1 Lydonia and Oceanographer, that those ray paths of energy from the 



2 . outside in the deep ocean are different. 



3 I don't know quite how the canyon comes to equilibrium, there is 



4 some complex balance between the erosion of those currents as they 



5 propagate up--the erosional potential of those currents as they 



6 propagate up the current, and the response to the seabed. 



7 There may be some structural control in the slopes of the canyons 



8 also, but it's a really complex oceanographic problem looking at how 



9 energy propagates into these topographic features and how it mixes. I 



10 think that's my simple explanation about why they may be different. 



11 DR. BOEHM: What do you feel is responsible for the silt and clay 



12 environment on the shelf around the head, the entire depositional 



13 feature? 



14 DR. BUTMAN: I don't know. I don't have a good hypothesis for 



15 that? 



16 DR. BOEHM: Do you feel it's an active deposition? 



17 DR. BUTMAN: Mike, are you going to address that at all about the 



18 accumulation rates around the edge of the canyon? 



19 DR. BOTHNER: I think that the data that I have is more inside the 



20 canyon head. To answer Paul's question, I wonder if [inaudible] is it 



21 really a little bit deeper, it wouldn't have to be much. 



22 DR. BUTMAN: I've looked at it a little bit, and it doesn't look 



23 like that there isn't a bathymetric feature which is causing that. As 



24 Mike says, it would only have to be a few meters to make a difference in 



25 terms of wave base, which is what is causing a lot of the movement 



26 there. 



27 I think the high resolution profiles, as I recall, show that 



28 that's a fairly thin layer of fine-grained sediments overlying coarser 



29 sands underneath, which suggest it's depositional. 



30 I don't have a good — actually it was very surprising to us to 



31 actually define that feature that there were these lobes of fine-grained 



32 sediment apparently associated with the head of the canyon. I don't 



33 have a good hypothesis for why it's there. 



31 



