Basins and Troughs 



matter of basin sediments may be seen to 

 exhibit a general downward decrease upon 

 which are superimposed minor irregularities 

 related to grain size (Fig. 192). The coarse- 

 grained layers found in all basins have a low 



229 



organic content which evidently results from 

 the much more rapid deposition of these 

 layers than of the intervening finer green 

 muds. Such a rapid deposition must serve 

 to dilute the organic matter, which is de- 



60 



50 



u 



Z 



o 



cr 



< 40 



o 



2 

 o 

 _i 

 < 



U 30 

 U 



o 



z 

 u 

 o 

 a: 20 



Ld 

 Q. 



ro 



% 



s CONTINENTAL SLOPE 



o OFFSHORE BAS/NS 



. NEARSHORE BASINS 



+ LOS ANGELES BASIN 



• TOP OF CORES 



VAy^ 







%••• . 

 •»•• 







0.1 



0.2 0.3 0.4 0.5 



PERCENTAGE NITROGEN 



0.6 



0.7 



Figure 196. Relationship of organic nitrogen to calcium carbonate in basin sediments. Note seaward increase of nitrogen 

 from nearshore basins to ones at intermediate distance from shore and then decrease in basins far from shore and 

 continental slope. Values of nitrogen in Los Angeles Basin should be increased about 50% to be comparable with sub- 

 surface data from present basins, to adjust for late diagenetic losses of nitrogen. 



