气候变化领域集成服务门户(CCPortal): Effect of channel tributaries on the evolution of submarine channel confluences (Espírito Santo Basin, SE Brazil)

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DOI	10.1130/B35082.1
	Effect of channel tributaries on the evolution of submarine channel confluences (Espírito Santo Basin, SE Brazil)
	Qin Y.; Alves T.M.; Constantine J.A.; Gamboa D.; Wu S.
发表日期	2020
ISSN	167606
起始页码	263
结束页码	272
卷号	132 期号:2021-01-02
英文摘要	Confluences are geomorphologic features fed by distinct channel tributaries that record the contribution of multiple sediment sources. They are key features of both fluvial and submarine channels in geomorphologic and sedimentologic terms. Here, we use high-quality three-dimensional seismic data from SE Brazil to document the response of a submarine channel confluence to turbidity currents originating from a tributary. The studied channel system consists of a west tributary, an east tributary, and a postconfluence channel, with the last two comprising the main channel at present. Downstream from the confluence, changes in planform morphology and architecture were found due to the effect of turbidity currents sourced from the west tributary channel. A channel bend in the main channel curved toward the west when it was first formed but later curved toward the east, and so remains until the present day. This process led to the migration of the confluence point ~500 m to the east, and changed the bed morphology from discordant (where the beds of tributaries and main channels meet at an unequal depth) to concordant (where the beds of tributaries and main channels meet at approximately the same depth). In addition to the channel bend near the confluence, two other bends further downstream recorded significant changes with time, increasing channel sinuosity from 1.11 to 1.72. These three channel bends near the confluence accumulated a large volume of sediment at their inner banks, generating depositional bars. Multiple channel forms within the depositional bars indicate the occurrence of large-scale lateral migration near the confluence. Hence, turbidity currents from the west tributary are shown to influence the submarine channel by promoting lateral channel migration, confluence migration, increases in channel sinuosity, and the formation of large depositional bars. These variations near the confluence reveal a change in tributary activity and a shift in sediment sources from east to west on the continental shelf. Such a shift suggests variations in sedimentary processes on the continental shelf probably due to avulsions on Doce River Delta. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184873
作者单位	Laboratory of Marine Geophysics and Geo-resources, Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China; 3D Seismic Laboratory, School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom; Department of Geosciences, Williams College, Clark Hall, 947 Main Street, Williamstown, MA 01267, United States; British Geological Survey, Cardiff University, Main Building, Room 0.73, Park Place, Cardiff, CF10 3AT, United Kingdom
推荐引用方式 GB/T 7714	Qin Y.,Alves T.M.,Constantine J.A.,et al. Effect of channel tributaries on the evolution of submarine channel confluences (Espírito Santo Basin, SE Brazil)[J],2020,132(2021-01-02).
APA	Qin Y.,Alves T.M.,Constantine J.A.,Gamboa D.,&Wu S..(2020).Effect of channel tributaries on the evolution of submarine channel confluences (Espírito Santo Basin, SE Brazil).Bulletin of the Geological Society of America,132(2021-01-02).
MLA	Qin Y.,et al."Effect of channel tributaries on the evolution of submarine channel confluences (Espírito Santo Basin, SE Brazil)".Bulletin of the Geological Society of America 132.2021-01-02(2020).