F-23 

 this high frequency motion might be transferred to the 

 rotor. Post-cruise calibration of the meter was consistent 

 to within 2 cm/sec over the range of 1-50 cm/sec. 



The measured velocities are sufficient to transport silts 

 and fine sands in traction bedload. The detection of 

 strong currents on both the walls and in the axial thalwegs 

 is consistent with the photographic observations of exposed 

 outcrops or rippled surfaces in both areas. Although Ross 

 (1969) concluded that a blanket of fine-grained sediment 

 in Lydonia Canyon was indicative of little or no current 

 activity our measurements show that adequate transport 

 velocities are commonly reached. It is indeed possible that 

 local topographic features interfere with seasonal thalweg 

 velocities and down-canyon transport of sediment. 

 Temperature and Salinity Measurements 



In situ temperatures and salinities were measured in all 

 three canyons using thermisters on the camera sled and by 

 expendable bathythermographs. The sled system provides a 

 temperature reading for every 2 minutes of the sled run. 

 This translates to a measurement approximately every 50-75 

 meters along the sled track. Bathythermograph profiles were 

 made in each canyon, one in the shallower head of the canyon 

 and one in the deeper mouth of the canyon (Fig. F-14) . 

 Both profiles were centered over the thalweg. A thermal 

 maximum is seen at a depth between 100-150 meters. The 

 maximum is approximately 12 C and marks the top of the 

 permanent thermocline. A 7-8° C minimum occurs at a depth 



