SECT. 3] BASIN SEDIMENTATION AND DIAGENESIS 595 



credence to the speculations on the origin of hfe. The second is to investigate 

 diagenetic processes with the ultimate goal of gaining an insight into the enigma 

 of petroleum genesis. As a result, information is now available on some specific 

 groups of organic compounds which may help solve the outstanding problems 

 mentioned above; four of these groups are discussed below. 



a. Amino acids 



The finding of proteins and amino acids in the shells of living animals by 

 Abelson (1954) aroused interest in their application to paleobiochemistry. 

 Definite changes in the stability of the proteins and polypeptides occur with age 

 of burial. An aqueous environment and heat was found to be most detrimental 

 to their preservation. x4.belson (1959) found that shells of the clam Mercenaria 

 mercenaria, an existing species but also j)resent in the Miocene, showed a loss 

 of protein with burial (a complete loss in the Miocene specimen), but a gain in 

 free amino acids. No evidence is available from this study as to the stability 

 of the individual amino acids with age. 



Working on shelf sediments from the Gulf of Mexico, Erdman, Marlett and 

 Hanson (1956) were able to show the presence of nine common amino acids, 

 while Plunkett (1957) found eight in the core from the Cariaco Trench and 

 somewhat fewer from the sediment outside the basin. Studies on the sediments 

 from Santa Barbara Basin (Saltman, unpublished data) have yielded eleven 

 amino acids. In all, the following have been isolated in marine sediments by the 

 above mentioned workers; alanine, arginine, aspartic acid, glutamic acid, 

 glycine, isoleucine, leucine, lysine, phenylalanine, proline, serine, threonine, 

 tyrosine and valine. Since the adequacy of the techniques of separation and 

 identification is questionable, interpretations based on the presence or absence 

 of particular amino acids should be reserved for a later date. 



b. Hydrocarbons 



Although reports of "paraffins" in marine sediments had been made by 

 Trask and Wu (1930), their actual isolation and identification was not effected 

 until relatively recently by Smith (1952, 1954). Apart from steroids and caro- 

 tenes, three groups of hydrocarbons are recognized: paraffin-naphthenes, 

 aromatics and asphalts. They are extracted from the dried sediment by suitable 

 solvent mixtures and separated on alumina columns. Identification is usually 

 made by infrared si:)ectroscopy. The molecular weights of the compounds are on 

 the whole high. Smith (1952, 1954) found that average weight fell in the 250 to 

 300 range. From a large number of cores, Orr and Emery (1956) isolated only 

 one compound that was liquid at room temperature. They found that the 

 paraffin-naphthenes were colorless, the aromatics yellow and the asphalts black. 



Smith (1954) found that the hydrocarbon content varied from 9 to nearly 

 12,000 parts per million of dried sample from a number of localities. Emery 

 (1960) showed that basin sediments can have nearly 1600 ppm hydrocarbons, 

 with asphalts the greatest fraction. Bonnett (1959) also found a higher content 



