Abstract
The Chimei Canyon is a large, uplifting wedge‐top submarine canyon offshore eastern Taiwan that has delivered sediment since ~1–2 Ma from the rapidly eroding Taiwan orogen to the Chimei Fan in the Huatung Basin, east of the colliding Luzon Arc. In this study, we document the depositional record of the Taiwan arc‐continent collision on the adjacent oceanic Philippine Sea Plate using multichannel seismic reflection data together with high‐resolution bathymetry data to study the morphology, seismic sequences, and structures of the Chimei Canyon‐Fan system. The sedimentary strata are separated into three seismic sequences. The lowest sequence overlies oceanic crust, showing Cenozoic‐Cretaceous pelagic seismic facies that we interpret as pre‐collisional, whereas the middle and upper sequences are syn‐collisional. We propose a model for the development of the Chimei Canyon‐Fan in which the middle sequence first developed ~1–2 Ma, while the main depocenter was to the west in the forearc basin, west of the Luzon Arc. The upper sequence records a shift of depocenter after ~1 Ma from the forearc basin to the Chimei Fan east of the Luzon Arc. At the same time, this antecedent paleochannel‐fan system was deformed rapidly (~60 mm/yr; 62 km minimum shortening) by a complex imbricate thrust belt with the emergence of the arc and forearc basin as the west‐vergent Coastal Range thrust belt and the Chimei Canyon incising the active east‐vergent Offshore East Taiwan thrust belt. The thrust belt underlying the wedge‐top Chimei Canyon‐Fan has undergone >19‐km shortening and ~2.6‐km structure uplift.