According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classificatio...According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classification of crude oils in the Tazhong area of the Tarim Basin, China. Crude oils from the area studied are classified as three genetic types: type-I is characterized by the low contents of C29 norhopane, extremely abundant contents of gammacerane, low contents of rearranged sterane and relatively high contents of regular C28 sterane; the geochemical properties of type-II crude oils are opposite to those of type-I crude oils; the parameters for type-III crude oils are intermediate between type-I and type-II. Results of oil correlation indicated that type-I crude oils were derived from Cambrian-Lower Ordovician hydrocarbon source rocks, type-II curde oils originated from Middle-Upper Ordovician hydrocarbon source rocks and type-III crude oils are of mixed origin.展开更多
Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic ...Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and assessments on the environmental geochemistry and ecological risk of vanadium in the Panzhihua mining and smelting area. In the study area, anthropogenic vanadium resulted from mining, extracting and smelting of V-Ti magnetite; vanadium pollution of topsoil and sediments occurs mainly in the mining and extracting area, smelting area, slag dumping area, tailing dam and coal mining area. In the soil, the chemical speciation of vanadium shows: insoluble residue > organically bound > Fe (amorphous) oxide-bound > Mn oxide-bound > soluble component. Vanadium pollution can cause potential harmful effects on ecological systems, and lead to animal poisoning and human disease. So vanadiam pollution should be monitored on a regular basis in the Panzhihua area.展开更多
The geochemical characteristics of crude oils and reservoir core extracts from the Kuche petroleum system are described and studied systematically by means of various geochemical techniques and methods to acquire mole...The geochemical characteristics of crude oils and reservoir core extracts from the Kuche petroleum system are described and studied systematically by means of various geochemical techniques and methods to acquire molecular information. The results suggest crude oils from the petroleum system can be divided into two groups: marine oils and non-marine oils. The former represents the dominant oils found in the area. Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs, with Lower Tertiary sandstone reservoirs in the Yaha oilfield of the Tarim Basin. However, based on the ratio of 20S/(20S+20R)C-29 sterane as a maturity parameter, lacustrine oils filled into the Tertiary reservoirs in the direction toward the western part of the petroleum system. In contrast, according to the fact that methylcyclohexane indices of eastern oils are greater than those of western oils, the location in which coal-generated oils filled into the Tertiary reservoirs lies in the eastern part of the petroleum system.展开更多
Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin...Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin, Xinjiang, China, showed that even though there are quite a number of factors affecting the distributional and compositional characteristics of neutral nitrogen-containing compounds in crude oils, the distributional and compositional characteristics of crude oils whose source conditions are approximate to one another are influenced mainly by the migration and fractionation effects in the process of formation of oil reservoirs. In addition, crude oils in the Tazhong region show obvious migration-fractionation effects in the vertical direction. Carboniferous crude oils are characterized by high migration parameters and low compound concentrations, just in contrast to Ordovician crude oils. This indicates that crude oils from shallow-level oil reservoirs were derived from those of deep-level oil reservoirs via faults, unconformable contact or carrier beds. Crude oils from the Tazhong region show some migration-fractionation effects in the lateral direction, but mixing of crude oils derived from different hydrocarbon source rocks in the process of formation of oil reservoirs made it more complicated the migration and accumulation of crude oils, as well as the formation of oil reservoirs.展开更多
