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| 1 | Geochemistry of Two Types of Basalts in the Emeishan Basaltic Province: Evidence for Mantle Plume-Lithosphere Interaction显示文摘Based on the temporal-spatial distribution and geochemical characteristics, the Emeishan basalts can be divided into two types: high-P2O-TiO2 basalt (HPT) and low-P2O5-TiO2 basalt (LPT), which differ distinctly in geochemistry: the LPTs are characterized by relatively high abundances of MgO, total FeO and P2O5 and compatible elements (Cr, Ni, Sc), and relatively low contents of moderately compatible elements (V, Y, Yb, Co), LREE and other incompatible elements compared with the HPT. On the diagrams of trace element ratios, they are plotted on an approximately linear mixing line between depleted and enriched mantle sources, suggesting that these two types of basalts resulted from interactions of varying degrees between mantle plume and lithospheric mantle containing such volatile-rich minerals as amphibole and apatite. The source region of the LPT involves a smaller proportion of lithospheric components, while that of the HTP has a larger proportion of lithospheric components. Trachyte is generated by partial melting of the basic igneous rocks at the base of the lower continental crust. Both the two types of magmas underwent certain crystal fractionation and contamination of the lower crust at high-level magma chambers and en route to the surface. | ZHANG Zhaochong (张招崇) WANG Fusheng(王福生) | 2002 | Acta Geologica Sinica(English Edition)2002，76，2： | 31 |
| 2 | The migration fractionation: an important mechanism in the formation of condensate and waxy oil显示文摘Fault-initiated pressure release within reservoirs and the injection of external excessive dry gas may result in occurrence of oil and gas phases. Because of different partitioning coefficients of compounds in two phase flow, lower-molecular-weight components are easier to dissolve in gas phase, yielding condensates, while higher-molecular-weight components are retained in the oil phase, yielding waxy oil cumulations. The fractionation process causes extensive compositional variability in aliphatic/aromatic hydrocarbon ratios, molecular compound distributions and carbon isotope ratios that are traditionally considered to be related to the source organic matter or the thermal maturity. | ZHANG ShuichangKey Laboratory for Petroleum Geochemistry, China National Petroleum Corporation, Beijing 100083, China | 2000 | Chinese Science Bulletin2000，45，14： | 17 |
| 3 | 放射生物学概念在鼻咽癌、食管癌及肺癌治疗中的应用显示文摘The term 'altered factionation' is relative to the conventonal fractionation, which is defined as follows: for curative treatment of most cancers, 180 to 200 cGy per fraction is given once a day, 5 times per week, to a total dose determined by the tumor being treated and the tolerance of critical normal tissues within the target volume, usually 60 to 70 Gy within 6~7 weeks. The basic rationales for altered fractionation can be summaried by (1) The late-responding tissues are much more sensitive to fraction size than the early-responding tissues, with multiple smaller fractions. The late responding tissues can tolerate an increased total dose and the effects on the tumor therefore may be increased by the higher total radiation dose with improved tumor control; (2) Reduction in overall treatment time decreases the opportunity of accelerated regeneration of tumor cells during treatment and therefore inceases the probability of tumor control for a given total dose. In general,altered fractionation schemes can be categoriclly divided in to the following:(1) Hypofraction(2) Split-course radiation therapy(3) Hyperfractionation(4) Accelerated fractionation(5) Accelerated hyperfractionationIn recently years, we have tested various altered fractionation schedules for the treatment of nasopharyngeal, esophageal and lung cancer. For the nasopharyngeal caricnoma, hyperfractionation was used firstly by 1.1 Gy/F, 2F/day with an interval of >6hrs, followed by concomitant boost to a total dose of 74 Gy within 6 weeks. In lung cancer, the program was 1.15~1.25 Gy per fraction, two fractions per day for a total dose of 70 Gy with overall treatment time about 6 to 7 weeks. Esophageal cancer, conventional fractionation was given to total dose about 41 Gy followed by a boost for an additional 28 Gy by 1.5 Gy per fraction twice daily with overall treatment time about 6.3 weeks.Our preliminary treatment data showed that the local tumor control rates were higher in these study groups than the conventional groups and the acute reactions were increased as expected but tolerable. The main points of altered fractionation radiation schedules are also discussed. | 何少琴 | 1995 | 中华放射肿瘤学杂志1995，4，1： | 16 |
