1 parallel to the slope of the wall, and shows this silty sand combination 



2 of bioeroded silt fragments and shelf sand, making its way down the wall 



3 and to the floor, presumably being transported by axial currents along 



4 the walls. 



5 Now, on the floor of Oceanographer Canyon, which is one of the 



6 most energetic of the canyons we've studied, there are large bedforms 



7 that range up to 3 meters in height, sand dunes, basically, which are 



8 very clean, have wery low concentrations of silt an clay, and we feel 



9 that the fine-grained sediments are being winnowed out as the sand is 



10 being formed into these large features. 



11 The sand is moving both up and down, on the basis of the asymmetry 



12 of these bedforms, the sand is moving both up and down the canyon in 



13 different parts, and there doesn't seem to be any net transport out of 



14 the canyon. So, this could be considered a depositional area of course- 



15 grained sediments. 



16 This shows the gravel on the east rim of Oceanographer Canyon, 



17 plus the area where we have course sand along the axis and in the head. 



18 Areas where we have observed large dunes are indicated here, and 



19 these arrows indicate the net-transport direction at the time that we 



20 made the observations, based on the asymmetry of the sand dunes, so that 



21 in this region it's down canyon, in this region it was up canyon to 



22 about here, and then down canyon in this region, up canyon in that 



23 region. 



24 So, there doesn't seem to be any uniform transport direction in 



25 the canyon. 



26 The numbers indicate these are observations we made during 



27 submersible dives of bottom currents greater than 75 cm/sec, and the 



28 other two are Brad's deployments in the canyon, which showed maximum 



29 currents of 75 to 100 cm/sec. 



30 So, this slide is an attempt to summarize the sedimentary 



31 environments, in that the yellow color indicates high energy, blue 



32 moderate, and purple low. 



33 So, since there is a correlation between sediment transport and 



34 deposition and erosion and current strength, we see that the blue areas 



39 



