Predicting bottom current deposition and erosion on the ocean floor

Daan Beelen, Lesli Wood

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Mapping sediment deposition and erosion by thermohaline ocean bottom currents is important for the development of ocean infrastructure, future geo resources and understanding the sedimentology of contourites and abyssal sediment wavefields. However, only a limited percentage (estimated 20%) of the ocean floor has been mapped directly through seismic or sonar imaging. To better delineate where zones of bottom current deposition and erosion exist, we develop a prediction from numerical model solutions and sedimentological measurements of the ocean floor. This is achieved by integrating three types of data, which include the following: (1) bottom current shear stress from a model run of the HYCOM numerical ocean model; (2) sedimentation rates from ocean lithospheric age and sediment thickness from the GlobSed Model; (3) the measured extents of bottom current deposits from sonar observations. Shear stresses and sedimentation rates inside and outside the mapped extents of bottom current deposits allow us to quantify the conditions that are conducive for bottom current deposition. These conditions are then extrapolated and displayed on a 1/12° arcsecond resolution map of the world's oceans and validated through comparison with known, mapped systems. Based on our prediction, around 12% of the ocean has significant deposition by bottom currents while only 1% has erosion. Most bottom current activity occurs where thermohaline currents impinge upon the ocean floor like on continental slopes or some areas of the abyssal plain. Deposition and erosion also occur where constriction of ocean bottom currents takes place as in straits and seaways. Inland basins (i.e. seas) and continental shelves are mostly disconnected from global-ocean thermohaline bottom current conveyors and, therefore, have limited bottom current deposition and erosion. Mid-ocean ridges also have little bottom current deposition due to low sediment supply.

Original languageEnglish
Pages (from-to)1985 - 2009
Number of pages25
JournalBasin Research
Volume35
Issue number5
DOIs
Publication statusPublished - Oct 2023

Bibliographical note

Funding Information:
We would like to thank the members and research staff of the Sedimentary Analogs Database and Research Consortium (SAnD) for their generous support.

Publisher Copyright:
© 2023 The Authors. Basin Research published by International Association of Sedimentologists and European Association of Geoscientists and Engineers and John Wiley & Sons Ltd.

Keywords

  • bottom current
  • contourite
  • deposition and erosion on the ocean floor
  • machine learning
  • sedimentology

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