| 4 | Sequential fractionation of reactive phosphorus in the sediment of a shallow eutrophic lake——Donghu Lake, China显示文摘IntroductionSedimentphosphorushasbeenthefocusofanumberofstudiesduetoitsroleintheeutrophicationoflakes.Phosphorusfractionsinse?.. | FU Yong\|qing, ZHOU Yi\|yong\+*, LI Jian\|qiu (Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China) | 2000 | Journal of Environmental Sciences2000，12，1： | 15 |
| 5 | Field demonstration of reduction of lead availability in soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings using phosphorus fertilizers显示文摘A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate (SSP), phosphate rock (PR), and calcium magnesium phosphate (CMP) significantly decreased the percentage of water-soluble and exchangeable (WE) soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control (CK). The results showed that the level of 300 g P/m2 soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil de- creased by three phosphorus fertilizers followed the order: CMP (79%)>SSP (41%)>PR (23%); Effectiveness on the reduction of Pb uptake by cabbage was in the order: CMP (53%)>SSP (41%)>PR (30%). Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment. | 谢正苗 王碧玲 孙叶芳 李静 | 2006 | Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)2006，7，1： | 11 |
| 6 | Au-Sb association and fractionation in micro-disseminatedgold deposits, southwestern Guizhou——geochemistry andthermodynamics显示文摘The dual geochemical character of paragenesis and fractionation between gold, arsenic and antimony in micro-disseminated gold deposits in southwestern Guizhou is discussed in terms of spatial distribution of independent deposits, lateral and vertical enrichment, mineralization stage and factor and correlation analyses. Thermodynamic calculations of solubility and speciation of gold and antimony minerals indicate that gold is transported in hydrothermal solution as Au(HS) 2and antimony is mainly as Sb(OH)30 although HSb2S4 may be of increasing importance in acidenvironment at low temperatures during the late stage of mineralization. Changes in physico-chemical conditions hold the key to the association and fractionation between gold and antimony. Gold and antimony response differently to physicochemical variations because they are distinct from each other in soluble speciation and mineral solubility, leading to precipitation at different times and localities during hydrothermal evolution. | 朱赖民 胡瑞忠 | 2000 | Science China Earth Sciences2000，43，2： | 9 |
| 7 | Geochemical fractionation of rare earth elements in lacustrine deposits from Qaidam Basin显示文摘Based on the concentration and distribution pattern analysis of the rare earth elements (REEs) at the Shell Bar section from Qaidam Basin, we studied the geochemical fractionations of REE in paleolake deposits and their paleo-environmental significance. Our results show that the REE concentration in AS (acid soluble) and AR (acid residual) fractions are 20.9 μg/g and 95.4 μg/g (except element Y) individually, showing a strong REE differentiation between AS and AR fractions. However, the two types of fractions (AS & AR) have similar REE distribution patterns, which are slightly rich in light earth rare elements (LREEs), with slightly right-tilting and negative Eu anomaly. The LREE of AR is richer than that of AS. There were no significant correlations between the REE in AS, AR and other proxies. It indicated that the lacustrine deposition had different material sources and experienced varying geochemical procedures. Correlation analysis between the REE and the content