The plane tree, which is a valuable tool to detect atmospheric pollution, is one of the most common trees in European cities. Soil and leaf samplings were carried out in Barcelona and its environs (NE Spain) to establ...The plane tree, which is a valuable tool to detect atmospheric pollution, is one of the most common trees in European cities. Soil and leaf samplings were carried out in Barcelona and its environs (NE Spain) to establish the soil-plant relationship. Dry and ashed leaves and soils were analyzed by Instrumental Neutron Activation Analysis and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP/OES) at the ACTLABS laboratories in Ontario, Canada. Given that diesel is the main fuel used in vehicles in Europe, we sought to establish the role of diesel in atmospheric pollution. Diesel samples were obtained from service stations and analyzed after preconcentration using ICP/MS at the geochemistry laboratories of the University of Barcelona. The average content of diesel oil shows high values of Pb, Cu, Cr, Ag, Cd and Mn. High values of Pb, Cu, Au, Hg and Sb in leaves and soils were detected downtown and along main roads outside the city, whereas low levels of these elements were observed in rural areas.展开更多
Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show t...Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show that the crude oils have even-odd carbon predominance for n-alkanes.In shallow reservoir,part of crude oils suffered biogenic degradation.As for normal oils,they have low Pr/Ph ratios with abundant gammacerane and C35 homohopane,which indicate that the crude oils are formed in strong reducing salt water environment.Compared deep(E13) reservoir with shallow(N1-N12) reservoir,the ancient salinity of sedimentary environment of N1--N12 crude oils is slightly higher than that of E13 crude oils;the C-21/C+22 ratios of crude oils are 1.02-1.71 with a higher abundance of C27 sterane,which shows that their mainly origin matrix are bacteria and algae;the C29 sterane 20S/(20S+20R)is generally low,the ratio in deep E13 reservoir distributes between 0.31 and 0.40,but in shallow reservoir is relatively low with 0.29-0.36.At the same time,C29 sterane αββ/(αββ+ααα)and Ts/Tm both are extremely lower.All the above show that the crude oils in Gas Hure are mainly low mature oils,although the maturity of deep reservoir crude oils is slightly higher than shallow one.展开更多
Based on the systematic study of aromatic hydrocarbons in over 100 crude oil samples collected from the Tabei and Tazhong uplifts in the Tarim Basin,the western depression area in the Qaidam Basin and the Tabei depres...Based on the systematic study of aromatic hydrocarbons in over 100 crude oil samples collected from the Tabei and Tazhong uplifts in the Tarim Basin,the western depression area in the Qaidam Basin and the Tabei depression in the Turpan Basin,the geochemical characteristics of the marine(Tarim Basin),saline lacustrine(Qaidam Basin),and swamp(Turpan Basin) oils were investigated.The marine oils from the Tarim basin are characterized by relatively low abundance of diaromatic hydrocarbons such as biphenyl and naphthalene,and relatively high abundance of triaromatic hydrocarbons including phenanthrene,dibenzothiophene and fluorene.In contrast,the swamp oils from the Turpan Basin are dominated by the highest relative abundance of diaromatic hydrocarbons and the lowest relative abundance of triaromatic hydrocarbons in all the oil samples in this study.The relative abundance of diaromatic and triaromatic hydrocarbons in the saline lacustrine oils from Qaidam Basin is between that in Tarim oils and Turpan oils.Aromatic parameters based on the isomer distributions of dimethylnaphthalenes(DMN),trimethylnaphthalenes(TMN),tetramethylnaphthalenes(TeMN) and methylphenanthrenes(MP),i.e.,1,2,5-trimethylnaphthalene(TMN)/1,3,6-TMN ratio,1,2,7-TMN/1,3,7TMN ratio,(2,6-+2,7-)-dimethylnaphthalenes(DMN)/1,6-DMN ratio,1,3,7-TMN/(1,2,5-+1,3,7-)TMN,1,3,6,7-TeMN/(1,3,6,7-+1,2,5,6-+1,2,3,5-)-TeMN ratio and MP index,may reflect the diversity of organic source input,thermal maturity and depositional environments.In addition,the dibenzothiophenes(DBTs)/fluorenes(Fs) and dibenzofurans(DBFs)/Fs ratios were found to the very useful and effective in determining genetic types of crude oils for the marine,saline lacustrine,and swamp depositional environments,and for oil-oil correlations.展开更多
This paper dealt with the Pb contents and Pb isotopic composition of the West Lake Longjing tea. The results showed that in the tea leaves, from young leaf →old leaf →tea limb, the Pb contents tend to increase gradu...This paper dealt with the Pb contents and Pb isotopic composition of the West Lake Longjing tea. The results showed that in the tea leaves, from young leaf →old leaf →tea limb, the Pb contents tend to increase gradu-ally from 1.63 →4.84 →6.07×10-6, wich revealed that the Pb was accumulated gradually in the tea. After cleaned, the Pb contents of tea leaves were significantly reduced. This indicated that the deposits on the surface of tea leaves made a great contributuion to Pb contents. The survey results for soils in the relevant tea gardens showed that soil from the Longjing tea garden has higher Pb contents, with an average level of 49.6×10-6, two times those of common soils (24×10-6) in China. Results of the systematic analysis for tea, tea garden soil and the samples with the relevant background of the Pb isotopic composition displayed that the Pb isotopic ratio of tea is 206Pb/207Pb=1.164±0.005 (2σ). The ratio of 206Pb/207Pb for the soil gradually decreased from residue phase, soil dilute acid extract phase, and then to urban topsoil, i.e., 1.175 →1.171 →1.170. The 208Pb/(206Pb+207Pb) ratios also show a similar variation trend. 