Geologic Structure
The Neogene rocks in the Coastal Range were folded into a series of NNE- trending anticlines and synclines
with the Tuluanshan Formation forming the core of most major folds. The folds have been cut by several
thrust faults, which dip mainly to the east (Fig. 8). No metamorphic effect has been noted in this eastern
fold-and-thrust belt. Because massive agglomerate is the dominant lithology, the imbricate thrust fault
system in this tectonic belt is not as clearly defined and well- developed as that in the western foothills,
where well-bedded stratified rocks are dominant. A series of structure cross sections of the Coastal Range
from north to south is shown in Fig. 8. Most of the thrust faulting in the Coastal Range appears to be
younger than early Pleistocene (Chi et al., 1981).
Figure 8. Schematic structure cross sections of the Coastal Range (Angelier and Barrier, 1986)
A more complete analysis and elucidation of the tectonic development of the Coastal Range is not yet possible
because only limited areas have been studied in detail. More extensive petrotectonic, stratigraphic,
structural, and other studies over the entire mountain range are essential to clarify the overall tectonic
evolution of eastern Taiwan.