of fine grain-size (<4 μm) of the sediments, Rb/Sr ratio and Mn concentration showed high correlation coefficients. Our results demonstrated that the REE in acid soluble and residual fractions bear different environmental significances, which are strongly dependent on local environment. The REE of acid soluble fraction is closely related to the paleoclimatic changes in the lake catchment and the evolutionary processes of lake itself. Our results suggest that δCe and (La/Yb)n could be used as proxies of the reduction-oxidation conditions and furthermore the temperature change and the lake level fluctuations. Using these proxies, we reconstructed the paleoclimate and water level fluctuation history during the high lake level period lasting between 43.5 and 22.4 cal. ka BP. | ZHANG HuCai ZHANG WenXiang CHANG FengQin YANG LunQing LEI GuoLiang YANG MingSheng PU Yang LEI YangBin | 2009 | Science China Earth Sciences2009，52，11： | 9 |
| 8 | Boron isotopic fractionation in laboratory inorganic carbonate precipitation:Evidence for the incorpora-tion of B(OH)_3 into carbonate显示文摘A laboratory inorganic carbonate precipitation experiment at high pH of 8.96 to 9.34 was conducted, and the boron isotopic fractionations of the precipitated carbonate were measured. The data show that boron isotopic fractionation factors (αcarb-3) between carbonate and B(OH)3 in seawater range 0.937 and 0.965, with an average value of 0.953. Our results together with those reported by Sanyal and collabo-rators show that the αcarb-3 values between carbonate and B(OH)3 in solution are not constant but are negatively correlated with the pH of seawater. The measured boron isotopic compositions of carbonate precipitation (δ11Bcarb) do not exactly lie on the best-fit theoretical δ 11B4-pH curves and neither do they exactly parallel any theoretical δ 11B4-pH curves. Therefore, it is reasonable to argue that a changeable proportion of B(OH)3 with pH of seawater should also be incorporated into carbonate except for the dominant incorporation of B(OH)4- in carbonate . Hence, in the reconstruction of the paleo-pH of sea-water from boron isotopes in marine biogenic carbonates, the use of theoretical boron isotopic frac-tionation factor (α4-3) between B(OH)4- and B(OH)3 is not suitable. Instead, an empirical equation should be established. | XIAO YingKai1,2, LI HuaLing1,3, LIU WeiGuo4, WANG XiuFang1 & JIANG ShaoYong5 1 Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 2 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 3 Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China 4 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China 5 State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China | 2008 | Science China Earth Sciences2008，51，12： | 8 |
| 9 | Speciation of organic phosphorus in a sediment profile of Lake Taihu I:Chemical forms and their transformation显示文摘Organic phosphorus(nonreactive P,NRP)is a major component of P in sediments,but information about its chemical forms and dynamic transformation is limited.The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu,a freshwater and eutrophic lake in China,were investigated.Five forms of NRP in the sediments were extracted based on a chemical fractionation technique,including easily labile NRP(NaHCO3-NRP),reactive metal oxide-bound NRP(HCl-NRP),humic acid-associated NRP(NaOH-NRPHA),fulvic acid-associated NRP(NaOH-NRPFA)and residual NRP(Res-TP).There were notable transformations with increasing sediment depth from the labile NaHCO3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools,which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded.Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP.The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments. | Di Xu Shiming Ding Bin Li Xiuling Bai Chengxin Fan Chaosheng Zhang | 2013 | Journal of Environmental Sciences2013，25，4： | 7 |