206Pb/207Pb ratios in the samples with the relevant background were: vehicle exhaust, 1.124; coal-combustion, 1.156; atmosphere, 1.168; and water, 1.166. Comparative studies have shown that Pb pollution is popular in the environ-mental media (soil, atmosphere, water) in Hangzhou. With the aggravation of Pb pollution, the Pb isotopic composi-tion gradually changed from the natural background (soil residues) to the direction of automobile exhaust. This phe-nomenon could illustrate that the pollution source was the vehicle exhaust, while the coal-combustion contributed little to environmental pollution in Hangzhou. The Pb of the Longjing tea came mostly from soluble phase Pb in the polluted soil. Moreover, secondary pollution was caused by vehicle exhaust.展开更多
Whole rock major and trace element geochemistry together with zircon U-Pb ages and Sr-Nd isotope compositions for the Middle Eocene intrusive rocks in the Haji Abad region are presented. The granitoid hosts, including...Whole rock major and trace element geochemistry together with zircon U-Pb ages and Sr-Nd isotope compositions for the Middle Eocene intrusive rocks in the Haji Abad region are presented. The granitoid hosts, including granodiorite and diorite, yielded zircon U-Pb ages with a weighted mean value of 40.0 ± 0.7 Ma for the granodiorite phase. Mafic microgranular enclaves(MMEs) are common in these plutons, and have relatively low SiO_2 contents(53.04-57.08 wt.%) and high Mg#(42.6-60.1), probably reflecting a mantle-derived origin. The host rocks are metaluminous(A/CNK = 0.69-1.03), arc-related calc-alkaline, and I-type in composition, possessing higher SiO_2 contents(59.7-66.77 wt.%) and lower Mg#(38.6-52.2); they are considered a product of partial melting of the mafic lower crust. Chondritenormalized REE patterns of the MMEs and granitoid hosts are characterized by LREE enrichment and show slight negative Eu anomalies(Eu/Eu* = 0.60-0.93). The host granodiorite samples yield(^(87)Sr/^(86)Sr);ratios ranging from 0.70498 to 0.70591,positive eNd(t) values varying from +0.21 to +2.3, and TDM2 ranging from 760 to 909 Ma, which is consistent with that of associated mafic microgranular enclaves(^(87)Sr/^(86)Sr)i = 0.705111-0.705113, ε_(Nd)(t)= +2.14 to +2.16, T_(DM2) = 697-785 Ma). Petrographic and geochemical characterization together with bulk rock Nd-Sr isotopic data suggest that host rocks and associated enclaves originated by interaction between basaltic lower crust-derived felsic and mantlederived mafic magmas in an active continental margin arc environment.展开更多
In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan p...In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan pro- file, which is located in Chaoxian County, south of Anhui Province, are described in the light of gas chromatogra- phy/mass spectrometric (GCMS) analysis on the qualitative and quantitative basis. Based on the investigation of the biomarker assemblage characteristics of possible source rocks developed in the area studied, a conclusion is drawn that the oilshow was generated from the Nanlinghu Formation source rocks (abbreviated as T1n), instead of the Qixia Formation source rocks (abbreviated as P1q). It is pointed out that the T1n is of strong potential for future oil explora- tion, and therefore much attention should be paid to it.展开更多
Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used ...Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used successfully in such cases that conventional production logging techniques are powerless. Taking low-concentration anthracene as internal standard, we calculated the absolute concentrations!of fingerprints, initially made some experiments directly on biodegradation of crude oils, and calculated production allocation in the Gudong Oil field. Compared with the production logging, this method has made up for the deficiencies of the former GC fingerprint technique. It will find wide applications in monitoring the trend of production in various oil-fields.展开更多
