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that enough suspended matter has been transported into the<br />

region to account for the volume of the transparent layer<br />

if all the suspended matter were deposited, but it is<br />

unlikely that total deposition ever occurred. The discrep-<br />

ancy is partially resolved when foraminiferal tests,<br />

216<br />

composing perhaps 20% of the bottom sediment, are considered.<br />

However, it seems likely that either water volume transports<br />

or suspended matter concentrations were higher at times<br />

during the geologic evolution of the Greater Antilles Outer<br />

Ridge than they are now. Pulses of increased AABW flow into<br />

the area (see Chapter IV), for example, may have co~tributed<br />

substantial amounts of sediment to the Greater Antilles<br />

Outer Ridge in the past.<br />

In summary, suspended sediment transported to the<br />

Greater Antilles Outer Ridge by the Western Boundary Under-<br />

current is both a likely and a reasonable source of sediment<br />

for the transparent layer. Grain size, composition, total<br />

volume of sediments, and current regimes are all in<br />

reasonabl.e agreement wi th the requi rements of a model of<br />

current-controlled deposition.<br />

,<br />

)<br />

)

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