FY 1986

Settling analysis of fine sediment in salt water at concentrations low enough to preclude flocculation

Ozturgut, E., and J.W. Lavelle

Mar. Geol., 69(3-4), doi: 10.1016/0025-3227(86)90047-2, 353–362 (1986)

A new method for measuring settling velocities of fine sediment in salt water at small (~1–10 mg l^–1) concentrations is outlined. The method combines conventional settling tube procedures with aliquot volume measurements using a Coulter Counter. Sensitivity of the Coulter Counter in volume measurements allow settling tube experiments to be conducted at particle concentrations that preclude flocculation from occurring during the measurement period. The procedures have been applied to samples of North Pacific clays with initial concentrations of 1.6–600 ppm. These results show by differences in settling distributions that flocculation effects occur at concentrations as low as 50 ppm. Absence of flocculation at lower concentrations is confirmed by an experiment conducted in fresh water.