Sediment Deposition and Distribution

If the sources of supply, initial and boundary conditions, and the transport and deposition mechanisms are adequately defined, the resultant distribution of marine sediment can be deduced. This can be done qualitatively for Long Island Sound some of the results can be put in quantitative form. 

The initial conditions at the start of the marine regime in the Sound at 8000-yr bp are shown in Fig. 15. Lacustrine mud had accumulated on part of the bottom of the lake formed behind the Mattituck sill. The sill itself, and the lake floor surrounding the lacustrine mud, was formed of deposits of glacial outwash. Most of this outwash, already submerged in fresh water, was not subject to reworking under the advancing surf zone. Small 

Fig 16. The average rate of accumulation of marine mud on the bottom of Long Island Sound over the past 8000 yr (J. Gebert, personal communication, 1976). 

Fraction of Sound bottom covered by mud Sediment supply rate from rivers 56% 

Mass per unit area of mud bottom Sediment present in the Sound 0.26 kg/(m yr) 

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