title: Genesis of petroleum hydrocarbons in marine sediments.
abstract: Distribution patterns of isopentane and normal pentane in marine sediments show a reversal in slope at a subsurface temperature of about 90 degrees 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 degrees C) chemical reactions yielding predominately secondary carbon structures, and (iii) high-temperature (> 90 degrees C) cracking reactions at great depth yielding predominately straight carbon chains.
authors.forename: J M
authors.initials: JM
authors.lastname: Hunt
authors.forename: J K
authors.initials: JK
authors.lastname: Whelan
authors.forename: A Y
authors.initials: AY
authors.lastname: Huc