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Carbonate dissolution and sedimentation on the mid-atlantic continental margin
Science (New York, N.Y.)
|September 3, 1982
Summary
Sediment calcium carbonate content on the Mid-Atlantic continental margin increases with depth, with a notable low-carbonate zone linked to intense dissolution. Preservation improves below 4400 meters where the Western Boundary Undercurrent is found.
Area of Science:
- Marine Geology
- Geochemistry
- Oceanography
Background:
- Sediment composition varies across continental margins.
- Oceanographic currents influence sediment diagenesis and preservation.
- Calcium carbonate content is a key indicator of marine sediment conditions.
Purpose of the Study:
- To determine calcium carbonate content in core tops along two transects.
- To investigate the relationship between carbonate content, depth, and dissolution.
- To understand the influence of the Western Boundary Undercurrent on carbonate preservation.
Main Methods:
- Analysis of core top samples from the Mid-Atlantic continental margin.
- Determination of calcium carbonate content (by weight).
- Examination of sediment dissolution indices.
Main Results:
- Carbonate content increases from ~5% on the upper slope to >30% on the upper rise.
- A low-carbonate zone (3000-4400 meters) shows evidence of intense dissolution.
- Below 4400 meters, carbonate preservation improves, correlating with the Western Boundary Undercurrent.
Conclusions:
- The Western Boundary Undercurrent significantly impacts carbonate dissolution and preservation.
- Depth and proximity to the Western Boundary Undercurrent are critical factors controlling sediment geochemistry.
- Understanding these processes is vital for paleoceanographic reconstructions.
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