| 10 | Insight into removal of dissolved organic matter in post pharmaceutical wastewater by coagulation-UV/H_2O_2显示文摘The removal of four dissolved organic matter(DOM) fractions, non-acid hydrophobics,hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H_2O_2 oxidation in post-pharmaceutical wastewater(PhW W). Coagulation with Polyferric chloride(PFC), Polymeric ferric sulfate(PFS) and Polymeric aluminum ferric chloride(PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H_2O_2 oxidation method resulted in much higher reduction rates for dissolved organic carbon(DOC)(by 75%) and UV_(254)(by 92%) than coagulation or UV/H_2O_2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%,70% and 39%, respectively. Parallel factor analysis(PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal(by 44%)during the coagulation stage. After coagulation-UV/H_2O_2 treatment, the humic-like fluorescent component C3 had the highest removal(by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations(R2> 0.8)between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H_2O_2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhW W decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52. | Feng Qian Mengchang He Jieyun Wu Huibing Yu Liang Duan | 2019 | Journal of Environmental Sciences2019，31，2： | 7 |
| 11 | REE Geochemistry in the Weathered Crust of Granites, Longnan Area,Jiangxi Province显示文摘Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks. | Wu Chengyu Huang Dianhao Guo Zhongxun Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing Geological Survey Party of South Jiangxi, Jiangxi Bureau of Geology and Mineral Resources, Ganzhou, Jiangxi | 1990 | Acta Geologica Sinica(English Edition)1990，64，2： | 7 |
| 12 | Soil organic carbon associated with aggregate-size and density fractions in a Mollisol amended with charred and uncharred maize straw显示文摘Straw return has been strongly recommended in China,whereas applying biochar into soil is considered to provide more benefits for agriculture as well as the environment.In this study,a five-year(2011-2015) field experiment was conducted to evaluate the effects of uncharred maize straw amendment(MS) and charred maize straw amendment(charred MS) on organic carbon(C) contents in bulk soil and in various soil aggregate-size and density fractions.Compared to no amendment(CK),the bulk soil organic C content significantly improved by 9.30% for MS and by 23.4% for charred MS.Uncharred and charred maize straw applied annually at a consistent equal-C dosage resulted in 19.7 and 58.2% organic C sequestration efficiency in soil,respectively,after the five years of the field experiment.The percentages of macroaggregates(>0.25 mm) and occluded microaggregates(0.25-0.053 mm) obviously increased by 7.73 and 18.1% for MS and by 10.7 and 19.6% for charred MS,respectively.Moreover,significant incremental increases of 19.4 and 35.0% in macroaggregate-associated organic C occurred in MS and charred MS,respectively.The occluded microaggregates associated organic C significantly increased by 21.7% for MS and 25.1% for charred MS.Mineral-associated organic C(<0.053 mm) inside the macroaggregates and the occluded microaggregates obviously improved by 24.7 and 33.3% for MS and by 18.4 and 44.9% for charred MS.Organic C associated with coarse particulate organic matter(POM) within the macroaggregates markedly increased by 65.1 and 41.2% for MS and charred MS,respectively.Charred MS resulted in a noteworthy increment of 50.4% for organic C associated with heavy POM inside the occluded microaggregates,whereas charred MS and MS observably improved organic C associated with heavy POM inside the free microaggregates by 36.3 and 20.0%,respectively.These results demonstrate that uncharred and charred maize straw amendments improve C sequestration by physically protecting more organic C in the macroaggregates and the occluded microaggregates.Compared to the feedstock straw amendment,charred maize straw amendment is more advantageous to C sequestration. | GUAN Song LIU Si-jia LIU Ri-yue ZHANG Jin-jing REN Jun CAI Hong-guang LIN Xin-xin | 2019 | Journal of Integrative Agriculture2019，18，7： | 7 |
