STRATIGRAPHY OF THE DEEP-SEA FLOOR 



73 



SYLVANIA 



BIKINI 



SEA SURFACE 



-"^^ 77 4.74 



(4FT£/> DAITT, I9$4) 



(a) 



SEA SURFACE 



PACIFIC OCEAN 

 FIRST LAYER UNCONSOLIDATED ^S^ELIIE:^'''^ 



SECOND LAYER: ? 



VEL.: 4.66 TO 6.24 KM/SEC 



■ //^y-^^/^y^/z/y^^^-^^-^^ ' ^^v^^^yy //////'/' /'/ ' /V ' ^ '- V ////'^/////' / ' / ' ^ ' /V/'y/'y// ' yyy^yy^y^//y -=; 



THIRD LAYER: BASALT 



VEL.: 6.42 TO 7.10 KM/SEC 



(AFTCK RAITT, I9it) 



(b) 



BARBADOS RIDGE 



SEA SURFACE 



2 2 



(AFTCR J. EWINC mt a/., liSTj 



Fig. 9. Layered structure of the sea floor in selected areas: (a) N-S section 

 through Bikini and Sylvania (Raitt, 1954) ; {b) diagrammatic structure in the north- 

 east Pacific Basin (Raitt, 1956); (c) E-W generalized structure across Barbados 

 Ridge (Ewing et al., 1957). 



the increased thicknesses under the equatorial current areas thus 

 require no special explanation although increased rates of deposi- 

 tion are probably a factor because age is a factor in degree of 

 lithification. 



Geologic history indicates that the distribution of calcareous 

 deposits during the late Cretaceous and early Tertiary were prob- 

 ably more widespread than today. This is especially true, as noted 

 by Arrhenius (1952), in areas adjacent to present calcareous sedi- 

 mentation. This probability, plus the discovery of high-velocity 



