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Title: Eddy-driven sediment transport in the Argentine Basin: Is the height of the Zapiola Rise hydrodynamically controlled?

In this study, we address the question whether eddy-driven transports in the Argentine Basin can be held responsible for enhanced sediment accumulation over the Zapiola Rise, hence accounting for the existence and growth of this sediment drift. To address this question, we perform a 6 year simulation with a strongly eddying ocean model. We release two passive tracers, with settling velocities that are consistent with silt and clay size particles. Our experiments show contrasting behavior between the silt fraction and the lighter clay. Due to its larger settling velocity, the silt fraction reaches a quasisteady state within a few years, with abyssal sedimentation rates that match net input. In contrast, clay settles only slowly, and its distribution is heavily stratified, being transported mainly along isopycnals. Yet, both size classes display a significant and persistent concentration minimum over the Zapiola Rise. We show that the Zapiola Anticyclone, a strong eddy-driven vortex that circulates around the Zapiola Rise, is a barrier to sediment transport, and hence prevents significant accumulation of sediments on the Rise. We conclude that sediment transport by the turbulent circulation in the Argentine Basin alone cannot account for the preferred sediment accumulation over the Rise. We speculate that resuspensionmore » is a critical process in the formation and maintenance of the Zapiola Rise.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computational and Statistical Sciences Division.
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division.
  3. University of Oxford, Oxford (United Kingdom). Department of Earth Sciences.
  4. Woods Hole Oceanographic Institution, Woods Hole, MA (United States). Department of Physical Oceanography.
  5. Royal Netherlands Institute for Sea Research, den Burg (Netherlands). Department of Physical Oceanography.
Publication Date:
OSTI Identifier:
1240444
Report Number(s):
LA-UR-14-28687
Journal ID: ISSN 2169-9275
Grant/Contract Number:
AC52-06NA25396
Type:
Published Article
Journal Name:
Journal of Geophysical Research. Oceans
Additional Journal Information:
Journal Volume: 120; Journal Issue: 3; Journal ID: ISSN 2169-9275
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES