Flood and tides trigger longest measured sediment flow that accelerates for thousand kilometers into deep-sea

Abstract Here we document for the first time how major rivers connect directly to the deep-sea, by analysing the longest runout sediment flows (of any type) yet measured in action. These seafloor turbidity currents originated from the Congo River-mouth, with one flow travelling >1,130 km whilst accelerating from 5.2 to 8.0 m/s. In one year, these turbidity currents eroded 1-2 km3 of sediment from just one submarine canyon, equivalent to 14-28% of the annual global-flux from rivers. It was known earthquakes trigger canyon-flushing flows. We show major river-floods also generate canyon-flushing flows, primed by rapid sediment-accumulation at the river-mouth, but triggered by spring tides weeks to months after the flood. This is also the first field-confirmation that turbidity currents which erode can self-accelerate, thereby travelling much further. These observations explain highly-efficient organic carbon transfer, and have important implications for hazards to seabed cables, or how terrestrial climate change impacts the deep-sea.

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Quartz arenites of the Cambro–Ordovician Kamouraska Formation, Quebec Appalachians, Canada: II. Eolian sands in deep-sea sedimentary gravity-flow deposits

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2014-0030 ◽

2015 ◽

Vol 52 (4) ◽

pp. 261-277 ◽

Cited By ~ 4

Author(s):

Pierre Malhame ◽

Reinhard Hesse

Keyword(s):

Sea Level ◽

Deep Sea ◽

New York State ◽

Submarine Canyon ◽

Turbidity Currents ◽

Sand Transport ◽

Dune System ◽

Barrier Beach ◽

Eolian Sand ◽

Modern Analogue

The Kamouraska Formation is a quartz-arenitic unit of latest Cambrian – earliest Ordovician age in the Quebec Appalachians that was deposited by hyperconcentrated to concentrated density flows in a meandering submarine canyon on the continental slope bordering the Iapetus Ocean, as outlined in a companion paper. Detailed petrographic study of the quartz arenites of the Kamouraska Formation combined with scanning electron microscopy of grain surface textures suggests that the quartz sands are of eolian origin having been derived from an inland desert or, less likely, a barrier beach dune system. Transport of the mature quartz-arenitic sand onto the shelf and deposition into the deep sea was not accompanied by substantial mixing with material from other sources thus preserving the inherited eolian characteristics. A modern analogue for the eolian interpretation of the deep-sea quartz-arenite beds is as follows: thick, Late Pleistocene eolian sand beds on a modern abyssal plain in the East Atlantic referred to as eolian-sand turbidites that were deposited in the deep sea during glacial sea level lowstands when eolian sand transport to canyon heads was enabled by an exposed and shortened shelf. Similarly, an established sea level lowstand at the Cambro–Ordovician boundary would have facilitated the introduction of eolian sand of the Kamouraska Foundation into canyon heads on the upper slope from where turbidity currents and related density flows were triggered. Correlation of the Kamouraska Formation with the quartz arenites of the Cairnside Formation of Quebec (Keeseville Formation in northern New York State, Nepean Formation in southern Ontario) links the deep-sea deposits with remnants of an inland dune system.

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Depositional architecture, evolution and controlling factors of the Miocene submarine canyon system in the Pearl River Mouth Basin, northern South China Sea

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2021.104990 ◽

2021 ◽

Vol 128 ◽

pp. 104990

Author(s):

Hongxun Tian ◽

Changsong Lin ◽

Zhongtao Zhang ◽

Hao Li ◽

Bo Zhang ◽

...

