Flow processes and sedimentation in unidirectionally migrating deep‐water channels: From a three‐dimensional seismic perspective |
| |
| Authors: | Chenglin Gong Yingmin Wang Ronald J Steel Jeff Peakall Xiaoming Zhao Qiliang Sun |
| |
| Affiliation: | 1. State Key Laboratory of Petroleum Resources and Prospecting (China University of Petroleum, Beijing), Beijing, China;2. Department of Geological Sciences, Jackson School of Geosciences, University of Texas, Austin, TX, USA;3. Ocean College, Zhejiang University, Hangzhou, Zhejiang, China;4. School of Earth and Environment, University of Leeds, Leeds, West Yorkshire, UK;5. School of Geoscience and Technology, Southwest Petroleum University, Sichuan, China;6. Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China |
| |
| Abstract: | Three‐dimensional seismic data were used to infer how bottom currents control unidirectional channel migration. Bottom currents flowing towards the steep bank would deflect the upper part of sediment gravity flows at an orientation of 1° to 11° to the steep bank, yielding a helical flow circulation consisting of a faster near‐surface flow towards the steep bank and a slower basal return flow towards the gentle bank. This helical flow model is evidenced by the occurrence of bigger, muddier (suggested by low‐amplitude seismic reflections) lateral accretion deposits and gentle channel wall with downlap terminations on the gentle bank and by smaller, sandier (indicated by high‐amplitude seismic reflectors) channel fills and steep channel walls with truncation terminations on the steep bank. This helical flow circulation promotes asymmetrical depositional patterns with dipping accretion sets restricted to the gentle bank, which restricts the development of sinuosity and yields unidirectional channel migration. These results aid in obtaining a complete picture of flow processes and sedimentation in submarine channels. |
| |
| Keywords: | Bottom current‐controlled sedimentation helical flow circulation the interplay of turbidity and bottom currents unidirectionally migrating deep‐water channels West African margin |
|
|