| 13 | Mantle heterogeneity,plume-lithosphere interaction at rift controlled ocean-continent transition zone:Evidence from trace-PGE geochemistry of Vempalle flows,Cuddapah Basin,India显示文摘This study reports major, trace, rare earth and platinum group element compositions of lava flows from the Vempalle Formation of Cuddapah Basin through an integrated petrological and geochemical approach to address mantle conditions, magma generation processes and tectonic regimes involved in their formation. Six flows have been identified on the basis of morphological features and systematic three-tier arrangement of vesicular-entablature-colonnade zones. Petrographically, the studied flows are porphyritic basalts with plagioclase and clinopyroxene representing dominant phenocrystal phases.Major and trace element characteristics reflect moderate magmatic differentiation and fractional crystallization of tholeiitic magmas. Chondrite-normalized REE patterns corroborate pronounced LREE/HREE fractionation with LREE enrichment over MREE and HREE. Primitive mantle normalized trace element abundances are marked by LILE-LREE enrichment with relative HFSE depletion collectively conforming to intraplate magmatism with contributions from sub-continental lithospheric mantle(SCLM) and extensive melt-crust interaction. PGE compositions of Vempalle lavas attest to early sulphur-saturated nature of magmas with pronounced sulphide fractionation, while PPGE enrichment over IPGE and higher Pd/Ir ratios accord to the role of a metasomatized lithospheric mantle in the genesis of the lava flows. HFSEREE-PGE systematics invoke heterogeneous mantle sources comprising depleted asthenospheric MORB type components combined with plume type melts. HFSE-REE variations account for polybaric melting at variable depths ranging from garnet to spinel lherzolite compositional domains of mantle. Intraplate tectonic setting for the Vempalle flows with P-MORB affinity is further substantiated by(i) their origin from a rising mantle plume trapping depleted asthenospheric MORB mantle during ascent,(ii) interaction between plume-derived melts and SCLM,(iii) their rift-controlled intrabasinal emplacement through Archeane Proterozoic cratonic blocks in a subduction-unrelated ocean-continent transition zone(OCTZ). The present study is significant in light of the evolution of Cuddapah basin in the global tectonic framework in terms of its association with Antarctica, plume incubation, lithospheric melting and thinning, asthenospheric infiltration collectively affecting the rifted margin of eastern Dharwar Craton and serving as precursors to supercontinent disintegration. | Th.Dhanakumar Singh C.Manikyamba K.S.V.Subramanyam Sohini Ganguly Arubam C.Khelen N.Ramakrishna Reddy | 2018 | Geoscience Frontiers2018，9，6： | 6 |
| 14 | Petrogenesis and tectonic implications of Indosinian granitoids from Western Qinling Orogen,China:Products of magma-mixing and fractionation显示文摘The Western Qinling Orogen(WQO) is characterized by voluminous distribution of Indosinian granitoids,the formation of which provides an important window to unravel the geochemical and geodynamic evolution and associated metallogeny.Here we investigate a group of intrusions termed 'Five Golden Flowers' based on petrological,geochemical,zircon U-Pb geochronological and Lu-Hf isotopic studies on the granitoids and their mafic microgranular enclaves(MMEs).Our results show that these intrusions are genetically divided into two types,namely,magma-mixing and highly fractionated.The Jiaochangba,Lujing,Zhongchuan,and Luchuba granitoids are biotite monzogranites(220±0.8 Ma to 217±2.6 Ma) with abundant coeval MMEs(220±.1 Ma to 217±2.7 Ma).The rocks contain moderate to high SiO2,high MgO,Rb,Sr,Ba,and Th contents,but low TiO2,P2 O5,and Sc values,A/CNK of <1.1,and a range of εHf(t) values of-11.7 to +2.23 with corresponding TDM2values of 1967-1228 Ma.The MMEs possess K-feldspar megacrysts,abundant acicular apatites,and show lopsided textures.They have lower SiO2,Al2 O3,and Th contents,but higher MgO,TiO2,and Sc,with εHf(t) values of-18.0 to +3.18 and TDM1 of 849-720 Ma.The data indicate that the MMEs were derived from a magma sourced from the enriched lithospheric mantle.We suggest that these host granitoids were produced by partial melting of latePaleoproterozoic to early-Mesoproterozoic lower crust with the involvement of Neoproterozoic SCLM-derived mafic magmas.The Baijiazhuang pluton is dominantly