Tetracyclic diterpenoid hydrocarbons in some Australian coals, sediments and crude oils

Variation in the content and distribution of biomarkers in two closely situated peat and lignite deposits

“…The presence of diterpenoid compounds in these samples is evidence of the influence of higher plant debris, particularly of conifers, in the formation of the sediments (Noble et al, 1985;Venkatesan et al, 1986). In the peat we observed a predominance of diterpenoid adds whereas the lignite contained a predominance of defunctionalized and aromatized diterpenes, suggesting its higher maturity.…”

“…The greater abundance of these compounds in the lignite samples suggests a larger contribution from resinous higher plants in the lignite than in the According to those authors, the great abundance of these compounds and the absence of their saturated analogs implies that the precursor plant material has been rapidly buried and preserved from oxidation and biodegradation and, consequently, diagenetic reduction of the diterpenes has been limited. A saturated compound was identified by its mass spectrum (base peak at m/z 123 and molecular ion at m/z 274) as 16¢(H)-phyllocladane (VIH), the isomer most commonly found in some other fignites (Serantoni et al, 1978;Noble et al, 1985;Alexander et al, 1987). Kaurenes and phyllocladenes (unsaturated diterpenes) are typical components of conifer resins belonging to Podocarpaceae, Araucariaceae and Cupressaceae families (Hanson, 1968;Thomas, 1969).…”

“…Biomarkers in low-rank coals have received increasing attention in the past few years (Chaffee and Johns, 1983;Noble et al, 1985;Farnum et al, 1984;Chaffee et al, 1986;Hazai et al, 1988Hazai et al, , 1989Sunai and Gaines, 1989;Wang and Simoneit, 1990) because they constitute intermediate components in the coalification process and, therefore, the lipid precursors have not yet undergone long-term diagenetic and catagenic alterations. Numerous studies have shown that significant changes in biomarker distributions occur with increasing coal rank (Brooks and Smith, 1969;Radke et al, 1980).…”

Determination of the molecular signature of fossil conifers by experimental palaeochemotaxonomy – Part 1: The Araucariaceae family

“…They are identified according to the spectra published by Noble et al (1985). Their spectra are all characterized by a molecular ion at m/z 274 and a base peak at m/z 123 (C 20 H 34 ).…”

Molecular geochemical approach to the Paleoceanographic assessment of Neogene sediments of Yashima area, Akita Basin, Japan.

“…Diterpenoids, which are regarded as specific compounds of conifers (e.g., Noble et al, 1985;Chaffee et al, 1986) Dinosterane/4-desmethylsterane ratio, the ratio of the compound specific to dinoflag ellatesto that widely occurring in algae, is rela tivelyhigher in the bottom part of the Onna gawaFormation and the Tentokuji Formation than in the middle and upper parts of the On nagawaFormation and the Funakawa Forma tion (Fig. 4), indicating a decrease of the con tributionof dinoflagellates at ca.…”