Oleanene, Ursene, and Other Terrigenous Triterpenoid Biological-Marker Hydrocarbons in Baffin Bay Sediments

Abstract

The aliphatic hydrocarbon fractions of eight early Miocene to Pliocene sediment samples from Hole 645E (Baffin Bay; ODP Leg 105) were investigated by gas chromatography and gas chromatography/mass spectrometry. Long, straight-chain alkanes of terrigenous origin are often present as major compounds. Other terrigenous biological markers include three oleanenes with a double bond at positions 12, 13(18), or 18, and taraxer-14-ene. Urs-12-ene is identified tentatively. In the three deepest samples, 17a(H), 18a(H), and 210(H)-28, 30-bisnorhopane is the most abundant compound. Several new compounds were detected, some of which are tentatively identified. The identification and possible significance of 23-norlupane, three A/B-ring nuclear demethylated (or A-nor-) oleanenes, and an A/B-ring nuclear demethylated (or A-nor-) urs-12-ene are discussed. The authors postulate that taraxer-14-ene isomerizes to olean-12-ene with increasing burial depth.

Geochemical characterization and palaeoenvironmental implications of lipids in Neogene lignites and lignitic shales in NW Poland

“…Varying abundances of other pentacyclic triterpenoids were identified in the saturated fractions of the samples. Olean-12-ene was often predominant, but not observed in samples 4, 13a, 20, and 24, and olean-13(18)-ene and urs-12-ene, often reported in other lignites (Ten Haven and Rullkötter, 1989;Logan and Eglinton, 1994;Rullkötter et al, 1994), were low and only in some samples. These triterpenes are alteration products of bioterpenoids, such as β-and α-amyrin, derived from angiosperms (Dev, 1989;Ten Haven et al, 1992), and also isomerize under acidic conditions to olean-13(18)-ene and urs-13(18)-ene, respectively.…”