composed of leucogranite(muscovite granite and twomica monzogranite,216±1.5 Ma) without MMEs.The rocks are peraluminous with high A/CNK(1.06-1.27).Compared with the other four granitoids,the Baijiazhuang leucogranite shows higher SiO2 content,markedly lower concentrations of TiO2,MgO,Al2 O3,CaO,and Fe2 O3T,and lower LREE/HREE and(La/Yb)N values.These leucogranites are also rich in Rb,Th,and U,and display marked depletions in Ba,Sr,Ti,and Eu,indicating that they experienced significant fractionation.Zircon εHf(t) values(-10.2 to-3.27) and TDM2(1868-1424 Ma),as well as the Nb/Ta and K2 O/Na2 O values are similar to the other four granitoids,indicating that they are likely to have been derived from a similar source;with sediments playing only a minor role in the magma generation.The low contents of Yb and Y suggest that their partial melting was controlled by garnets and micrographic texture of K-feldspar reflects high-temperature melting through undercooling.Based on the above features,we infer that the Baijiazhuang leucogranite likely represents the product of high degree fractionation of the I-type biotite monzogranite magma which generated the other four granitoids at relatively high temperatures,within magma chambers at mid-crust depths.We propose that the granitoid suite was formed in the transitional setting from synto post-collision during the collisional orogeny between the SCB and NCB,following break-off of the subducted South China Block lithosphere during 220-216 Ma. | Xiao Xiong Laimin Zhu Guowei Zhang M.Santosh Hang Jiang Jun Zheng Anlin Guo Lele Ding | 2020 | Geoscience Frontiers2020，11，4： | 6 |
| 15 | Abiogenic hydrocarbons in commercial gases from the Songliao Basin,China显示文摘This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha- nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode- gradation of complex high-molecule sedimentary organic material can form microbial gas or thermogenic gas. The δ 13C1 value ranges from -110‰ to -50‰ for microbial gases but from -50‰ to -35‰ (even heavier) for thermogenic gases. Controlled by the kinetic isotope fractionation, both microbial and thermogenic gases have δ 13C and δ D values characterized by normal distribution, i.e. δ 13C1< δ 13C2< δ 13C3< δ 13C4 and δ DCH4< δ DC2H6< δ DC3H8<δ DC4H10, and by a positive correlation between the δ 13C and δ D values. Simple carbonbearing molecules (CH4, CO and CO2) can form abiogenic alkane gases via polymerization in the abiological chemical process in nature, with δ 13C1 heavier than -30‰. Moreover, controlled by the kinetic isotope fractionation, abiogenic alkane gases are characterized by a reverse distribution of δ 13C values and a normal trend of δ D values, namely δ 13C1> δ 13C2> δ 13C3> δ 13C4 and δ DCH4<δ DC2H6< δ DC3H8< δ DC4H10. The δ 13C values and δ D values are negatively correlated. Natural gases from 26 commercial gas wells distributed in the Xujiaweizi and Yingshan-Miaotaizi faulted depressions in the Songliao Basin, China, show δ13C1 values ranging from -30.5‰ to -16.7‰ with a very narrow δ D range between -203‰―-196‰. These gases are characterized by a reverse distribution of δ 13C values but a normal distribution of δ D values, and a negative correlation between their δ 13C and δ D values, indicating an abiological origin. The present study has revealed that abiogenic hydrocarbons not only exist in nature but also can make significant contribution to commercial gas reserviors. It is estimated that the reserve volume of alkane gases with abiogenic characteristics in these 26 gas wells in the Songliao Basin is over 500×108 m3. The prospecting practice in the Songliao Basin has demonstrated that abiogenic alkane gases are of a promising resource, and it provides an example for the investigation of and search for abiogenic commercial natural gases worldwide. | WANG XianBin GUO ZhanQian TUO JinCai GUO HongYan LI ZhenXi ZHUO ShengGuang JIANG HongLiang ZENG LongWei ZHANG MingJie WANG LianSheng LIU ChunXue YAN Hong LI LiWu ZHOU XiaoFeng WANG YongLi YANG Hui WANG Guang | 2009 | Science China Earth Sciences2009，52，2： | 6 |
