Organic Constituents 



277 



has only limited application in revealing the 

 history of organic matter in sediments, and 

 it must be supplemented by other kinds of 

 chemical analyses. Some that have been 

 used are general proximate analyses; others 

 are specific for particular kinds of organic 

 materials. 



Proximate composition 



Most of the published data on proximate 

 composition of organic matter in sediments 

 was done by Trask (1932). The most de- 

 tailed of his analyses of recent sediments 

 were made for two samples: one from Lake 

 Maracaibo and one from his station 418 at 

 580 meters in Santa Barbara Basin located 

 within 10 km of the positions of the later 

 cores collected by the University of Southern 

 California. Results for these two samples 

 were similar and are averaged together in 

 Table 24. Also Table 24 Hsts the average 

 results that Trask obtained for two Miocene 



and one Eocene shale from California and 

 his (1939) tabulation of analyses of sessile 

 algae and zooplankton by Waksman, Carey, 

 and Reuszer (1933). Comparison of the 

 four sets of data shows a decrease in hemi- 

 cellulose, cellulose, nitrogenous compounds 

 (largely proteins), nonnitrogenous water- 

 soluble compounds, and nonnitrogenous 

 acid-soluble compounds during the transi- 

 tion from algae through sediments to rocks. 

 Resistant lignin-humus complexes show a 

 complementary increase with time, and 

 other materials are little changed. The 

 changes, decrease of nonresistant and in- 

 crease of resistant compounds, are about 

 what we would expect from chemical and 

 geological considerations of oxidation. Rel- 

 atively rapid regeneration of proteins is also 

 supported by the increase with depth of the 

 C/N ratio of the sediments and by the 

 measured release of ammonia from the 

 sediments. 



Since the completion of Trask's studies, 



Ether extract — includes 

 oils, fats, pigments, 

 and sulfur compounds 



Alcohol extract — includes 

 waxes, alkaloids, pigments etc. 



Hemicellulose 



Cellulose 



Nitrogenous compounds 

 Simple proteins and 



amino acids 

 Complex proteins and 



simple compounds 

 Resistant compounds 



10 



^From Trask (1932, p. 200; 1939, p. 443). 



^ Does not include 6 per cent chitin as reported by Waksman, Carey, and Reuszer (1933). 



^ Reported as pentosans (Trask, 1939). 



