新店溪河階之地形學研究

Abstract

River terraces including six lateritic surfaces (LH、LT1-LT5) and three non-Iateritic surfaces (FT1-FT3) have been recognized along Hsin-tien River. Most of lateritic surfaces distributed concentrately at Ping-lin, Shen-chang-Pan and Hsin-tien. Comparatively speaking, surfaces LT4, LT5 and FT2 distributed more widely and continuously than the others. Under the effect of tilting, the channel tended to shift from south to north and became sinuos. Sinuosity increased to the maximum in the LT4 stage that imp1ied the river had a significant lateral erosion in relatively stable stage. FT terraces have been formed under the controlling effect eustatic fluctuation and subsidence of Taipei Basin. The meander cut occurred during the lowering base level stage (FT1-FT2). Referring the results of climatic and eustatic fluctuation, the LT5 and three FT surfaces have been formed respectively in high sea level around 40000, 10000, 6000 and 3000 years before present.