... for the characterization of depositional environments, organic matter, and maturation of the source rocks. These samples contain gamaceranes, 8,14-open-hopanes, diterpenoid hydrocarbons, and diasteranes. The abundant gamaceranes correspond to the preference of even carbon atoms. The highest gamacerane occurs...

... constituent, accounting for up to 70 per cent of the coal. Biomarker distributions in saturated extract fractions display a number of characteristic features, including high abundance of sesqui- and diterpenoids, high pristane to phytane ratios, low CPI, prominence of alkyl- and methyl-alkylcyclohexanes, low...

... are characterized by odd-over-even normal alkane distributions, high pristane/phytane and high hopane/sterane ratios, dominance of C 29 sterane homologs, local abundance of diterpenoid compounds, and low abundance of tricyclic terpanes. Geochemical correlation with four petroleums from the Junggar, Tarim...

... the established generation potential of the Woodford Shale. Several unique Mississippian biomarkers were identified, including diterpenoids and extended tricyclic terpanes. Macerals of the Mississippian rocks exhibit dominance of lamalginite and bituminite, whereas Woodford macerals are high in telalginite. Based...

... or soluble products. Thermal products contributing to conventionally sourced crude oils would be primarily naphthalenes or indans derived from the breakdown of diterpenoids and triterpenoids in the resinites. Bendoraitis (1974) provided an example of this type of contribution from resinites in the crude...

... content (in μg g −1 TOC ) Sample n -Alkanes C 27 Diasteranes C 27 Steranes C 28 Steranes C 29 Diasteranes C 29 Steranes Hopanes Benzohopanes Sesquiterpenoids Diterpenoids Alkyl -N P+MP PAHs 4-6 rings 2 317.1 1.9 7.3 5.5 11.2 16.7 149.0 19.8 12.0 39.7 35.2 5.8...

... again, reaches maxima in the Batalpashinsk Formation (0.65), and decreases in the Septarian Formation. A subtle upward increase can be observed in the lower Miocene units. The concentrations of diterpenoids and triterpenoids, biomarkers for gymnosperms and angiosperms, respectively, reach maxima...

...L. R. Snowdon; T. G. Powell ABSTRACT Petroleum has been found in Canadian frontier basins in reservoirs which have undergone low levels of thermal alteration (vitrinite reflectance ≤ 0.6%R o ). Paraffin indices, stable carbon and hydrogen isotope contents, pristane to nC 17 ratios, and diterpenoid...

... alkane and pristane/C 17 alkane log-log plot with values for each site. Vectors and bivariate ranges highlight general trends of redox state and organic matter source as determined by previous work (e.g., Peters et al. 2005 ). Pentacyclic triterpenoids and tricyclic diterpenoids are often...

... compounds identified include sesquiterpenoid, diterpenoid and triterpenoids. The only sesquiterpenoid compound identified is 8β (H) homodrimane. Major diterpenoids identified are given in the Table 3 . The triterpanes identified include tetracyclic secohopanes, pentacyclic compounds including hopanes...

... investigation of oils from a number of basins in this region has revealed interesting and unusual distributions of biomarkers. The compound classes that were analyzed included sesquiterpenoids, diterpenoids, triterpenoids, and steranes. From the information obtained, it has been possible to correlate the oils...

... box marks the magnified peak displayed under the whole chromatogram. Mass spectra of compounds a (podocarpa-8,11,13-trien-12-ol), b and c are also pointed out. Many cyclic sesqui- and diterpenoids preserved in sedimentary rocks are land plant biomarkers. Sesquiterpenoids are produced by most...

... ). These assignments suggest that the brown part contains smaller PAH molecules such as diterpenoids. Diterpenoids are one of the most typical and stable biomolecules and commonly used as biomarkers in sediments ( Killops and Killops 2005 ). The molecular structure of abietic acid (C 20 H 30 O 2 ) is shown in Appendix...

... of plant-derived n-alkane hydrocarbons (C 23 -C 33 ) except the extract of immature WL, wherein triterpenoids and unsaturated alkanes dominate ( Lu, 1987 ). The dominance of diterpenoids and triterpenoids in RMC bitumen, and triterpenoids from WL may indicate that some biomarker precursors are unbound...

...)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS) for 10 min at 80 °C to facilitate compound identification (diterpenoids and sesquiterpenoids) using a Varian Saturn 2200 gas-chromatography (GC)/ion-trap mass spectrometer (70 eV; mass-to-charge ratio, m / z , = 45–600; 0.8 s/scan). The GC had an HP...

... contains standard abietane, pimarane, and labdane skeletons ( Thomas 1969 , 1970 ). Low to medium-gravity naphthenic crudes occur in the Tuna (some zones), Dolphin, Lakes Entrance, Perch, and Flathead fields of the Gippsland basin ( Thomas, 1982 ). The presence of tricyclic diterpenoids in the Tuna...

... defensive and protective biological purposes. Resins largely comprise monoterpenoids, diterpenoids, and triterpenoids and/or phenolic compounds ( Langenheim, 2003 ). Diterpenoids are the major products of conifer (gymnosperms) derived resins, whereas triterpenoids are products of angiosperm resins ( Otto...

...Fig. 5 —Relative distribution histograms of diterpenoids and triterpenoids based upon m/z 191 mass chromatograms. EBBS = southeastern Bering Sea; CI = lower Cook Inlet; NS = Norton Sound; NB = Navarin basin; 17 α (H),21 β (H)-hopanes, diastereomers indicated by ̅..̅; 17 β (H),21 α (H)-hopanes...