Time- and Space-Resolved Measurements of Deposition under Turbidity Currents

  1. William McCaffrey,
  2. Ben Kneller and
  3. Jeff Peakall
  1. F. De Rooij and
  2. S. B. Dalziel

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304275.ch15

Particulate Gravity Currents

Particulate Gravity Currents

How to Cite

De Rooij, F. and Dalziel, S. B. (2001) Time- and Space-Resolved Measurements of Deposition under Turbidity Currents, in Particulate Gravity Currents (eds W. McCaffrey, B. Kneller and J. Peakall), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304275.ch15

Editor Information

  1. School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK

Author Information

  1. Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 24 APR 2001

ISBN Information

Print ISBN: 9780632059218

Online ISBN: 9781444304275

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Keywords:

  • time- and space-resolved measurements of deposition under turbidity currents;
  • parameters of experiments with lock-release;
  • parameters of constant-flux experiments;
  • deposition under turbidity currents;
  • lock-release currents and lock-release currents in confined environment;
  • continuous release currents;
  • technique based on measuring vertical electrical resistance of sediment layer

Summary

This chapter describes experiments measuring the instantaneous sediment deposition rates for a turbidity current. These measurements were obtained using a recently developed technique capable of very accurate measurements of sediment layer thickness, from which the concentration in the current could be derived. Three types of experiments were performed: lock-releases, lock-releases in a confined environment and continuous releases. It was found that turbidity currents from a lock-release form a head, where the particle concentration is highest and under which the largest deposition occurs. The initial decrease in particle concentration within the head is induced by the entrainment of ambient fluid. A maximum in the final layer thickness occurs when the current slows down and the turbulence has decayed to favour detrainment rather than entrainment. Deposition dominates the flow at later stages and the concentration decreases. When the current encounters a vertical wall it is reflected and deposits on top of the deposit formed earlier. A turbidity current from a continuous source attains a steady state with a fixed run-out length. The data suggest that the concentration in the steady state decays exponentially away from the source leading to a bed thickness with a similar exponential profile.