as 65 times higher than rates on the continental slope at comparable depth and 

 seven times higher than those measured on the continental shelf. 



The frequency of sediment resuspension and its variability in intensity 

 were also indicated in the sediment-trap data. An instrument was placed in 

 some of the traps which deposited a layer of white teflon powder on the 

 accumulating sediment at 10 day intervals (Figure 11). The mass of sediment 

 collected between each time interval varied by an order of magnitude. The 

 variability in flux of trapped sediment correlated, in most cases, with high- 

 energy current events recorded by the current meters. It is during these 

 events that the coarsest sediment was resuspended and collected in the 

 sediment traps. 



Not only is the resuspended sediment flux relatively intense and frequent 

 in the canyon axis, but it also influences a significant portion of the water 

 column. Traps placed between 20 and 102 mab exhibited a similar pattern of 

 alternating fine and coarse sediment, indicating that resuspended sediments 

 were being exposed to at least the lower 100 m of the water column. 



These same processes of sediment resuspension seem to be intensified in 

 the axis of Oceanographer Canyon as well. During one deployment, the flux of 

 trapped material was 30 percent higher in Oceanographer Canyon than in Lydonia 

 Canyon at the same water depth. 



RATES OF SEDIMENT ACCUMULATION AND SEDIMENT SOURCES 



There is a growing body of information which suggests that the head of 

 Lydonia Canyon is accumulating sediments and that the continental shelf 

 contributes at least some of this material. On the basis of high-resolution, 

 seismic-reflection and sidescan-sonar data, Twichell (1983) mapped areas of 

 post-glacial sediment fill and suggested that accumulation of fine sediments 

 winnowed from the adjacent shelf was probably active. The carbon-14 age of 

 total organic carbon deposited with these sediments was determined on two 



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