Normal fatty acids in sediments

Normal fatty acids have been found by several investigators in a number of sediments ranging in age from Precambrian to Recent. This paper summarizes these occurrences. A variety of molec‐ular distributions have been observed. In most sediments, even‐carbon‐numbered normal fatty acids are much more abundant than those with odd carbon numbers; in some sediments, however, concentrations of even‐ and odd‐carbon‐numbered normal fatty acids are about equal. Normal fatty acids have been postulated as pos‐sible precursors for normal paraffin hydrocarbons in petroleum because of 1) structural similarities between the two kinds of molecules, 2) ubiquity of fatty acids in biological materials, 3) fatty acid‐normal paraffin relationships in sediments, and 4) distribution of normal paraffins in some crude oils. Evidence suggests that normal fatty acids may be precursors for many normal paraffins of intermediate and high molecular weights found in petroleum. Detailed mechanisms of chemical reactions by which normal paraffins can be de‐rived from fatty acids in sediments under geo‐logically reasonable conditions have yet to be defined.