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Journal of Earth Science 2013年第2期24卷 170-178页

作者：向树元曾方明王国灿喻建新 Faculty of Earth Sciences China University of Geosciences Geological Survey of China University of Geosciences Laboratory of Salt Lake Geology and Environment Qinghai Institute of Salt LakesChinese Academy of Sciences

This study provides the n-Alkane and pollen records of the Holocene loess at Balong Town, Dulan County, Qinghai Province, and the environmental changes reconstructed from both records agreed well. Three stages of past climate change were deciphered by variations of the n-Alkane and pollen proxies. Before 5 370 a BP, the climate was warm-dry but slightly humid, corresponding to the Mid-Holocene climatic optimum; 5 370-3 830 a BP, the climate changed alternatively between warm-dry slightly humid and warm-dry, indicating the transition from the Mid-Holocene climatic optimum to the Late Holocene cold period; after 3 830 a BP, the climate was mainly warm-dry. The warm cool and extremely dry climate during 3 040-2 600 a BP was recorded by both the n-Alkane and pollen proxies, suggesting the environment evolved into desert or salt lake, in accordance with the cold and highly frequent natural disaster period in the Western Zhou Dynasty （ca. 2 996-2 721 a BP） in China.

关键词： Qaidam Basin Holocene n-Alkane loess environmental change.

Empirical relationship between leaf wax n-AlkaneδD and altitude in the Wuyi,Shennongjia and Tianshan Mountains,China:Implications for paleoaltimetry

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Empirical relationship between leaf wax n-alkaneδD and alti...

甘肃窑街中侏罗世油页岩单体烃碳同位素分析对比研究

中国科学院地质与地球物理研究所第11届（2011年度）...

作者： Pan Luo~(a,*),Ping’an Peng~b,Gerd Gleixner~c,Zhuo Zheng~d,Zhonghe Pang~a,Zhongli Ding~a a Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China b Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China c Max Planck Institute for Biogeochemistry,Jena 07745,Germany d Department of Earth Sciences,Sun Yat-sen University,Guangzhou 510275,China

Estimating past elevation not only provides evidence for vertical movements of the Earth’s lithosphere,but also increases our understanding of interactions between tectonics,relief and climate in geological history. Development of biomarker hydrogen isotope-based paleoaltimetry techniques that can be applied to a wide range of sample types is therefore of continuing importance.Here we present leaf wax-derived n-Alkane 8D (δD) values along three soil altitudinal transects,at different latitudes,in the Wuyi,Shennongjia and Tianshan Mountains in China,to investigateδD gradients and the apparent fractionation between leaf wax and precipitation(ε). We find that soilδD track altitudinal variations of precipitation 8D along the three transects that span variable environment conditions and vertical vegetation spectra.An empiricalδD-altitude relation is therefore established in which the averageδD lapse rate of - 2.27±0.38‰/100 m is suitable for predicting relative paleoelevation change(relative uplift).The application of this empirical gradient is restricted to phases in the mountain uplift stage when the atmospheric circulation had not distinctly changed and to when the climate was not arid.An empiricalδD-latitude-altitude formula is also calculated:δD = 3.483LAT - 0.0227ALT - 261.5, which gives the preliminary spatial distribution pattern ofδD in modern China. Mean value ofε in the extreme humid Wuyi Mountains is quite negative(-154‰),compared to the humid Shennongjia(-129‰) and the arid(but with abundant summer precipitation) Tianshan Mountains(- 130‰), which suggests aridity or water availability in the growing season is the primary factor controlling soil/ sedimentε.Along the Tianshan transects,values ofε are speculated to be constant with altitude;while along the Wuyi and Shennongjia transects,ε are also constant at the low-mid altitudes,but become slightly more negative at high altitudes which could be attributed to overestimates of precipitation 8D or the vegetation shift to grass/conifer. Additionally,a reversal

关键词： leaf wax n-Alkane deuterium/hydrogen isotopic ratio inverse altitude effect paleoelevation paleoaltimetry

