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1.
This paper describes simulation experiments in which glucose and cellulose were reacted with polysulphide and hydrogen sulphide at ambient temperatures in an aqueous environment. Organic sulphur containing compounds were formed that yield several thiophenes upon pyrolysis/evaporation. The experiments show that interaction of carbohydrates with hydrogen sulphide or polysulphides is a possible way for carbohydrates to react in very recent sediments. From the results of this study it can be concluded that carbohydrate carbon can be preserved in sediments in a form that is resistant to microbial attack and that will have a greater potential for survival during diagenesis than the carbohydrate precursor. 相似文献
2.
This paper describes the occurrence and significance of hydrocarbons present in two bituminous marl layers and one distinct gypsum layer from a Messinian sedimentary basin, where hypersaline conditions prevailed. Several new compounds were detected and tentatively identified: of these 20R and 20S 4α, 24-dimethyl-5α(H),14β(H),17β(H) and 20R and 20S 4β,24-dimethyI-5α(H),14β(H),17β(H) cholestanes; 4-methylspirosterenes; 4,4-dimethyl-5α(H),14β(H),17β(H) pregnanes and homopregnanes are discussed in this paper. Several of these compounds might be considered as biological markers for a (hyper)saline environment. The short side chain 4-desmethylsteranes, 5α(H),14β(H),17β(H), 5α(H),14β(H),17α(H) and 5α(H),14α(H), 17α(H) pregnanes and homopregnanes, are the most abundant compounds in the extract from the gypsum sample. It is suggested that in this case these compounds do not reflect the stage of diagenesis but are related to certain organisms exclusively occurring in hypersaline environments. In addition the very low pristane/phytane ratio, often considered as an indicator for anoxicity, could also be interpreted as a useful indicator for hypersalinity. 相似文献
3.
In a study on the diagenesis of carbohydrates in a recent stromatolitic deposit (Solar Lake, Sinai) monosaccharides are quantitated after mild acid hydrolysis and gas chromatographic analysis as alditol acetates. From the depth profiles of the individual monosaccharides relative to the total organic carbon three categories of carbohydrates can be distinguished. The behaviour of the various categories upon burial is discussed in terms of their potential to become a part of the organic matter that survives geological periods. The distribution patterns of especially the mono-O-methyl monosaccharides at various depths are characteristics for the bacterial communities present in the corresponding parts of the sediment column. 相似文献
4.
H. Goossens W. Irene C. Rijpstra R.R. Düren J.W. De Leeuw P.A. Schenck 《Organic Geochemistry》1986,10(4-6)
A systematic study of the lipid composition of thirteen bacterial species and three Recent sediments (methanogenic sediment, cyanobacterial mat and evaporative gypsum crust) was undertaken in an attempt to recognize bacterial organic matter in sediments. A sequential method, which distinguishes between three different modes of occurrence of lipid moieties (free, OH−- and H+-labile), was applied. The acid-labile fractions are discussed.The three main groups of bacteria, archaebacteria, gram-positive eubacteria and gram-negative eubacteria, are easily distinguished. Methanogenic and extremely halophilic archaebacteria are characterized by the presence of diphytanyl glyceryl ether and the absence of fatty acids. The gram-positive eubacteria contain primarily iso- and anteiso-branched fatty acids whereas the gram-negative bacteria and sediments are dominated by β- and α-hydroxy fatty acids. A wide variety of H+-labile hydroxy fatty acids was observed which included several, as yet unknown, structures.β-Hydroxy fatty acids in this H+-labile mode of occurrence are exclusively present in bacteria. Their distribution patterns in sediments are considered “fingerprints” of past and present bacterial populations. The specific differences in β -hydroxy fatty acid compositions observed in the different bacteria and the three sediments investigated, suggest that amide-linked β-hydroxy fatty acid patterns are useful as markers of bacterial populations and therefore of environmental conditions. 相似文献
5.
