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Focusing on the neotectonic implications of
morphological dating, thediscussion has lead to the fact
that the far-field-slope-angle of thegeomorphic surfaces
must have an effect on the accuracy of morphologicaldating.
When the far-field-slope-angle increases, the value of
morphologicaldating increases also. Therefore, with future
projects on scarp-like landformsusing morphological dating, one
should consider carefully the effect of thefar-field-slope-
angle. The simulation of terrace scarp with
differentlithology has indicated that the profile has
developed into an asymmetricform, which the significant
effects of lithology will be discussed in futureresearch.
Based on the previous studies of river terraces conducted
on Ta-hsi,Hsin-she, Tsao-tun and Tou-liu hills and the
current research utilizingmorphological dating method on
Chia-i hills, Chao-chou and Lu-yeh fanterraces, and the
mid-section river terraces in Hwa-tung longitudinal valley,we
have drawn the following conclusions: (1) After considering
factors of theeustatic control and the tectonic movement,
we can conclude that thedecreasing in the base level of
erosion would cause the down-cutting of riversto form river
terraces. Therefore, by morphological dating of river terraces,
we can obtain the down-cutting speed of rivers. Further, by
comparing thedown-cutting speed of the rivers with the
eustatic change, the resultindicates that the uplift and the
subsidence of landmass is not affected byany particular
tectonic movement. As a result, climatic change can be the
mainfactor affecting the formation of river terraces.
After comparing pastclimatic data, and we have reason to
postulate that climatic change can be theleading factor in
shaping the development of river terraces in Taiwan in thepast
30,000 years.(2) During the process of morphological dating
research, wehave discovered that morphological dating is very
sensitive to the developmentof geomorphic features (river
terraces). If the result of morphological datingon terraces
indicates longer time span, the terraces is usually developed
overa wide range of space, such as the terraces in Lu-yeh and
Chao-chou.(3) On thediscussion on fault activities, we have
discovered that morphological datingcannot detect the faults
active level if its off-set does not affect theterrace
scarps, such as the earthquake fault line at Mei-san. On the
otherhand, the fault at Chao-chou has stopped its activity at
least 20,000 yearsago according to morphological dating.
In concluding the above research result, morphological dating
can be aworthy supplimentary method to Quarternary dating as
well as establishing thedevelopment of river terraces.
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