Abstract
An evolutionary model of scarp slopes has been constructed for the Lanyang River area of northeastern Taiwan. In this area, younger terraces have higher free-face height/scarp height ratios than older terraces, while the latter have higher debris-slope height/scarp height ratios than the former. The time necessary for a slope to evolve from the free-face to the debris-slope stage is estimated to be less than 1,000 years for the Mimodan fan and the Fubur fan. When a scarp slope forms, its debris-slope angle initially increases exponentially, and then flattens when the debris slope takes over the entire slope. On the other hands, its free-face angle decreases exponentially and then approaches a constant. The slope evolution observed here is close to the non-parallel retreat model. A general slope evolution model can be applied to terrace scarps of subtropical Taiwan as well as scarps in arid western American, in spite of climatic differences. Vegetation cover and weathering conditions on the scarps, however, may vary because of different climatic conditions. These different conditions can result in different rates of degradation and different repose angles. The angles of repose measured in the Lanyang River area for scarps without free-faces may be as large as 45°in contrast to those ranging from 33°to 38°proposed by previous works. The result may improve the resolution of morphological dating in river terraces.
| Original language | English |
|---|---|
| Pages (from-to) | 581-592 |
| Number of pages | 12 |
| Journal | Journal of the Geological Society of China |
| Volume | 41 |
| Issue number | 4 |
| Publication status | Published - 1998 Nov 1 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Geology
Cite this
}
Scarp evolution of fan terraces along the Lanyang River, Taiwan. / Sung, Quocheng; Tsai, Heng; Fu, J. K.; Chyi, S. J.; Lee, P. J.
In: Journal of the Geological Society of China, Vol. 41, No. 4, 01.11.1998, p. 581-592.Research output: Contribution to journal › Article
TY - JOUR
T1 - Scarp evolution of fan terraces along the Lanyang River, Taiwan
AU - Sung, Quocheng
AU - Tsai, Heng
AU - Fu, J. K.
AU - Chyi, S. J.
AU - Lee, P. J.
PY - 1998/11/1
Y1 - 1998/11/1
N2 - An evolutionary model of scarp slopes has been constructed for the Lanyang River area of northeastern Taiwan. In this area, younger terraces have higher free-face height/scarp height ratios than older terraces, while the latter have higher debris-slope height/scarp height ratios than the former. The time necessary for a slope to evolve from the free-face to the debris-slope stage is estimated to be less than 1,000 years for the Mimodan fan and the Fubur fan. When a scarp slope forms, its debris-slope angle initially increases exponentially, and then flattens when the debris slope takes over the entire slope. On the other hands, its free-face angle decreases exponentially and then approaches a constant. The slope evolution observed here is close to the non-parallel retreat model. A general slope evolution model can be applied to terrace scarps of subtropical Taiwan as well as scarps in arid western American, in spite of climatic differences. Vegetation cover and weathering conditions on the scarps, however, may vary because of different climatic conditions. These different conditions can result in different rates of degradation and different repose angles. The angles of repose measured in the Lanyang River area for scarps without free-faces may be as large as 45°in contrast to those ranging from 33°to 38°proposed by previous works. The result may improve the resolution of morphological dating in river terraces.
AB - An evolutionary model of scarp slopes has been constructed for the Lanyang River area of northeastern Taiwan. In this area, younger terraces have higher free-face height/scarp height ratios than older terraces, while the latter have higher debris-slope height/scarp height ratios than the former. The time necessary for a slope to evolve from the free-face to the debris-slope stage is estimated to be less than 1,000 years for the Mimodan fan and the Fubur fan. When a scarp slope forms, its debris-slope angle initially increases exponentially, and then flattens when the debris slope takes over the entire slope. On the other hands, its free-face angle decreases exponentially and then approaches a constant. The slope evolution observed here is close to the non-parallel retreat model. A general slope evolution model can be applied to terrace scarps of subtropical Taiwan as well as scarps in arid western American, in spite of climatic differences. Vegetation cover and weathering conditions on the scarps, however, may vary because of different climatic conditions. These different conditions can result in different rates of degradation and different repose angles. The angles of repose measured in the Lanyang River area for scarps without free-faces may be as large as 45°in contrast to those ranging from 33°to 38°proposed by previous works. The result may improve the resolution of morphological dating in river terraces.
UR - http://www.scopus.com/inward/record.url?scp=0032322855&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032322855&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0032322855
VL - 41
SP - 581
EP - 592
JO - Journal of the Geological Society of China
JF - Journal of the Geological Society of China
SN - 1018-7057
IS - 4
ER -