There does appear to be a slight (5°) change in spreading orienta- 

 tion west of F.Z. 8, the only fracture that extends across the entire 

 basin. This area (between F.Z, 8 and F.Z. 4) is also the locus of the 

 block-like basement feature extending eastward from the Eauripik Rise 

 (Fig. 2; Fig. 7, profiles 9 and 10) mentioned earlier. This feature 

 is labeled "fracture" in Figure 12, and occurs just south of (after) 

 anomaly 13. I speculate that this feature may be related to the 

 change in spreading orientation, and that its counterpart may be 

 found on the southern side of the basin by future seismic reflection 

 surveys. 



There is no indication in either the magnetic anomalies or the 

 sediment column that the East Caroline Basin experienced the sort of 

 spreading discontinuities found in the West Caroline Basin. Spread- 

 ing cessation seems to have progressed rather uniformly and perman- 

 nently from west to east across the basin as individual spreading 

 segments died out. This cessation occured over a time span of roughly 

 3 m.y., from about 31 m.y. B.P. in the west to about 28.5 m.y. B.P. 

 in the east. 



Eauripik Rise 



The Eauripik Rise (Fig. 2) is a 300 km wide arcuate (concave east- 

 ward) , north-trending bathymetric feature. Relief averages 2 km above 

 the adjacent ocean basins. 



The results of the seismic refraction work of Den and others (1971) 

 over the rise indicate a crustal "root" under the rise extending to a 

 depth of about 20 km, 14 km of which is composed of layer 3 (average 



45 



