SECT. 3] 



CROSS-CORRELATION OF DEEP-SEA SEDIMENT CORES 



835 



A well defined interdependence between coiling direction and temperature 

 tolerance has been found in Globigerina pachyderma (Ericson, 1959). On the 

 other hand, no interrelationship between coiling direction and surface water 

 temperature is discernible in the geographical distributions of dextral and 

 sinistral populations of Globorotalia truncatulinoides (Fig. 1) and G. hirsuta. 



3. Time Equivalence of the Faunal Zones 



If these Pleistocene faunal zones are to serve as indicators of variation in 

 relative rates of sediment accunmlation from place to place, their time- 

 equivalence must be more rigorously assessed than is usually necessary in 

 stratigraphical geology where a few tens of thousands of years one way or the 



Depth 

 West 



V9-28 



4305 m 



VI4-5 

 3365 m 



V9-27 



4515m 



AI80-76 



3515m 



AI80-74 

 3330 m 



AI80-73 



3750 m 



AI80-72 

 3840 m 



Great Circle Distance 1300 Kilometers 



l007oLefl IOO%R l007oL 

 Warm Cold W 



IOO%R IOO%L l007oR IOO%L IOO%R l007oL 

 C W C W C W 



IOO%R IO0%L I007=R IOO%L 



c w c w 



East 



IOO%Right 

 C 



I meter 



Top of 

 Paileniat. 



Obl'QuilOC 



zone 



:] 



<i 



:^ 



<a 



Sampled at 10 cm intervals 

 ^Climatic Variation <; Coiling percentages 



Globorotalia truncatulinoidesl^ 



I meter 



Fig. 2. The equatorial suite of cores. 



other are negligible in comparison with the gross time intervals involved. 

 The radiocarbon method of dating is of little use here because of its limited 

 range. It is, in fact, directly applicable only to the horizon defined by the 

 rather abrupt appearance of Globorotalia menardii at the base of the uppermost 

 post-glacial zone in cores from the equatorial and mid-latitude Atlantic. 

 Radiocarbon assays of samples from above and below this horizon indicate 

 that it is essentially isochronous within the suite of cores sampled (Ericson et al., 

 1956). 



Perhaps the strongest argument for close time equivalence of the faunal zones 

 over wide areas is the present distribution of the various planktonic species in 

 the North Atlantic. In the east-west dimension their present distribution is 

 truly ocean-wide. It appears reasonable to suppose, therefore, that the faunal 

 zones of the suite of cores shown in Fig. 2 are essentially isochronous even 



28— s. Ill 



