Sedimentation on young ocean floor at the Mid-Atlantic Ridge, 29 degrees N | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS


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  Sedimentation on young ocean floor at the Mid-Atlantic Ridge, 29 degrees N

Publication Type:

Journal Article


{MARINE GEOLOGY}, Volume {148}, Number {1-2}, p.{1-8} (0)


{Measurements of the sediment cover over mid-ocean ridges are potentially useful for tectonic and volcanic problems because sediment thickness variations may reflect variations in seafloor age. In profiler records recently collected with the deeply towed TOBI system, however, we find that sediments on 0-2.5 Ma seafloor do not thicken systematically with distance from the spreading axis as would be expected from increasing seafloor age. Average sedimentation rates calculated from the thicknesses show some tendency to increase with depth as found elsewhere on the Mid-Atlantic Ridge. Many of the deposits drape basement topography and occur on outlying promontories, so sediment is probably deposited from suspension in the bottom nepheloid layer rather than from turbidity currents or other gravity flows. Enhanced sedimentation rates in deeper areas, therefore, occur because of enhanced suspended load within the bottom nepheloid layer or reduced bottom movement which allow particles to settle from suspension. The profiler records reveal a variation in the style of sedimentation from draping and localised pending on young seafloor, to accumulation in large turbidite ponds farther off-axis, which probably reflects the progressive accumulation in source areas and, due to sedimentation, progressively smoother pathways favourable to turbidity currents. (C) 1998 Elsevier Science B.V. All rights reserved.}