Deepwater Canyons Reworked by Bottom Currents： Sedimentary Evolution and Genetic Model

• Published in: Journal of earth science (Wuhan, China) Vol. 23; no. 5; pp. 731 - 743
• Main Author: 吕彩丽 姚永坚 龚月华 吴时国 李学杰
• Format: Journal Article
• Language: English
• Published: China University of Geosciences China University of Geosciences 01.10.2012; Springer Nature B.V
• Subjects: Architecture; Biogeosciences; Canyons; Deepwater exploration & production; Deposition; Dynamics; Earth and Environmental Science; Earth science; Earth Sciences; Evolution; Evolutionary biology; Genetics; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Migration; Sedimentary geology; Seismic phenomena; Turbidity; 峡谷; 底流; 横向迁移; 沉积; 深海; 演化模型; 珠江口盆地; 返工; South China Sea; turbidity current; deepwater canyon-channel; lateral migration; bottom current
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-012-0280-3

Based on multi-beam bathymetric data and 2D high-resolution, multi-channel seismic prof＇des, combing ODPl148 drilling data, the morphology, internal sedimentary architecture, and evo-lution pattern of 17 deepwater canyons from the Middle Miocene to present are documented in the northern Baiyun （白云） sag （BS）, Pearl River Mouth basin （PRMB）, and northern South China Sea （SCS）. There exist six seismic architectural elements in these canyons, including basal erosive surfaces （BES）, thalweg deposits （TD）, lateral migration packages （LMP）, mass transport deposits （MTD）, can- yon margin deposits （CMD）, and drape deposits （DD）. According to the stratigraphical ages and geo-metrical features of these canyons, their formation and evolution processes are divided into three stages： （1） Middle Miocene scouring-filling, （2） Late Miocene lateral migration, and （3） Pliocene-Quaternary vertical overlay. An auto-cyclic progressive process of eroding and filling by turbidity currents results in the scouring-filling and vertical overlay; bottom currents are responsible for the remarkable asym-metry between the two flanks of canyons; and faults are inherent dynamic forces triggering these can yons. It is inferred that these canyons are caused by the double effects of turbidity and bottom currents under the control of faults as inherent dynamic forces.