DEEP-SEA DEPOSITS 95 



obtained in the vicinity, this region of the equatorial 

 Atlantic must be especially prone to tectonic changes, 

 in which differential movements of the mafic or ultra- 

 mafic rocks have led to a crushing of the material into 

 fragments, with a subsequent sliding down the steep 

 incline from the ridge into the cavity of the Romanche 

 Deep (See Figure 33, a microphotograph of a typical 

 sample of the Romanche Deep sand). 



Fig. 33. Sand from the Romanche Deep 



A very different type of deep-sea sand is found about 

 1,500 nautical miles farther west, shghtly north of the 

 equator. Here, from a depth of about 4,400 meters, the 

 core-sampler brought up a core nearly nine meters 

 long, the uppermost parts of which consisted of fairly 



