LONG-CHAIN 3-ISOPROPYL ALKANES - A NEW CLASS OF SEDIMENTARY ACYCLIC HYDROCARBONS

Novel C-27 and C-29 3-isopropyl alkanes have been unambiguously identi fied in sediments from the Kimmeridge Clay Formation through synthesis of a C-29 standard. The covarying concentrations and similar stable c arbon isotopic compositions of C-21 and C-23 n-alkanes, C-25 and C-27 iso alkanes, and C-27 and C-29 3-isopropyl alkanes suggest a common, t hough unknown, biological source. It may be that these compounds are a ll products of an unknown biosynthetic process ultimately leading to t he formation of isopropyl alkanes. Copyright (C) 1998 Elsevier Science Ltd.