Sulphur-containing compounds in sulphur-rich crude oils from hypersaline lake sediments and their geochemical implications 总被引:1,自引:0,他引:1
Guoying Sheng Jiamo Fu S. C. Brassell A. P. Gowar G. Eglinton Jaap S. Sinninghe Damste Jan W. de Leeuw P. A. Schenck 《中国地球化学学报》1987,6(2):115-126
Three sulphur-rich commercial crude oils have been studied, which contain sulphur as high as up to 4–12%. These samples were
collected from Tertiary hypersaline lake sediments of the Jianghan Basin, Hubei Province at different depths, but above the
oil generation threshold (2200m). FPD-GC and GC-MS data show that aromatic fractions of the crude oils are composed of different
homologues of sulphur-containing compounds, including long-chain normal alkyl-thiophenes and-thiolanes, long-chain isoprenoid-thiophenes
and -thiolanes, and benzothiophenes. It is worth noting that the distribution patterns of long-chain alkyl-thiophenes and
-thiolanes from two shallow-seated crude oils are quite similar to those of normal alkanes showing marked even-odd predominance.
It seems that the even-odd predominance of sulphur-containing compounds decreases with increasing burial depth of the crude
oils. The major component of aliphatic fraction is phytane, and similarly the major peaks of aromatic fractions also represent
C20 isoprenoid thiophenes.
Some preliminary conclusions have been drawn from the above discussion: (1) Abundant sulphur-containing compounds may be used
as an indicator of low mature or immature crude oils produced from hypersaline lake sediments; (2) Sulphur-containing compounds
are considered to be early diagenetic products of reactions between elemental sulphur or sulfides and alkanes or their precursors
(phytols, fatty acids, alcohols, etc.), or of bacterial activities, but not direct inputs of organisms. 相似文献
6.
Soxhlet-extractable organic compounds of sediments from the anoxic brine-filled Tyro basin (eastern Mediterranean) were analyzed by gas chromatography and gas chromatography-mass spectrometry. Cholesterol and 22,29,30-trisnorhopan-21-one are the major compounds identified. The occurrence of this triterpenoid ketone, as well as 22,29,30-trisnorhop-6-en-21-one and diplopterol (both tentatively identified), is ascribed to an input of microbiota living at the brine-seawater interface. 相似文献
7.
Comparison of the analytical data on the alkenes extracted from both dried and wet Messel shale sediment points to the formation of artifacts, presumably as a result of clay-catalyzed dehydration reactions. 相似文献
8.
Diatomaceous ooze of the shelf off Walvis Bay (S.W. Africa) was analysed for lipid material. The lipids from the sediment consist of a mixture of hydrocarbons, alcohols, ketones, fatty acids, sterols, carotenoid pigments and chlorophylls. The total fatty acid mixture has been analysed by capillary gas chromatography mass spectrometry and shown to consist of straight chain, iso-, anteiso- and isoprenoid acids. The environmental setting of the S.W. African shelf (Walvis Bay) makes it possible to discuss these fatty acids as markers for the fate of organic matter. The acids in the sediment point to a generation during passage of algal lipids through levels of microbial activity either on or slightly above the burial surface. 相似文献
9.
J. Klok H.C. Cox M. Baas P.J.W. Schuyl J.W. de Leeuw P.A. Schenck 《Organic Geochemistry》1984,7(1):73-84
A qualitative and partly quantitative survey of the carbohydrates encountered in acid hydrolyzates of some recent marine sediments reveals the presence of a large variety of known and hitherto unknown monosaccharides. Apart from the well known major monosaccharides a great number of minor components (notably O-methyl and deoxy monosaccharides) are encountered. These minor components are considered to originate from bacteria. Since significantly larger amounts of major monosaccharides are encountered in carbohydrates associated with bacterial cell-walls the greater part of the carbohydrate carbon in these sediments is ascribed to these structures. Superimposed on the bacterial contribution the characteristics of the carbohydrates originating from the primary producers are recognizable. The results indicate that bacterial biopolymers formed by de novo synthesis in the sediment should be considered as a potential source for the insoluble organic matter in these sediments. 相似文献
10.