| Summary: | 碩士 === 國立成功大學 === 地球科學系碩博士班 === 93 === The purpose of this study is to establish the geological structural evolution model of the Western Foothills fold and thrust belt in Hsinchu-Miaoli area by using sandbox models. The study especially focused on the intersection geometry of different trending structural elements in the study area.
In northwestern Taiwan, two sets of faults, the E-W trending and the NNE-SSW trending, are identified in the Western Foothills. The E-W trending faults are recognized as high angle, right-lateral, strike-slip faults that are originated from the reactivation of pre-existing normal faults which extend from the offshore area to the Western Foothills. The NNE-SSW faults are low angel imbricate thrusts formed by compression induced by arc-continental collision since late Miocene.
The geometric conjunction between the E-W trending high angle faults and the NNE-SSW low angle thrusts can be grouped into four categories: (1) both the NNE-SSW and the E-W trending faults terminated each other, (2) the E-W trending fault terminates on the NNE-SSE trending thrust, (3) the NNE-SSW trending thrust terminate on the E-W trending fault, and (4), the E-W trending strike slip fault and the NNE-SSW trending thrust fault cross each other.
Both the NNE-SSW and the E-W trending faults terminated each other, when these faults initiated at the same time and the experiment stopped after the thrust terminated on the E-W trending fault. The NNE-SSW trending thrust stop on the E-W trending fault, when the applied boundary condition is the same as the above-mentioned condition but the experiment keep going after E-W trending fault terminated on the thrust. If the E-W trending faults formed prior to the formation of the NNE-SSW trending thrust, then the NNE-SSW trending thrust terminated on the E-W trending fault was observed. The E-W trending fault formed before the thrust completely developed and the applied strike slip motion stopped, then the E-W trending strike slip fault and the NNE-SSW trending thrust fault cross each other was observed.
|
|---|
