Genesis of Petroleum Hydrocarbons in Marine Sediments

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Science  18 Jul 1980:
Vol. 209, Issue 4454, pp. 403-404
DOI: 10.1126/science.209.4454.403


Distribution patterns of isopentane and normal pentane in marine sediments show a reversal in slope at a subsurface temperature of about 90°C. The data indicate that three types of reactions are involved in pentane formation: (i) biological origin at the sediment surface, (ii) low-temperature (< 90°C) chemical reactions yielding predominately secondary carbon structures, and (iii) high-temperature (> 90°C) cracking reactions at great depth yielding predominately straight carbon chains.