| 16 | MATHEMATICAL MODELING OF VARIATIONS ON STABLE ISOTOPIC RATIOS IN FALLING RAINDROPS显示文摘The variations of stable isotopic contents in falling raindrops are not only influenced by thehumidity conditions, but also by the stable isotopic contents in atmospheric vapor to a certainextent. If there is a difference between the isotopic contents in the vapor of the surrounding air andat the surface of the raindrops, the move of the isotopic contents from high to low values will beproduced. Usually. influenced by the evaporation process, the stable isotopic ratios in raindropsare constantly increased in the unsaturated atmosphere. The less the atmospheric humidity, themore obvious the increased range. As the enrichment rate of stable isotopes in raindrops is equal tothe outward isotopic move rate. the 'pseudo-equilibrium state' appears. The influence ofevaporation on stable isotopic contents disappears in the saturated atmosphere, so that themagnitude of isotopic ratio in raindrops is dependent on the isotopic exchange between theraindrops and the surrounding atmosphere. | 章新平 谢自楚 姚檀栋 | 1998 | Acta meteorologica Sinica1998，12，2： | 4 |
| 17 | Fractionations of rare earth elements in plants and their conceptive model显示文摘Fractionations of rare earth elements (REEs) and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions. Significant enrichment of middle REEs (MREEs) and heavy REEs (HREEs) was observed in plant roots and leaves respectively, with slight fractionation between light REEs (LREEs) and HREEs in stems. Moreover, the tetrad effect was observed in these organs. Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy (XAS) and nanometer-sized TiO2 adsorption techniques, associated with other controlled experiments, demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation, and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands. A conceptive model was established for REE fractionations in plants based on the above studies. | DING ShiMing1,2, LIANG Tao2, YAN JunCai3, ZHANG ZiLi3, HUANG ZeChun2 & XIE YaNing4 1 Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008, China 2 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 3 Anhui Agricultural University, Hefei 230036, China 4 State Key Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China | 2007 | Science China(Life Sciences)2007，50，1： | 4 |
| 18 | Carbon isotope fractionation during shale gas transport: Mechanism, characterization and significance显示文摘The gas in-place(GIP)content and the ratio of adsorbed/free gas are two key parameters for the assessment of shale gas resources and have thus received extensive attention.A variety of methods have been proposed to solve these issues,however none have gained widespread acceptance.Carbon isotope fractionation during the methane transport process provides abundant information,serving as an effective method for differentiating the gas transport processes of adsorbed gas and free gas and ultimately evaluating the two key parameters.In this study,four stages of methane carbon isotope fractionation were documented during a laboratory experiment that simulated gas transport through shale.The four stages reflect different transport processes:the free gas seepage stage(Ⅰ),transition stage(Ⅱ),adsorbed gas desorption stage(Ⅲ)and concentration diffusion stage(Ⅳ).Combined with the results of decoupling experiments,the isotope fractionation characteristics donated by the single effect(seepage,adsorption-desorption and diffusion)were clearly revealed.We further propose a technique integrating the Amoco curve fit(ACF)method and carbon isotope fractionation(CIF)to determine the dynamic change in adsorbed and free gas ratios during gas production.We find that the gases produced in stage Ⅰ are primarily composed of free gas and that carbon isotope ratios of methane(δ13C1)are stable and equal to the ratios of source gas(13C 10).In stage Ⅱ,the contribution of free gas decreases,while the proportion of adsorbed gas increases,and the δ13C1 gradually becomes lighter.With the depletion of free gas,the adsorbed gas contribution in stage Ⅲ reaches 100%,and the δ13C1 becomes heavier.Finally,in stage Ⅳ,the desorbed gas remaining in the pore spaces diffuses out under the concentration difference,and the δ13C1 becomes lighter again and finally stabilizes.In addition,a kinetic model for the quantitative description of isotope fractionation during desorption and diffusion was established. | Wenbiao LI Shuangfang LU Junqian LI Pengfei ZHANG Siyuan WANG Wenjun FENG Yongbo WEI | 2020 | Science China Earth Sciences2020，63，5： | 4 |