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质谱学报 2005年第z1期26卷 55-56页

作者：杜丽李立武孟仟祥房嬛王广李中平孙敏卓丁万仁中科院地质与地球物理所兰州油气研究中心甘肃兰州730000

n-Alkanes is widely used in the study of geologic body, which occupies 50%-80% of the saturated hydrocarbons commonly. The biogenetic implication of these compounds hold a very important value for the evaluation of all source rock, so it is used as biomarker to backward the biogenetic source of deposit organic matter. In order to find the difference of the isotopic composition of different organic compounds before and after complexion the oil shale in Yaojie, Gansu sample was performed by 5 molecular sieve adsorptipon to study the variation of the isotope compositions of n-Alkanes, isoalkanes and cyclanes. On the basis of the previous work, the mini-sized Soxhlet extraction set with a hot reflux device was adopted to enhance the recovery of samples and diminish the loss of light components in the tested samples.

关键词： carbon isotope 5 molecular sieve n-Alkane Soxhlet extraction

Analysis of imbibition of n-Alkanes in kerogen slits by molecular dynamics simulation for characterization of shale oil rocks

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Petroleum Science 2022年第3期19卷 1236-1249页

作者： Qian Sang Xin-Yi Zhao Hui-Min Liu Ming-Zhe Dong Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Management Center of Oil&Gas Exploration of Shengli Oilfield Branch Company SINOPECDongying257001ShandongChina Department of Chemical and Petroleum Engineering University of CalgaryCalgaryABCanadaT2N 1N4

Shale oil formations contain both inorganic and organic media.The organic matter holds both free oil in the pores and dissolved oil within the kerogen molecules.The free oil flow in organic pores and the dissolved oil diffusion in kerogen molecules are coupled together.The molecular flow of free n-Alkanes is an important process of shale oil accumulation and production.To study the dynamics of imbibition process of n-Alkane molecules into kerogen slits,molecular dynamics(MD)simulations are conducted.Effects of slit width,temperature,and n-Alkane types on the penetration speed,dynamic contact angle,and molecular conformations were analyzed.Results showed that molecular transportation of n-Alkanes is dominated by molecular structure and molecular motion at this scale.The space-confinement conformational changes of molecules slow down the filling speeds in the narrow slits.The n-Alkane molecules with long carbon chains require more time to undergo conformational changes.The high content of short-chain alkanes and high temperature facilitate the flow of alkane mixtures in kerogen slits.Results obtained from this study are useful for understanding the underlying nanoscale flow mechanism in shale formations.

关键词： Molecular flow Imbibition n-Alkane Kerogen slit Molecular dynamics simulation

Experimental data and modeling for excess enthalpies of 2-Pentanol with n-Alkanes(C7–C9) at T =(293.15, 298.15 and 303.15) K

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1661-1669页

作者： Dongwei Wei Mengying Li Jing Ma Baohe Wang Key Laboratory for Green Chemical Technology of Ministry of Education Research and Development Center for Petrochemical TechnologyTianjin UniversityTianjin 300072China

Excess molar enthalpies,H^E,for the binary mixtures of 2-pentanol with n-Alkanes(n-heptane,n-octane,and nnonane)have been determined at three different temperatures T=(293.15,298.15 and 303.15)K and normal atmospheric pressure over the entire composition range using a Calvet microcalorimeter.All mixtures show endothermic mixing with the maximum values of the excess enthalpies occurring in the n-Alkane-rich region.The H^Edata are smoothed using Redlich–Kister equation.The applicability of the Treszczanowicz–Benson,ERAS,Renon–Prausnitz and Chen–Bagley models to correlate H^Eof studied mixtures is tested,and the agreement between experimental and theoretical results is satisfactory.Each model includes a self-association equilibrium constant that represents hydrogen bonding and an adjustable parameter that reflects physical interactions.