Terrestrial faulted lacustrine basin is considered as a favorable place for the development of source rocks,especially the fault basins in eastern China.Based on molecular composition study of saturated and aromatic h...Terrestrial faulted lacustrine basin is considered as a favorable place for the development of source rocks,especially the fault basins in eastern China.Based on molecular composition study of saturated and aromatic hydrocarbons in the extracts of source rocks of the Yingcheng and Shahezi formations in the Lishu Fault Depression,it is revealed that the extracts of source rocks are provided with low ratio of Pr/Ph,low content of C24 tetracyclic terpanes,high content of tricyclic terpanes and gammacerane,relatively high content of C27 steranes in the sag belt and its periphery;relatively high ratio of Pr/Ph,relatively high content of tetracyclic terpanes and gammacerane,low content of C27 steranes and obvious advantages of C29 steranes in its gentle slope belt;with high ratio of Pr/Ph,high content of C19,C20 tricyclic and C24 tetracyclic terpanes,very low content of gammacerane and C27 steranes,and high content of C29 steranes in the edge of fault depression.According to the organic matter input and sedimentary environment,three types of source rocks have been established,which,respectively,are the mode of mixing organic matter input in deep and semi-deep lake,the advantage of terrigenous input in shallow lake and terrigenous input in shore-shallow lacustrine.The first mode is supposed to generate oil and gas,while the second one tends to generate oil.The distribution characteristics of oil and gas in the Lishu Fault Depression are very likely to be controlled by hydrocarbon generating characteristic of different source rock types.展开更多
Light hydrocarbons, especially C-7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K-1 values [(2-MH+2,3-DMP)/(3-MH+2,4-DMP...Light hydrocarbons, especially C-7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K-1 values [(2-MH+2,3-DMP)/(3-MH+2,4-DMP)] of crude oils vary from a lowest value of {0.78}, to a highest value of {1.54}, but the K-1 values of the majority of oil samples (80%) range from {0.90} to {1.20}. However, the absolute contents of (2-methylhexane+ 2,3-dimethylpentane) and (3-methylhexane+2,4-dimethylpentane) in the total light hydrocarbons (C-4-C-7) show a similar variation trend. The variation of K-1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C-7 light hydrocarbons in light of the steady-state catalytic hypothesis, non-marine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.展开更多
Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydro...Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydrocarbons in oils were studied systematically in this paper.Among those constitutes,naphthalene(43% 59%),phenanthrene(12% 21%) and taromatic-sterane series(6% 28%) were the main ones of aromatic hydrocarbons.The ratio of aromatic hydrocarbon maturity parameter vs.saturated hydrocarbon maturity parameter C 29 20S/(20S+20R) shows that some aromatic hydrocarbon maturity parameters are not suitable for low-mature oils,including MPI,MNR,DNR,etc.Meanwhile,maturity parameters for dibenzothiophene and taromatic-sterane series are more appropriate for low maturity saline lacustrine crude oils.Based on the ratio of 4,6-DMDBT/1,4-DMDBT,the R c values are within the range of 0.59% 0.72%.However,the abundance of dibenzothiophene(DBT) is low,and the dibenzofuran(DBF) content is even lower,suggesting that the crude oils were formed in a saline lacustrine anaerobic environment.The high abundance of C 26 triaromatic steroid also indicates that the source material is brackish water-saline water with strong reducibility.展开更多
GC/MS and GC/MS/MS techniques were employed to describe the characteristics of biomarker assem-blages in two sets of hydrocarbon source rocks,Jurassic and Permian,in southwestern Tarim,and the parameters for the class...GC/MS and GC/MS/MS techniques were employed to describe the characteristics of biomarker assem-blages in two sets of hydrocarbon source rocks,Jurassic and Permian,in southwestern Tarim,and the parameters for the classification of the two sets of hydrocarbon source rocks have been established. It is found that diahopane and C30-unknown terpane are abundant in Permian samples,the contents of diahopane in Jurassic samples are relatively low,and terpenoids have been detected in Jurassic samples but not in Permian source rock samples. Kekeya crude oils are abundant in diahopane and C30-unknown terpane. The results of fine oil-rock correlation indicated that Kekeya crude oils were derived mainly from the Permian hydrocarbon source rocks. However,a small amount of diterpenoid was detected in the crude oils,indicating that the Jurassic hydrocarbon source rocks also made a certain contribution to Kekeya crude oils.展开更多