| 19 | Crucial control on magmatic-hydrothermal Sn deposit in the Tengchong block,SW China:Evidence from magma differentiation and zircon geochemistry显示文摘Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hydrothermal Sn mineralization,including advanced fractionation and depressurization-induced rapid cooling,were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit,in the Tengchong block,SW China.The Guyong granitic pluton comprises three petrological facies:less evolved biotite syenogranite,evolved alkali granite and leucogranite,and highly evolved facies(the protolith of greisenized granite).Similar crystallization ages(~77 Ma)and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process.Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high(>87 wt.%)that can only be achieved by a high initial water(≥4 wt.%)content in the parent granitic magma revealed by rhyolite-MELTS calculation.Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas,suppressing the exsolution and transport of hydrothermal fluids.Hence,it must be compensated by the second critical factor:depressurization-induced rapid cooling,reflected by the occurrence of highly metamict zircons in the greisenized granite.The highly metamict feature,indicated by the large full width at half maximum(FWHM)values of zirconν3(SiO_(4)) peak(>19.5 cm^(-1)),suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment.Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids,interacting with wall rocks and resulting in Sn mineralization. | Qiwei Zhang Qingfei Wang Gongjian Li Xiang Sun Qihai Shu Jun Deng | 2022 | Geoscience Frontiers2022，13，4： | 4 |
| 20 | Reconstruction the Process of Partial Melting of the Retrograde Eclogite from the North Qaidam,Western China: Constraints from Titanite U-Pb Dating and Mineral Chemistry显示文摘Retrograde eclogite and garnet amphibolite of the Lüliangshan unit of the Shenglikou area,North Qaidam,were studied with emphasis on rutile and titanite.A special focus is on the formation of rutile and its corona of titanite(Ttn1)in retrograde eclogite and on coarse-grained titanite(Ttn2)from the garnet amphibolite.Using zirconium(Zr)-in-rutile and Zr-in-titanite thermometers,the temperatures estimated for the formation of an early generation of rutile are 823–884℃at 2.5–2.8 GPa,while 812–894℃at 1.3–1.5 GPa are derived for the formation of coronitic Ttn1 in the retrograde eclogite.Therefore,isothermal decompression must have occurred during exhumation,which also has triggered the partial melting of the retrograde eclogite.Ttn2 of the garnet amphibolite has high REE contents and high Th/U ratios,indicating that it is newly grown from a Ti,Ca,and LREE enriched anatectic melt derived from the partial melting of retrograde eclogite.LA-ICP MS U-Pb dating yields a lower intercept age of 423±4 Ma for Ttn2,which is consistent with the granulite-facies metamorphic age of the retrograde eclogite.Moreover,a temperature of 781–823℃at 1.0–1.2 GPa is obtained for Ttn2,which fits the P-T conditions of the HP granulite-facies metamorphic stage(P=1.07–1.24 GPa and T=774–814℃),and documents that the crystallization of the melt occurred at the granulite-facies stage at 423 Ma.The high amount of REE of the garnet amphibolite is a consequence of the formation of Ttn2 from the melt.The contents and ratios of Zr and Hf in rutile and Ttn2 differ from those in the garnet amphibolite,and the whole rock Zr/Hf ratios of retrograde eclogite and garnet amphibolite are both higher than the respective ratios in rutile and Ttn2,suggesting that rutile and titanite cannot be the major carriers of Zr and Hf accounting for the high whole rock Zr/Hf ratios. | Yuting Cao Liang Liu Wenqiang Yang Yuan Gao Xiaohui Zhu | 2019 | Journal of Earth Science2019，30，6： | 4 |
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