12:00 PM - 12:15 PM
[SIT29-11] The Chimei submarine canyon and fan: A record of Taiwan arc-continent collision
Keywords:sedimentary record of tectonics, submarine canyon, submarine fan, Taiwan arc-continent collision , seismic reflection profile
The Chimei fan was deposited above a seismic sequence boundary that separates more transparent and chaotic middle and upper sequences (fan sequences) from the underlying continuous and concordant lower (pre-fan) sequence. The seismic facies in lower sequence shows continuous and parallel seismic reflections that onlap upon the Huatung Basin oceanic crust, which we interpreted it to be original deep sea sediments of the Huatung Basin. Most lower-fan seismic characteristics are shown in the middle sequence and upper-fan characteristics are shown in upper sequence. Based on their seismic facies characteristics, we interpret the middle and upper sequences to be composed of orogenic sediments from Taiwan arc-continent collision. The different seismic facies within each sequence of the Chimei fan record a progression of Taiwan orogeny: (1) During initial arc-continent collision, sediments were delivered from the Central Range to the Huatung Basin and initial Chimei submarine fan was formed. (2) After the Luzon arc has uplifted above sea-level, the Chimei submarine canyon and deep-sea valley was formed along the topographic low of the Luzon arc, northern part of the Chimei fan has been eroded away, and only southern part of fan behind topographic high of arc has been preserved. It is anticipated that future sampling of the uplifted strata of the Chimei submarine canyon, Chimei fan complex and pre-fan sequences through a variety of means, including coring and ocean drilling will provide much insight into the dynamics of collisional mountain belts.