Predominance of even carbon-numbered n-alkanes from lacustrine sediments in Linxia Basin, NE Tibetan Plateau: Implications for climate change

Wang, Yongli; Fang, Xiaomin; Zhang, Tongwei; Li, Yuanmao; Wu, Yingqin; He, Dajun; Wang, Youxiao

doi:10.1016/j.apgeochem.2010.07.002

Cited by 57 publications

(23 citation statements)

References 55 publications

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“…3-4, Table 3). Our study is in agreement with another study conducted by Wang et al (2010) and de Souza et al (2011), which confirmed a good correlation between the concentration of C 25 -C 31 n-alkanes and TOC in the sediments of river basins (r2 N 0.8).…”

Section: N-alkanessupporting

confidence: 83%

Characterisation of the dynamics of organic contaminants ( n -alkanes, PAHs and PCBs) in a coastal area

Syakti

Oursel

Garnier

et al. 2017

Marine Pollution Bulletin

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Section: N-alkanessupporting

confidence: 83%

Characterisation of the dynamics of organic contaminants ( n -alkanes, PAHs and PCBs) in a coastal area

Syakti

Oursel

Garnier

et al. 2017

Marine Pollution Bulletin

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“…Such a distribution of shorter‐chain n ‐alkanes has not been identified in any of the other 20 samples from the Orava‐Nowy Targ basin that are currently under investigation and in general rarely occurs in sediments. In terrestrial environments it is linked with a direct organic contribution from specific bacteria living at the oxic–anoxic interface in sediments or strictly under highly reducing conditions (Fabiańska, ; Wang et al ., ). Therefore, it appears that this atypical n ‐alkanes distribution is related to the specific methanogenic conditions, and this relationship has not been reported before.…”

Section: Discussionmentioning

confidence: 99%

Root‐related rhodochrosite and concretionary siderite formation in oxygen‐deficient conditions induced by a ground‐water table rise

et al. 2015

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Sedimentological, mineralogical, stable carbon and oxygen isotope determinations and biomarker analyses were performed on siderite concretions occurring in terrestrial silts to understand their formation and to characterize the sedimentary and diagenetic conditions favouring their growth. High δ13C values (6·4‰ on average) indicate that siderite precipitated in an anoxic environment where bacterial methanogenesis operated. The development of anoxic conditions during shallow burial was induced by a change in sedimentary environment from flood plain to swamp, related to a rise of the ground‐water table. Large amounts of decaying plant debris led to efficient oxygen consumption within the pore‐water in the peat. Oxygen depletion, in combination with a decrease in sedimentation rate, promoted anoxic diagenetic conditions under the swamp and favoured abundant siderite precipitation. This shows how a change in sedimentary conditions can have a profound impact on the early‐diagenetic environment and carbonate authigenesis. The concretions contain numerous rhizoliths; they are cemented with calcium‐rhodochrosite, a feature which has not been reported before. The rhodochrosite cement has negative δ13C values (−16·5‰ on average) and precipitated in suboxic conditions due to microbial degradation of roots coupled to manganese reduction. The exceptional preservation of the epidermis/exodermis and xylem vessels of former root tissues indicates that the rhodochrosite formed shortly after the death of a root in water‐logged sediments. Rhodochrosite precipitated during the initial stages of concretionary growth in suboxic microenvironments within roots, while siderite cementation occurred simultaneously around them in anoxic conditions. These suboxic microenvironments developed because oxygen was transported from the overlying oxygenated soil into sediments saturated with anoxic water via roots acting as permeable conduits. This model explains how separate generations of carbonate cements having different mineralogy and isotopic compositions, which would conventionally be regarded as cements precipitated sequentially in different diagenetic zones during gradual burial, can form simultaneously in shallow burial settings where strong redox gradients exist around vertically oriented permeable root structures.

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“…The values of the odd-to-even preference ratio of n-alkanes (OEP) for samples Y-5, Y-4-8, Y-4-6 and Y-4-5 are 0.68, 0.82, 0.75 and 0.84, respectively. Of n-alkanes, n-C 20 turns out to be the most abundant, showing the predominance of even-numbered species, especially those ranging from n-C 18 to n-C 22 , which is indicative of microbial activities in sediments [39]. In the extracts from the SMG and SGH oil shales (Fig.…”

Section: N-alkanes and Isoprenoidsmentioning

confidence: 99%

Source Rock Potential and Depositional Environment of Upper Permian Oil Shales of the Lucaogou Formation in the Southeastern Junggar Basin, Northwest China

Gao¹,

Wang²,

Peng³

et al. 2016

Oil Shale

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Predominance of even carbon-numbered n-alkanes from lacustrine sediments in Linxia Basin, NE Tibetan Plateau: Implications for climate change

Cited by 57 publications

References 55 publications

Characterisation of the dynamics of organic contaminants ( n -alkanes, PAHs and PCBs) in a coastal area

Characterisation of the dynamics of organic contaminants ( n -alkanes, PAHs and PCBs) in a coastal area

Root‐related rhodochrosite and concretionary siderite formation in oxygen‐deficient conditions induced by a ground‐water table rise

Source Rock Potential and Depositional Environment of Upper Permian Oil Shales of the Lucaogou Formation in the Southeastern Junggar Basin, Northwest China

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