中央山脈高山地區的抬升作用與侵蝕作用。然而侵蝕速率高低往往可以僅代表當時的環境條件，並無法反映長期抬升與侵蝕間之變化。本研究嘗試利用鋯石的核飛跡定年資料，以岩石剝蝕速率與野外調查工作來了解長時間尺度的地體抬升與侵蝕速率之關聯性。根據結果，丹大溪從上游（2.0mm/yr）至下游（6.0mm/yr），其剝蝕速率有越來越快的趨勢，而崩塌熱點區域多落於剝蝕速率等值線較為平緩之區域。

關鍵字

崩塌 ； 剝蝕速率 ； 山脈抬升

並列摘要

The rate of tectonic uplift in Taiwan is 4mm in per year. By the geographical location of Taiwan, weathering, erosion and other exogenic process have been strengthened with climatic conditions. The average erosion rate across Taiwan Island was 3 to 6 mm per year. In past time many researches about erosion rate of Taiwan were by using data, which like age dating, sediment discharge and topographic measurement, of the Western Foothills or the Coastal Range. However, the erosion rate could be represented a result of the environmental conditions on that time. Changes between long-term uplift and erosion were unable to reflect by using those results of erosion rate. In this study, the relationship between tectonic uplift and stream erosion for long-time scale was known by using denudation rate from fission tracks of zircons and the results of field survey. According to the results, the denudation rate in the Danta River has been increasing trend from upstream (2.0mm / yr) to downstream (6.0mm / yr) and the hot spots of landslide events were almost in relatively flat areas of the denudation rate contours.

並列關鍵字

Landslide ； Denudation rate ； Tectonic uplift