关键词： Excess molar enthalpy 2-Pentanol n-Alkane Redlich–Kister equation Correlation

Habitat Influence on the Molecular, Carbon and Hydrogen Isotope Compositions of Leaf Wax n-Alkanes in a Subalpine Basin, Central China

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Journal of Earth Science 2020年第4期31卷 845-852页

作者： Chaoyang Yan Yiming Zhang Yanzhen Zhang Zhiqi Zhang Xianyu Huang State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430078China Hubei Key Laboratory of Critical Zone Evolution School of Geography and Information EngineeringChina University of GeosciencesWuhan 430078China

Epidermal leaf waxes of terrestrial higher plants have been widely utilized for the reconstructions of paleoenvironment and paleoclimate in peat deposits. In this study, specimens of four plant species growing in both peatland and non-peatland habitats were retrieved to compare their molecular, carbon(δ13 C) and hydrogen(δ2 H) isotopic compositions of leaf wax n-Alkanes from a closed subalpine basin in Central China. Three of the four species show quite higher total concentrations of n-Alkanes in the relatively dry non-peatland setting than in the peatland. In addition, the δ2 H values of long-chain n-Alkanes are generally less depleted in the peatland and are comparable among different plant species, which is interpreted as the influence of inundation condition and the possible limited supply of photosynthetic products. This study reveals different patterns of plant wax molecular and isotopic compositions between peatland and the surrounding non-peatland conditions, and confirms the paleoenvironmental potential of leaf wax ratios on the peat sequences.

关键词： habitat n-Alkane compound specific carbon isotope compound specific hydrogen isotope peat deposit

Distribution characteristics and source tracing of petroleum hydrocarbons in the northeastern South China Sea

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Chinese Chemical Letters 2020年第10期31卷 2854-2858页

作者： Shengying Gong Wenhu Liu Yazhuo Li Jibiao Zhang Changlin Chen Jie Fu Department of Environmental Science and Engineering Fudan UniversityShanghai 200433China School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China Innovation Center of Ocean and Atmosphere System Zhuhai Fudan Innovation Research InstituteZhuhai 518057China

In recent years,oil spills caused by human activities have occurred frequently,and the resultant oil pollution has received extensive attention worldwide.In this paper,a total of 50 water samples were collected from the northeastern part of the South China Sea,and total petroleum hydrocarbons(TPHs)and n-Alkane content in the samples were analyzed by gas chromatography-flame ionization detector(GC-FID)technology.The petroleum hydrocarbon characteristic indices,such as carbon predominance index(CPI)and terrigenous/aquatic ratio(TAR),were calculated to trace the source of petroleum hydrocarbons.The measured value of TPHs ranged from 121.31-603.02μg/L.For surface waters,the TPHs in the no rthern coastal waters and the central waters were higher than that in the far shore.For ve rtical waters,the TPHs sharply decreased at first,and then increased slowly and finally reached a steady state.The n-Alkanes in the water samples were concentrated in C10-C38,and they were mainly from terrestrial higher plant.The waters in the near shore,mid-layer and deep sea showed a strong reducing terrestrial characteristic,while the surface waters in the open sea showed an obvious oxidizing endogenous characteristic.

关键词： Petroleum hydrocarbons South China Sea Oil spill n-Alkane Source tracing

Composition and Evolution of Hydrogen Isotopes of n-Akanes Generated from Anhydrous Pyrolysis of Sediments from Lake Gahai,Gannan,China

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Acta Geologica Sinica(English Edition) 2021年第5期95卷 1725-1735页

作者： DUAn Yi WU Yingzhong XInG Lantian LI Zhongping ZHAnG Ting northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences and Gansu Provincial Key Laboratory of Petroleum ResourcesLanzhou 730000China School of Earth Science&Resources Chang’an UniversityXi’an 710054China Shaanxi Center of Mineral Geological Survey Xi'an 710068China

To understand the thermal evolution of lacustrine sedimentary n-Alkane hydrogen isotopic composition(δD),especially bacterially derived n-Alkanes,anhydrous thermal simulation experiments were performed with sediments from Lake Gahai(Gannan,China).We analyzed the original and pyrolysis-generated n-Alkanes and theirδD values.The results showed that thermal maturity and n-Alkane origins significantly affected the distribution of pyrolysis-generated n-Alkanes.In immature to post-mature sediments,the bacterial-derived medium-chain n-Alkanes generally had depletedδD values.The maximum difference in averageδD values between the bacterial-and herbaceous plant-derived medium-chain n-Alkanes was 32‰,and the maximum difference in δD values among individual n-Alkanes was 59‰.We found that the averageδD value of pyrolysis-generated n-Alkanes from different latitude was significantly different in immature to highly mature sediments,but similar in post-mature ssediments.The hydrogen isotopes of sedimentary n-Alkanes can be used as indicators for paleoclimate/paleo-environment conditions only when sediments are immature to highly mature.During thermal evolution,the δD value of generated individual n-Alkanes and the averageδD value increased with thermal maturity,indicating that hydrogen isotopes of sedimentary n-Alkanes can be used as an index of organic matter maturity.We established mathematical models of average δD values of generated n-Alkanes from immature to post-mature sediments using n C_(21)^(-)/nC_(21)^(+)and average chain lengths.These results improve our understanding of the distribution andδD value of sedimentary n-Alkanes derived from herbaceous plants in mid-latitude plateau cold regions.

