812 



NAFE AND DRAKE 



[CHAF. 29 



be expected, for processes of cementation occurring over an extended time 

 interval should have the effect of increasing the velocity. 



In Fig. 8 points representing observed velocities are distinguished according 

 to locality. The observations from deep-water stations appear to have velocities 



o North Atlantic - shallow 

 X North Atlantic - deep 



• Bloke Plateau 



• Gulf of Mexico - shallow 

 ■ Gulf of Cadiz- shallow 



• Bloke Ploteou area - deep 

 n Gulf of Mexico - deep 



4 6 



Depth of burial (km) 



10 



Vip. 8. ( 'oinpressional velocity-depth of burial data derived from seismic refraction 

 measurements. The indicated dejath of burial does not include water depth. The 

 slowest rate of increase of velocity with depth occurs in the case of deep-water sedi- 

 ments (water depth > 2000 fm). 



distinctly lower than those from shallow-water stations with the same depth of 

 burial. It should be pointed out that most shallow-water observations in Fig. 8 

 are from the continental shelf of northeastern America. Shallow-water environ- 

 ments with velocity-depth curves similar to those for deejj-water sediments are 