Solid-liquid equilibrium of quaternary system Cd2+//Cl-, SO42-, NO3--H2O at 298 K was studied by means of an isothermal solution saturation method. Experimental results indicate that there are three univariant curves ...Solid-liquid equilibrium of quaternary system Cd2+//Cl-, SO42-, NO3--H2O at 298 K was studied by means of an isothermal solution saturation method. Experimental results indicate that there are three univariant curves BE, AE and CE, one invariant point E and three crystallization fields in the quaternary system. The quaternary system belongs to a simple type, and there are no double salts or solid solution existing. The crystallization zones of equilibrium solid phases are CdCl2·5/2H2O(AEB field), 3CdSO4·8H2O(AEC field) and Cd(NO3)2·4H2O(BEC field), respectively. The composition of the invariant point is CdCl2, Cd(NO3)2, CdSO4 and H2O and the contents of which are 17.02%, 45.50%, 4.52% and 32.96%, respectively. The physico-chemical properties of solution in the quaternary system show regular changes along with the increased cadmium concentration. The results indicate that Cd(NO3)2 possessed the highest solubility among those three salts, which means a strong transfer of Cd ion and a high pollution risk of soil environment. And the solubility of CdSO4 would be restrained as the salts existing together.展开更多
Research on the molecular fossil characteristics of heavy oil from Well Tadong-2 is of great importance to constrain the source of marine crude oils in the Tarim Basin, Xinjiang, China. The authors synthetically appli...Research on the molecular fossil characteristics of heavy oil from Well Tadong-2 is of great importance to constrain the source of marine crude oils in the Tarim Basin, Xinjiang, China. The authors synthetically applied the isotope mass spectrograph, chromatography and chromatography-mass spectrography to the studies of molecular fossil characteristics of heavy oil from Well Tadong-2 in the Tarim Basin, and the results obtained revealed that heavy oil from Well Tadong-2 is characterized by high gammacerane, high C28 sterane, low rearranged sterane and high C27-triaromatic steroid, these characteristics are similar to those of Cambrian-Lower Ordovician source rocks, demonstrating that Cambrian crude oils came from Cambrian-Lower Ordovician source rocks; condensed compounds (fluoranthene, pyrene, benzo[a]anthracene, bow, benzo fluoranthene, benzopyrene) of high abundance were detected in heavy oil from Well Tadong-2, and the carbon isotopic values of whole oil are evidently heavy, all the above characteristics revealed that hydrocarbons in the crude oils became densified in response to thermal alteration.展开更多
This paper mainly analyzed the isotopic effect of precipitation in the Yarlung Zangbo River.On the whole,the isotopic compositions of most water samples fall on the upper right of the global meteoric water line.Accord...This paper mainly analyzed the isotopic effect of precipitation in the Yarlung Zangbo River.On the whole,the isotopic compositions of most water samples fall on the upper right of the global meteoric water line.According to δD and δ18O data of the samples,the precipitation equation is figured out as δD=8 δ18O+10,showing that they are derived from precipitation but have experienced intensive evaporation.With obvious region-continental effect(a continuous depletion in heavy isotopes in water bodies occurs with increasing distance from the coast),the water presents a reducing trend of δD and δ18O westwards and southwards.Altitudinal effect is evident here,occur-ring in both trunk stream and main branches of the Yarlung Zangbo River.The distribution of water isotopic compo-sitions is concerned with the movement of precipitation clouds from the Bay of Bengal and the Nujiang River and is affected by the topographic and climatic conditions of the Tibetan Plateau.展开更多
Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic compositions, li...Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic compositions, like that of He, Ne and Ar, can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type crusts have low 84 Kr and 132 Xe abundance, while the high 3He/4He type crusts have high 84 Kr and 132 Xe abundance. The 82Kr/84 Kr ratios of the low 3He/4He type crusts are lower than that of the air, while the 83Kr/84 Kr and 86Kr/84 Kr ratios are higher than those of the air. The Kr isotopic ratios of the higher 3He/4He type crusts are quite similar to those of the air. The 128Xe/132 Xe, 130Xe/132 Xe and 131Xe/132 Xe ratios of the low 3He/4He type sample are distinctly lower than those of the air, whereas the 129Xe/132 Xe, 134Xe/132 Xe and 136Xe/132 Xe ratios are higher than those of the air. The low 3He/4He type samples have the diagnostic characteristics of the MORB, with excess 129, 131, 132, 134, 136 Xe relative to 130 Xe compared with the solar wind. The 128Xe/132 Xe, 130Xe/132 Xe and 131Xe/132 Xe ratios of the high 3He/4He type samples are slightly higher than those of the air, and the 129Xe/132 Xe, 134Xe/132 Xe and 136Xe/132 Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ratios of the low mantle reservoir are predominantly controlled by primitive He(3He) and U and Th radiogenic decayed He(4He), but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high 3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low 3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.展开更多
基金This research was funded by the State "Tenth Five-Year Plan" Key Science and Technology Program (2004BA616A02-01-01-03).
