Daily bathymetric surveys document how stratigraphy is built and its extreme incompleteness in submarine channels
| Type | Article |
|---|---|
| Date | 2019-06 |
| Language | English |
| Author(s) | Vendettuoli D.1, 2, Clare M. A.1, Clarke J. E. Hughes3, Vellinga A.1, 2, Hizzet J.1, 2, Hage Sophie 1, 4, Cartigny M. J. B.4, Talling P. J.4, Waltham D.5, Hubbard S. M.6, Stacey C.7, Lintern D. G.7 |
| Affiliation(s) | 1 : Univ Southampton, Natl Oceanog Ctr, Waterfront Campus, Southampton SO14 3ZH, Hants, England. 2 : Univ Southampton, Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England. 3 : Univ New Hampshire, Ctr Coastal & Ocean Mapping, Durham, NH 03824 USA. 4 : Univ Durham, Dept Geog & Earth Sci, Durham, England. 5 : Royal Holloway Univ London, Dept Earth Sci, London, England. 6 : Univ Calgary, Dept Geosci, Calgary, AB T2N 1N4, Canada. 7 : Geol Survey Canada, Inst Ocean Sci, Ottawa, ON, Canada. |
| Source | Earth And Planetary Science Letters (0012-821X) (Elsevier), 2019-06 , Vol. 515 , P. 231-247 |
| DOI | 10.1016/j.epsl.2019.03.033 |
| WOS© Times Cited | 54 |
| Keyword(s) | stratigraphic completeness, submarine channel, turbidity current, crescentic bedform, submarine landslide, channel-lobe transition zone |
| 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. (C) 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
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