MORPHOLOGICAL AND SEISMIC CHARACTERISTICS OF THE KAOPING SUBMARINE-CANYON

SeaMARC II side-scan sonar images and swath bathymetry plus 6-channel seismic reflection profiles reveal details of major canyons in the submarine portion of the Taiwan collision belt. The Kaoping Submarine Canyon is the largest of these, extending over 240 km from the mouth of the Kaoping River across the accretionary wedge to the Manila Trench. Morphological features and structural settings vary along the course of the Kaoping Submarine Canyon, defining three sections. The first section extends southwest from the mouth of the Kaoping River, cutting across the shelf and upper slope roughly perpendicular to local bathymetric contours, to about 22-degrees-03'N, where the canyon turns sharply southeast. From this point, the second section of the canyon follows the trace of a major thrust fault, paralleling local structure to 21-degrees-35'N, at which point the canyon turns southwest again. Over the third section the canyon meanders, cutting through low-relief fault-bend anticlines and distributing orogenic sediments in intervening slope basins, to where it joins the Manila Trench. Seismic profiles reveal that this canyon, which forms a major sediment conduit between the Taiwan mountain belt and the Manila Trench, has a complicated evolutionary history, and that its development has been controlled strongly by accretionary structural processes.