738 



GRIFFIN AND GOLDBERG 



[CHAP. 26 



One permutation upon the source area pattern is the introduction of Ter- 

 tiary sediments to the surface deposits. This phenomenon is well known in 

 certain parts of the Pacific (Riedel, 1957) and may account for anomalously high 

 montmorillonite concentrations in certain North Pacific areas. The following 

 section develops evidence that at least some of the depositional parameters in 

 the North Pacific during the Tertiary were quite similar to present-day para- 

 meters in the South Pacific. 



CAPRICORN BP 50 14°55'N 124°12'W 



+ I — \ — rVT 



100 



(/I 



200- 



z 



z 300 



UJ 



o 500 



m 



X 



t 600 



UJ 



o 



700 



800. 



T \ T 



n — \ — \ — I 



III I I 



10 20 30 40 50 



^7A PEAK AREA / 10 A PEAK AREA X 4 ^Je aS' \-] 



I I \ L 



100 



200 



300 



400 



- 500 



600 



700 



10 20 



PERCENT QUARTZ 



800 



Fig. 8. The quartz, M/I and chlorite values in Capricorn 50 BP as a function of depth. 



4. Vertical Distribution 



A. North Pacific 



The distribution of clay minerals in the North Pacific falls into two categories 

 of variation versus depth profiles : 



( 1 ) There is a continuous decrease in the Mjl ratio with depth in a few cores 

 taken very close to shore. A concomitant increase in the 4.7/5.0 A ratio and 

 a decrease in the 7.1/10 A ratio was observed. The 3,5/3.3 A ratio remained 

 constant with dej^th. 



(2) The Mil ratio shows abrupt changes with depth where Tertiary sediments 

 are encountered. In Capricorn 50 BP, the typical Mjl ratio discontinuity, due 

 to sediment passing downwards from the Recent to the Tertiary, is accompanied 

 by large discontinuities in the 4.7/5.0 and 3.5/3.3 A ratios. Below the dis- 

 continuity the 10, 5.0, 4.7, 3.5 and 3.3 A jDeaks were nearly or completely 

 absent (Fig. 8), whereas the 17 A peak increased in intensity. 



