Geomorphic response to growing fault-related folds:example from the foothills of central Taiwan
Wen-Jun Wang
Abstract
¡@The active Quaternary deformation of the anticline area in the foreland belt of western Taiwan is characterized by a thrust-and-fold zone. The Tiehchen, Tatu and Pakua ridge belt is a fault-related anticline system located in the hanging wall of the Changhua fault along the western thrust front of the foothills. We concentrate particularly on the geomorphological indicators left by active tectonics in the central foothills of Taiwan. We performing quantitative morphometric analysis and determinerelative age of fault-related anticlines by topography, drainage pattern, and structural data.
¡@Geomorphic systems are analysed with intent to detect the various responses of landforms and drainage pattern to late Quaternary deformation. Topography and drainage basin register uplift and are valuable tools to discriminate lateral propagation of an active frontal fold. Geomorphic field evidence and quantitative morphometric parameters are used to define the evolution of the rising anticline ridges and to infer tectonism style along an active front. Geometry of alluvial fans, formed along the frontal side of the anticlines, and weathered terrace deposits provide relevant information on neotectonics. Knowledge concerning these younger anticline ridges, makes this area a good example of an actively forming mountain front. We discuss in detail the origin of N045¢X, N095 and N120¢X trending oblique fault scarps which delimitate numerous fault blocks. The fault scarp morphology is characterized by imbricate talus facets. Steeper topography accompanied by breaks in the slope along some transverse profiles, seems to correspond to the traces of successive uplifts.
¡@But compare with geophysical data, reverse thrust faults: Tiechenshan fault, east Tachia fault, and Hsianshan fault do not exist.
Reference
Bernard Delcaillau, 2001. Geomorphic response to growing fault-related folds: example from the foothills of central Taiwan.Geodinamica Acta, 14, 265¡V287.
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