Occurrence and geochemical significance of long-chain dialkylthiacyclopentanes
| Autor: | P. Albrecht, Jacques Connan, J. C. Schmid |
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| Rok vydání: | 1987 |
| Předmět: | |
| Zdroj: | Nature. 329:54-56 |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/329054a0 |
| Popis: | Small sulphur-containing molecules were first detected in petroleums and sediments many years ago1–3, but only recently have complex sulphur components related to biological markers been identified4–14. These discoveries have provided interesting information on the distribution of sulphur-containing compounds in geological samples, but the formation mechanisms of such molecules remain to be clarified. Recently, Connan et al.15 recognized the occurrence of series of long-chain sulphur-containing components in heavy sulphur-rich crude oils from carbonate basins and tentatively identified them as alkylthiacyclopentanes and alkylthiacyclohexanes on the basis of selective detection and gas chromatography/mass spectrometry studies. Here we report the conclusive identification and geochemical significance of long-chain 2,5-dialkylthiacyclopentanes of type 1 (see Fig. 4), occurring as major components in some of these petroleums, as shown for an immature carbonate crude oil from Maruejols (Oligocene Ales basin, France), containing 6.5% sulphur16. In addition to providing new information about the 'aromatic' fractions of these crude oils (which are in fact largely non-aromatic), these results give useful indications of some of the mechanisms of incorporation of sulphur into organic matter in the sub-surface environment. Furthermore, as confirmed by thermal simulation experiments, these dialkylthiacyclopentanes are thermally labile, which seems to restrict their occurrence to immature crude oils. They could therefore serve as useful maturation parameters for the early stages of petroleum formation in carbonate basins. |
| Databáze: | OpenAIRE |
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