Daily bathymetric surveys document how stratigraphy is built and its extreme incompleteness in submarine channels
Daily bathymetric surveys document how stratigraphy is built and its extreme incompleteness in submarine channels
Turbidity currents are powerful flows of sediment that pose a hazard to critical seafloor infrastructure and transport globally important amounts of sediment to the deep sea. Due to challenges of direct monitoring, we typically rely on their deposits to reconstruct past turbidity currents. Understanding these flows is complicated because successive flows can rework or erase previous deposits. Hence, depositional environments dominated by turbidity currents, such as submarine channels, only partially record their deposits. But precisely how incomplete these deposits are, is unclear. Here we use the most extensive repeat bathymetric mapping yet of any turbidity current system, to reveal the stratigraphic evolution of three submarine channels. We re-analyze 93 daily repeat surveys performed over four months at the Squamish submarine delta, British Columbia in 2011, during which time >100 turbidity currents were monitored. Turbidity currents deposit and rework sediments into upstream-migrating bedforms, ensuring low rates of preservation (median 11%), even on the terminal lobes. Large delta-lip collapses (up to 150,000 m
3
) are relatively well preserved, however, due to their rapidly emplaced volumes, which shield underlying channel deposits from erosion over the surveyed timescale. The biggest gaps in the depositional record relate to infrequent powerful flows that cause significant erosion, particularly at the channel-lobe transition zone where no deposits during our monitoring period are preserved. Our analysis of repeat surveys demonstrates how incomplete the stratigraphy of submarine channels can be, even over just 4 months, and provides a new approach to better understand how the stratigraphic record is built and preserved in a wider range of marine settings.
channel-lobe transition zone, crescentic bedform, stratigraphic completeness, submarine channel, submarine landslide, turbidity current
231-247
Vendettuoli, D.
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Clare, M. A.
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Hughes Clarke, J. E.
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Vellinga, A.
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Hizzet, J.
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Hage, S.
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Cartigny, M. J.B.
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Talling, P. J.
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Waltham, D.
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Hubbard, S. M.
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Stacey, C.
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Lintern, D. G.
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1 June 2019
Vendettuoli, D.
16879a32-0874-4edf-a368-52ec101c8967
Clare, M. A.
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Hughes Clarke, J. E.
81b97b31-58a8-474e-b693-c4f20a54d992
Vellinga, A.
9957dfd4-70a8-4327-b66c-af7f718a0e75
Hizzet, J.
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Hage, S.
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Cartigny, M. J.B.
d252d7b1-16c6-47b1-bf86-8087070934ce
Talling, P. J.
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Waltham, D.
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Hubbard, S. M.
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Stacey, C.
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Lintern, D. G.
107a4f6b-6da4-458e-a4be-dcf2a41714d1
Vendettuoli, D., Clare, M. A., Hughes Clarke, J. E., Vellinga, A., Hizzet, J., Hage, S., Cartigny, M. J.B., Talling, P. J., Waltham, D., Hubbard, S. M., Stacey, C. and Lintern, D. G.
(2019)
Daily bathymetric surveys document how stratigraphy is built and its extreme incompleteness in submarine channels.
Earth and Planetary Science Letters, 515, .
(doi:10.1016/j.epsl.2019.03.033).
Abstract
Turbidity currents are powerful flows of sediment that pose a hazard to critical seafloor infrastructure and transport globally important amounts of sediment to the deep sea. Due to challenges of direct monitoring, we typically rely on their deposits to reconstruct past turbidity currents. Understanding these flows is complicated because successive flows can rework or erase previous deposits. Hence, depositional environments dominated by turbidity currents, such as submarine channels, only partially record their deposits. But precisely how incomplete these deposits are, is unclear. Here we use the most extensive repeat bathymetric mapping yet of any turbidity current system, to reveal the stratigraphic evolution of three submarine channels. We re-analyze 93 daily repeat surveys performed over four months at the Squamish submarine delta, British Columbia in 2011, during which time >100 turbidity currents were monitored. Turbidity currents deposit and rework sediments into upstream-migrating bedforms, ensuring low rates of preservation (median 11%), even on the terminal lobes. Large delta-lip collapses (up to 150,000 m
3
) are relatively well preserved, however, due to their rapidly emplaced volumes, which shield underlying channel deposits from erosion over the surveyed timescale. The biggest gaps in the depositional record relate to infrequent powerful flows that cause significant erosion, particularly at the channel-lobe transition zone where no deposits during our monitoring period are preserved. Our analysis of repeat surveys demonstrates how incomplete the stratigraphy of submarine channels can be, even over just 4 months, and provides a new approach to better understand how the stratigraphic record is built and preserved in a wider range of marine settings.
Text
1-s2.0-S0012821X19301815-main
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More information
Accepted/In Press date: 23 March 2019
e-pub ahead of print date: 4 April 2019
Published date: 1 June 2019
Keywords:
channel-lobe transition zone, crescentic bedform, stratigraphic completeness, submarine channel, submarine landslide, turbidity current
Identifiers
Local EPrints ID: 430078
URI: http://eprints.soton.ac.uk/id/eprint/430078
ISSN: 0012-821X
PURE UUID: cfbc27bb-01da-4841-afeb-82a40019d49b
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Date deposited: 11 Apr 2019 16:30
Last modified: 17 Mar 2024 12:24
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Contributors
Author:
D. Vendettuoli
Author:
M. A. Clare
Author:
J. E. Hughes Clarke
Author:
A. Vellinga
Author:
J. Hizzet
Author:
S. Hage
Author:
M. J.B. Cartigny
Author:
P. J. Talling
Author:
D. Waltham
Author:
S. M. Hubbard
Author:
C. Stacey
Author:
D. G. Lintern
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