QUESTIONS 



Teal asked why Oceanographer and Lydonia Canyons are so different. 

 Butman responded that the current strength in the canyon depends on geometry 

 (wall slope and bottom slope) and the density structure in the water column. 

 These parameters control the propagation and intensification of energy near 

 the bottom. In some canyons, the bottom slope and water density may intensify 

 currents toward the canyon head. In other cases energy will be reflected back 

 out of the canyon. In Oceanographer Canyon and Lydonia Canyon there appears 

 to be a difference. It is a complex oceanographic problem, and there has been 

 little attempt to model the propagation of energy through the canyon using 

 realistic topography and density. 



Boehm asked why silt gets deposited around the canyon head on the shelf. 

 Butman responded that he didn't know. The thickness of the silt-plus-clay 

 near the canyon head is relatively thin. 



Teal asked whether there were any severe events during the study. Butman 

 answered no and that, for the two year observational period, any two-to-four 

 months were representative of the remaining months. There was very little 

 variability in low frequency energy fluctuations but a large change in the 

 high frequencies. There was some correlation between the occurrence of warm- 

 core rings at the canyon mouth and the strength of the current fluctuations at 

 the canyon head. Flow in the canyon was generally not correlated with flow on 

 the shelf. 



Kraeuter asked where the sediments were coming from. Butman responded 

 that they apparently come from the shelf. Some sediments from the middle part 

 of the canyon may be transported toward the head. This is a rate problem. 

 However, the present study has been process-oriented and does not specifically 

 address rates, though rates are important to the hypotheses in question. 



- 21 



