STRUCTURAL
GEOLOGY AND THRUST BELT ARCHITECTURE OF THE
WESTERN FOOTHILLS OF TAIWAN
Fernando Rodriguez,
Texas A&M University, Geology and Geophysics Department
College Station, TX, 77840
A structural
model of the
central and southern Western Foothills Fold and Thrust Belt (WFFTB) was
constructed from serial balanced
cross
sections
. The WFFTB is composed of four
main thrust sheets with minor splays. On the east, the Tulungwan fault carries a
series of low-grade metamorphosed hinterland imbricates. It evolves from a
basement-cored fold in the north (~ 24°10' N) where Slate Belt and Foothills
rocks are conformable on its western flank. To the south this fault breaks the
back limb of the fold and gains displacement. The next thrust to the west
includes the Schuantung-Fenghuangchan fault system, interpreted as being
underlain by a flat along a Miocene detachment. The next thrust to the west is
the Chukou-Lunhou fault system which is characterized by the presence of a wide
monocline in the central Foothills related to the Chulungpu fault and two wide
synclines in the south, the Yuching and Tinpligling synclines. Modeling of these
two structures shows that both have been uplifted with respect to the regional
level on a wide and flat feature and that the footwall of the Lunhou fault is a
monocline. A geometric solution to this is a low-ramp angle fault-bend-fold with
a detachment at ~13 km. The last thrust system toward the west shows a series of
structures which are closely associated with the Peikang high implying that the
structures are either inversion structures or new thrust faults whose ramps are
located in pre-existing normal faults.
AAPG Search and Discovery Article #90060©2006 AAPG Foundation Grants-in-Aid