1 and flows less that 5 cm/sec, which we took as indicative as 



2 depositional environments. 



3 This shows the percentage of time in each one of those flow 



4 categories for each one of those different experiments. If you look at 



5 the velocity of magnitude greater than 20 cm/sec, and this is organized 



6 by depth from to 3,000 meters, so it's without regard to location 



7 along the continental slope, but organized by depth. 



8 You can see that the strong currents decrease very rapidly, and by 



9 500 meters, only about 5 percent of the time, or less than 5 percent of 



10 the time do the currents exceed 20 cm/sec. We've chosen that as a rough 



11 estimate of the erosional threshold for the sediments that exist there. 



12 The converse of that is also true that the velocity, the 



13 percentage of time that the currents are less than 5 cm/sec is the 



14 inverse of that, and increases to about 40 percent of the time by the 



15 time you pass 400 or 500 meters. 



16 So, the 400 to 500 meter isobath is a rough transition zone from 



17 an erosional environment, at least based on this, roughly an erosional 



18 environment to a depositional environment. 



19 Now, I've plotted on top of this the data from the canyon 



20 experiment, but the currents are so strong in these canyons that I had 



21 to use a scale which was twice as big. What I've done is transfer to a 



22 simpler graph this green line which shows the observations for all the 



23 data on the continental slope and compared that to the flows in Lydonia 



24 and Oceanographer. 



25 Here off my PC this morning is this beautiful graph. Here's the 



26 green line again showing the decrease in the percentage of currents 



27 greater than 20 cm/sec, dropping at about 500 meters, and essentially no 



28 incidents of strong currents at depths deeper than 500 meters. 



29 The canyon environments are dramatically different. In Lydonia, 



30 we see current in excess of 20 cm/sec, at depths less than 1,000 meters 



31 20 to 30 percent of the time. In Oceanographer we see them 40 to 60 



32 percent of the time. 



27 