关键词： freshwater lake sediment n-Alkane simulation experiment bacterial origin hydrogen isotope thermal evolution

Paleohydrological Changes in the Western Tibetan Plateau over the Past 16,000 years Based on Sedimentary Records of n-Alkanes and Grain Size

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Acta Geologica Sinica(English Edition) 2020年第3期94卷 707-716页

作者： WAnG Mingda YAnG Yaping ZHAnG Jiawu HOU Juzhi Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Western China’s Environmental System(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China

Both monsoons and westerlies have exerted influence on climate dynamics over the Tibetan Plateau(TP) since the last deglaciation, producing complex patterns of paleohydroclimatic conditions. Diverse proxy records are essential to forge a robust understanding of the climate system on the TP. Currently, there is a general lack of understanding of the response of inland lakes over the TP to climate change, especially glacier-fed lakes. Paleohydrological reconstructions of such lakes could deepen our understanding of the history of lake systems and their relationship to regional climate variability. Here we use records of n-Alkanes and grain size from the sediments of Bangong Co in the western TP to reconstruct paleohydrological changes over the past 16,000 years. The Paq record(the ratio of non-emergent aquatic macrophytes versus emergent aquatic macrophytes and terrestrial plants) is generally consistent with the variations in summer temperature and precipitation isotopes. The changes in grain-size distributions show a similar trend to Paq but with less pronounced fluctuations in the early-middle Holocene. The new data combined with previous results from the site demonstrate that: 1) Bangong Co experienced relatively large water-level fluctuations during the last deglaciation, with a steadily high lake-level during the early-middle Holocene and a decreasing lake-level in the late Holocene;2) The lake level fluctuations were driven by both high summer temperatures via the melting water and monsoon precipitation. However, the dominant factor controlling lake level changed over time. The lake-level history at Bangong Co deduced from the n-Alkanes and grain-size records reveals the past hydrological changes in the catchment area, and stimulates more discussion about the future of glacier-fed lakes under the conditions of unprecedented warming in the region.

关键词： lake level n-Alkane Paq grain size Bangong Co Tibetan Plateau

Different patterns of molecular,carbon and hydrogen isotope compositions of n-Alkanes between heterotrophic plant and its hosts

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Frontiers of Earth Science 2020年第4期14卷 783-788页

作者： Xin Yang Xianyu Huang State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan430078China Hubei Key Laboratory of Critical Zone Evolution School of Geography and Information EngineeringChina University of GeosciencesWuhan430078China

This study investigates the molecular,carbon,and hydrogen isotope compositions of n-Alkanes in eight pairs of a holoparasitic plant(Cuscuta chinensis)and its hosts.It is unexpected that C.chinensis has a higher concentration of n-Alkanes than its hosts in seven of the eight pairs,and it is preferentially dominated by n-C_(29) alkane(representing>75%of the total n-Alkanes).In addition,theδ^(13)C values of C_(29) alkane in C.chinensis are less negative(avg.1.8‰)than those in the hosts,while theδ^(2)H values of C_(29) alkane are more negative in C.chinensis(the difference averages 48‰).We propose that the ^(2)H-depletion of n-Alkanes in the stem parasite C.chinensis may result from the utilization of stem water with less influence from evapotranspiration or the use of newly synthesized carbohydrates which is ^(2)H-depleted relative to stored sugars.These results highlight the importance of plant nutrient status on the molecular and isotopic compositions of leaf waxes,which shed light on the(paleo)ecological potential of leaf waxδ^(2)H values.

关键词： heterotrophic plant Cuscuta n-Alkane carbon isotope hydrogen isotope