Lacustrine biomass: An significant precursor of high wax oil

Huang, Haiping; Zheng, Yabin; Zhang, Zhanwen; Li, Jinyou

doi:10.1007/bf03183992

Cited by 12 publications

(1 citation statement)

References 17 publications

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“…5). Long-chain n-alkanes were originally thought to be derived predominantly from higher plants (Tissot and Welte, 1984;Tegelaar et al, 1989), but increasingly more studies revealed that algae and other aquatic organisms can also produce large amounts of these high molecular-weight waxy alkanes (e.g., Huang et al, 2003;Feng et al, 2007;Bechtel et al, 2012). Feng et al (2007) and Bechtel et al (2012) suggested that Botryococcus braunii may have contributed long-chain n-alkanes to the Songliao Paleo-lake deposits.…”

Section: Changes In Terrigenous Organic Matter Input and Primary Prodmentioning

confidence: 99%

Paleoenvironmental reconstruction of the Late Santonian Songliao Paleo-lake

Cao

Peng

et al. 2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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Section: Changes In Terrigenous Organic Matter Input and Primary Prodmentioning

confidence: 99%

Paleoenvironmental reconstruction of the Late Santonian Songliao Paleo-lake

Cao

Peng

et al. 2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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Distribution and significance of C 40 + alkanes in the extracts of Cretaceous source rocks from the Songliao Basin

et al. 2007

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Source rock extracts and crude oils from the Songliao Basin were analyzed by high-temperature gas chromatography (HTGC), gas chromatography-mass spectrometry (HTGC-MS) and gas chromatography-isotope ratio-mass spectrometry (GC-IRMS), for high molecular-weight alkanes. The distributions of n-alkanes in the Nenjiang Formation extracts are in the C 14 -C 63 range; a bimodal distribution occurs in the 21 C − and C 21 -40 regions. The C 30 -C 37 n-alkanes are accompanied by C 29 -C 35 hopanes, whereas the high molecular-weight C 45 -C 47 n-alkanes co-occur with abundant isoalkanes, alkylcyclohexanes and alkylcyclopentanes. The high δ 13 C values of the n-alkanes and the microscopic maceral compositions indicate a highly diversified organic source input for the Nenjiang Formation source rocks, ranging from aquatic plants, blue alge-bacteria, to land plant material. In contrast, n-alkanes in the rock extracts of the Qingshankou Formation are characterized by a single modal distribution, with relatively low abundances of C 29 -C 35 hopanes, but high molecular-weight isoalkanes, alkylcyclohexanes and alkylcyclopentanes. The relatively low δ 13 C values of C 22 -C 44 n-alkanes and organic material compositions indicate that the source rocks in the Qingshankou Formation contain dominantly type I algal organic matter. The relative abundance of 40 C + compounds in source rocks changes little at low maturity stage, but decreases drastically at higher maturity levels, with a concurrent reduction in the odd/even carbon predominance. In crude oils, in contrast, the relative abundance of 40 C + compounds appears to relate closely with the oil source and oil viscosity.Songliao Basin, source rock, high-temperature gas chromatography (HTGC), high-temperature gas chromatography-mass spectrometry (HTGC-MS), gas chromatography-isotope ratio-mass spectrometry (GC-IRMS).The 40 C + high molecular-weight alkanes in crude oil and source rock samples can be readily examined using HTGC [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . This molecular-weight range shows quite different carbon number distributions from those of the C 22 -C 35 alkanes in routine conventional GC analysis [17] , thus providing important information on oil wax deposition [2,11,13] , organic source input, source rock depositional environment [5,7,12,15] , and oil biodegradation [3,6,14] .Available data indicate that sometimes it is necessary to pre-concentrate the high molecular weight fractions from oil and source rock extract prior to HTGC analysis of the so-called ceresin wax (dominated by 40 C + ) or phaneritic wax fraction (middle and low molecularweight 40 C − compounds) [7] . As a result, the lack of compounds in other molecular-weight ranges often jeopardizes a meaningful comparison and subsequent

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Microfossils and molecular records in oil shales of the Songliao Basin and implications for paleo-depositional environment

Feng

Fang²,

Wang³

et al. 2009

Sci. China Ser. D-Earth Sci.

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Citation: Feng Z H, Fang W, Wang X, et al. Microfossils and molecular records in oil shales of the Songliao Basin and implications for paleo-depositional environment.Several oil shale beds, over 10 m thick, occur at the base of the first member of the Upper Cretaceous Qingshankou Formation (K 2 qn 1 ) in the Songliao Basin. They act both as excellent source rocks for conventional oil and as potential oil deposit for shale oil production. Here we combine micropaleontology with organic geochemistry to investigate the paleo-depositional environment and organic source characteristics of the oil shales and black shales. Our results indicate that algal remains are dominant microfossils in K 2 qn 1 oil shales, and their relatively high abundance suggests a major algal thriving event during the oil shale deposition. The presence of fresh water and brackish water species, Sentusidinium, Vesperopsis and Nyktericysta, and marine or brackish water deltaic and lagoonal species such as Kiokansium and Dinogymniopsis demonstrate that this paleo-continental lake was influenced by marine transgressions at the time of K 2 qn 1 oil shale formation. The extremely low pristine/phytane ratios, relatively high abundance of gammacerane and 4-methyl steranes, and low δ 13 C values of C 14 -C 37 n-alkanes in the oil shale organic extracts indicate the deposition of oil shales in anoxic and highly stratified water columns and the significant contribution of lacustrine algae to sedimentary organic matter. High molecular-weight paraffinic hydrocarbons with unusually high abundance of nC 43 , nC 45, and nC 47 may be related to special algal species associated with marine transgression events. The giant water body of Songliao paleo-lake and the change in the organic and chemical environment (such as nutrition source and water column salinity) associated with seawater transgression into the lake are among the most important reasons for oil shales in the Songliao Basin being different from mudstone and oil shale in other rifted basins.

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Lacustrine biomass: An significant precursor of high wax oil

Cited by 12 publications

References 17 publications

Paleoenvironmental reconstruction of the Late Santonian Songliao Paleo-lake

Paleoenvironmental reconstruction of the Late Santonian Songliao Paleo-lake

Distribution and significance of C 40 + alkanes in the extracts of Cretaceous source rocks from the Songliao Basin

Microfossils and molecular records in oil shales of the Songliao Basin and implications for paleo-depositional environment

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