SUMMARY 



The significant results and conclusions from the bottom sediment investigations 

 in the TOTO by this Office and previous investigations by others are summarized 

 be I ow : 



1 . The TOTO is a long, narrow channel in the Great Bahama Bank which gradu- 

 ally increases in depth from about 700 fathoms in the southern cul-de-sac area to 

 1,300 fathoms in the northern portion at the commencement of Northeast Providence 

 Channel. 



2. The flanks of the TOTO are steep (15 to 20°) bare rock walls to depths of 

 100 to 200 fathoms. Below this depth to the bottom of the channel the slope is more 

 gentle, incised by gullies normal to the Bank edge and sediment covered. 



3. The sediments on the floor of the channel are: 



a. Almost wholely composed of calcium carbonate, 



b. Dominantly silt-sized particles with a slight increase in sand in sediments 

 collected from central reaches of the channels, 



c. Composed predominantly of the tests of planktonic foraminifera, pteropods, 

 and reef detritus, and 



d. in general, poorly sorted. 



4. A reducing environment prevails in the sediments on the flanks and, to a 

 lesser degree in the cul-de-sac, while an oxidizing environment prevails in the 

 sediments in the flat central reaches of the northern, elongated portion of the channel. 



5. Sediment density is greatest in the axial region and lowest in the near-flank 

 and cul-de-sac areas; conversely, water content, void ratio, and porosity are lowest 

 in the axial region and highest in the near-flank and cul-de-sac areas. 



6. Sediment density generally increases with depth in the sediment while water 

 content, void ratio, and porosity decrease. 



7. Over one-half of the sediment column sampled in the axial and cul-de-sac 

 areas is the result of turbidity current deposition, while the near-flank sediments 

 appear to be primarily the result of particle-by-particle accumulation from the over- 

 lying water column. 



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