Sea level and climatic controls on turbidite occurrence for the past 26 kyr on the flank of the Gaoping Canyon off SW Taiwan

Abstract

Submarine canyons are major conduits for delivery of sediments originating from the continental margin into the deep sea. Here we analyze the effects of changing sea levels and climate (e.g. sediment supply) on the frequency of turbidites over the last 26kyr. Our study is based on high resolution age controls for turbidites in core MD178-10-3291 from a water depth of 2070m on the flank of the Gaoping Canyon offshore in SW Taiwan. Unlike most other submarine canyons worldwide, the head of the Gaoping Canyon has remained connected to the river mouth during the recent flooding of the continental shelf. Our results reveal that turbidity currents are less frequent during periods of sea-level lowstand. In contrast, turbidity currents have been more frequent since ~12kyrBP, during the final stage of rising sea level and sea-level highstands. This may be the result of increased terrestrial sediment delivery due to enhanced rainfall intensity. Moreover, comparing to other source-to-sink systems, the turbidite occurrence in the flank of Gaoping Canyon through the last glacial cycle might have been more strongly influenced by climatic changes due to short sediment storage/response time.