1 I'd like to leave you with several major conclusions. The first 



2 is that the canyon environment is extremely complex, and with respect to 



3 the hypotheses we've been presented, that they are probably erosional, 



4 at least in some canyons there are both erosional and depositional 



5 environments within a single canyon. 



6 So, we can't really classify a canyon as being all erosional or 



7 all depositional. This base map shows the location of Lydonia Canyon on 



8 the southern flank of Georges Bank. I've colored the 200-meter isobath 



9 here. It is one of nine major submarine canyons which cut northward 



10 into the continental shelf, along the southern flank of Georges Bank on 



11 the order of 10 to 20 kilometers. 



12 Lydonia Canyon was selected for this experiment, because it was 



13 the canyon closest to the eight exploratory wells which were drilled 



14 along the southern flank of Georges Bank. 



15 I've just indicated here schematically the flow regime in that 



16 region of the continental shelf. In red I've shown the mean flow, which 



17 in this region is westward along the shelf at 5 to 10 cm/sec. I've 



18 indicated the rotary tidal currents which are strongest on the crest of 



19 the bank and decreased to 20 to 30 cm/sec in the region of Lydonia 



20 Canyon. 



21 I've also indicated the storm-generated currents, driven primarily 



22 by wind, which are back and forth, primarily parallel to the isobaths, 



23 which can reach speeds in these water depths of 20 to 30 cm/sec. 



24 Because the canyons cut northward into the shelf and the mean flow 



25 and the oscillatory currents, the strong ones during which we see most 



26 sediment transport are parallel to those isobaths. These currents, both 



27 the mean and the storm-generated currents, can cause flow of sediment 



28 into these canyons, and they can essentially act as one-way traps. 



29 Depending on whether the flow is to the east or the west, the 



30 particles can enter those canyons. 



31 Now I'm going to describe some details of the canyon experiment. 



32 I'll be primarily describing the physical measurements, and later this 



33 morning, Mike Bothner will take about some of the geochemical 



34 measurements made as part of the canyon experiment. 



19 