Keyword(s):

South China Sea ◽

Northern South China Sea ◽

River Mouth ◽

Submarine Canyon ◽

Controlling Factors ◽

Pearl River ◽

Pearl River Mouth Basin ◽

Architecture Evolution ◽

The Pearl River ◽

Depositional Architecture

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Corallimorpharians (Anthozoa: Corallimorpharia) from the Argentinean Sea

Zootaxa ◽

10.11646/zootaxa.4688.2.5 ◽

2019 ◽

Vol 4688 (2) ◽

pp. 249-263

Author(s):

DANIEL LAURETTA ◽

MARIANO I. MARTINEZ

Keyword(s):

Deep Sea ◽

Submarine Canyon ◽

Sister Group ◽

Southwestern Atlantic ◽

Sea Anemones ◽

Northern Patagonia ◽

Stony Corals ◽

Internal Morphology ◽

Southwestern Atlantic Ocean ◽

First Time

Corallimorpharians are a relative small group of anthozoan cnidarians, also known as jewel sea anemones. They resemble actiniarian sea anemones in lacking a skeleton and being solitary, but resemble scleractinian corals in external and internal morphology, and they are considered to be the sister group of the stony corals. Corynactis carnea (=Sphincteractis sanmatiensis) is a small, common and eye catching species that inhabits the shallow water of northern Patagonia and the Argentinean shelf up to 200 m depth. Corallimorphus rigidus is registered for the first time from the southwestern Atlantic Ocean. It is a rather big and rare species that inhabits only the deep sea. Only two specimens were found at 2934 m depth in Mar del Plata submarine canyon, in an area under the influence of the Malvinas current, which may explain its occurrence. These two species are the only two known jewel sea anemones in the Argentinean sea and are reported and described herein.

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Strong contribution of diatom resting spores to deep-sea carbon transfer in naturally iron-fertilized waters downstream of South Georgia

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/j.dsr.2016.05.002 ◽

2016 ◽

Vol 115 ◽

pp. 22-35 ◽

Cited By ~ 24

Author(s):

M. Rembauville ◽

C. Manno ◽

G.A. Tarling ◽

S. Blain ◽

I. Salter

Keyword(s):

Deep Sea ◽

South Georgia ◽

Carbon Transfer ◽

Resting Spores

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Late Quaternary marine sediment accumulation in fiord-shelf-deep-sea transects, Baffin Island to Baffin Bay

Quaternary Science Reviews ◽

10.1016/0277-3791(87)90006-0 ◽

1987 ◽

Vol 6 (3-4) ◽

pp. 231-243 ◽

Cited By ~ 10

Author(s):

John T. Andrews

Keyword(s):

Marine Sediment ◽

Deep Sea ◽

Late Quaternary ◽

Sediment Accumulation ◽

Baffin Island ◽

Baffin Bay

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Isostasy amplifies relative sea-level change on continental-scale deltas

10.5194/egusphere-egu21-13678 ◽

2021 ◽

Author(s):

Sara Morón ◽

Mike Blum ◽

Tristan Salles ◽

Bruce Frederick ◽

Rebecca Farrington ◽

...

Keyword(s):

Sea Level ◽

Drainage Basin ◽

Sediment Accumulation ◽

River Mouth ◽

Feedback Mechanism ◽

Landscape Dynamics ◽

Passive Margin ◽

Sea Level Changes ◽

Isostatic Compensation ◽

Continental Scale

<p>The nature and contribution of flexural isostatic compensation to subsidence and uplift of passive margin deltas remains poorly understood. We performed a series of simulations to investigate flexural isostatic responses to high frequency fluctuations in water and sediment load associated with climatically-driven sea-level changes. We use a parallel basin and landscape dynamics model, BADLANDS, (an acronym for BAsin anD LANdscape DynamicS) that combines erosion, sedimentation, and diffusion with flexure, where the isostatic compensation of the load is computed by flexural compensation. We model a large drainage basin that discharges to a continental margin to generate a deltaic depocenter, then prescribe synthetic and climatic-driven sea-level curves of different frequencies to assess flexural response. Results show that flexural isostatic adjustments are bidirectional over 100-1000 kyr time-scales and mirror the magnitude, frequency, and direction of sea-level fluctuations, and that isostatic adjustments play an important role in driving along-strike and cross-shelf river-mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea-level changes set up a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.</p>

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