Basins and Troughs 



233 



Table 17 



Chemical Composition of Sediments, per cent 



Spectrographic Analyses 



Chemical Analyses 



' SUicon from Griffin-Hasson Laboratories, Los Angeles (11, 9, and 10 samples, gravimetric). 

 - Nickel from Richfield Oil Corporation, Wilmington (4 samples). 

 ^ Phosphorus from Rittenberg, Emery, and Orr (1955) (colorimetric). 



2.3, lower than the average of 2.5 for red 

 clays reported by Goldberg and Arrhenius 

 (1958), probably because of the lower per- 

 centage of siUceous organic debris and of 

 wind-borne quartz in the basin sediments 

 than that in red clay. Aluminum averages 

 about 1.9 times iron in the basin sediments 

 as compared to 1.4 in red clay, perhaps be- 

 cause of the concentration of iron in the 

 fine-clay sizes, as suggested by Grim, Dietz, 

 and Bradley. Although about half the 

 sodium reported from the basin sediments 

 is in the form of dissolved solids of the inter- 

 stitial water, very little of the potassium is 

 of that origin. Instead, the potassium must 

 be chiefly from illite clay minerals. Grim, 

 Dietz, and Bradley reported an increase of 



potassium with depth in basin cores, as 

 though in response to progressive formation 

 of illite from other clay minerals during 

 diagenesis, but the present six cores show 

 no such trend, being evenly divided between 

 decrease, increase, and no change. The 

 calcium-to-magnesium ratio averages 4.7, 

 4.1, 1.9, and 1.3 in the sediments of Santa 

 Barbara Basin, Santa Catalina Basin, conti- 

 nental slope, and deep sea, respectively. 

 Because most of the magnesium is clearly 

 part of the clay mineral structure, these 

 ratios cannot be compared with those of 

 limestones reported by Chilingar (1956) to 

 have an average calcium-to-magnesium 

 ratio of 40 in Quaternary and Recent sedi- 

 ments and, of course, they are also unre- 



