1 A PARTICIPANT: In Lydonia, then, there is still a net transport 



2 of sediment out of that canyon or is that strictly a depositional 



3 environment that's just building up? 



4 DR. VALENTINE: Nobody knows that. It's the same as in 



5 Oceanographer Canyon, that sediment is moving around a lot, but we don't 



6 know if any is going out, or if it's just going up and back and forth, 



7 back and forth. 



8 I know that at about 1,300 meters in Oceanographer Canyon, there 



9 is just a fine-grained sediment on the canyon floor, there are no 



10 bedforms and no coarse sand, that's at 1,300 meters. We have data down 



11 to about 750 meters. 



12 So, we don't know where the transition is from energetic, coarse 



13 bedform environment down to this rather tranquil, fine-grained sediment. 



14 We don't know if anything is leaving the canyon. 



15 I think the fine-grained stuff is leaving the canyon, because it's 



16 coming down onto the floor, but it's not in the sediments. If you look 



17 along the edge of the lower parts of the canyon walls, you can see lots 



18 of fragments of silt and clay that have been bioeroded in small buildups 



19 of fine-grained sediment. 



20 Out in the axis itself, that sand is very clean. If you look 



21 closely, these little--! don't want to go on and on about this, but 



22 these little fragments get into the sand, the coarse sand, and are 



23 rolled around and soften up, we've found them armored with sand grains 



24 as they are disintegrating, and eventually they are eroded away. 



25 DR. HECKER: I just wanted to point out that, sort of to support 



26 that, that I had an Alvin dive in Oceanographer Canyon at about 1,500 



27 meters to 1,600 meters, well -developed sand ripple marks all long the 



28 axis. 



29 I've not seen a similar area in Lydonia at that depth, but ^ery, 



30 very well --such that there's hardly any fauna in there. So, it must be 



31 in constant motion. There's no attached forms or sea pens or anything. 



32 DR. VALENTINE: That's interesting. 



33 DR. HECKER: That was 1,500 to 1,600 meters, very low. 



34 DR. VALENTINE: You saw a lot of sea pens in Lydonia, didn't you? 



45 