文摘According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classification of crude oils in the Tazhong area of the Tarim Basin, China. Crude oils from the area studied are classified as three genetic types: type-I is characterized by the low contents of C29 norhopane, extremely abundant contents of gammacerane, low contents of rearranged sterane and relatively high contents of regular C28 sterane; the geochemical properties of type-II crude oils are opposite to those of type-I crude oils; the parameters for type-III crude oils are intermediate between type-I and type-II. Results of oil correlation indicated that type-I crude oils were derived from Cambrian-Lower Ordovician hydrocarbon source rocks, type-II curde oils originated from Middle-Upper Ordovician hydrocarbon source rocks and type-III crude oils are of mixed origin.
基金This study was granted by the China Ministry of Science and Technology under the program of "Ecological and Environmental Monitoring, Forecasting and Management System in the Mining Area" (No. 2004DIB3J110) and "Development and Experiment of Ecological and Environmental Monitoring and Forecasting Technology for the Mining Area" (No. 2005BA901A03).
文摘Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and assessments on the environmental geochemistry and ecological risk of vanadium in the Panzhihua mining and smelting area. In the study area, anthropogenic vanadium resulted from mining, extracting and smelting of V-Ti magnetite; vanadium pollution of topsoil and sediments occurs mainly in the mining and extracting area, smelting area, slag dumping area, tailing dam and coal mining area. In the soil, the chemical speciation of vanadium shows: insoluble residue > organically bound > Fe (amorphous) oxide-bound > Mn oxide-bound > soluble component. Vanadium pollution can cause potential harmful effects on ecological systems, and lead to animal poisoning and human disease. So vanadiam pollution should be monitored on a regular basis in the Panzhihua area.
文摘The geochemical characteristics of crude oils and reservoir core extracts from the Kuche petroleum system are described and studied systematically by means of various geochemical techniques and methods to acquire molecular information. The results suggest crude oils from the petroleum system can be divided into two groups: marine oils and non-marine oils. The former represents the dominant oils found in the area. Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs, with Lower Tertiary sandstone reservoirs in the Yaha oilfield of the Tarim Basin. However, based on the ratio of 20S/(20S+20R)C-29 sterane as a maturity parameter, lacustrine oils filled into the Tertiary reservoirs in the direction toward the western part of the petroleum system. In contrast, according to the fact that methylcyclohexane indices of eastern oils are greater than those of western oils, the location in which coal-generated oils filled into the Tertiary reservoirs lies in the eastern part of the petroleum system.
文摘Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin, Xinjiang, China, showed that even though there are quite a number of factors affecting the distributional and compositional characteristics of neutral nitrogen-containing compounds in crude oils, the distributional and compositional characteristics of crude oils whose source conditions are approximate to one another are influenced mainly by the migration and fractionation effects in the process of formation of oil reservoirs. In addition, crude oils in the Tazhong region show obvious migration-fractionation effects in the vertical direction. Carboniferous crude oils are characterized by high migration parameters and low compound concentrations, just in contrast to Ordovician crude oils. This indicates that crude oils from shallow-level oil reservoirs were derived from those of deep-level oil reservoirs via faults, unconformable contact or carrier beds. Crude oils from the Tazhong region show some migration-fractionation effects in the lateral direction, but mixing of crude oils derived from different hydrocarbon source rocks in the process of formation of oil reservoirs made it more complicated the migration and accumulation of crude oils, as well as the formation of oil reservoirs.
文摘The plane tree, which is a valuable tool to detect atmospheric pollution, is one of the most common trees in European cities. Soil and leaf samplings were carried out in Barcelona and its environs (NE Spain) to establish the soil-plant relationship. Dry and ashed leaves and soils were analyzed by Instrumental Neutron Activation Analysis and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP/OES) at the ACTLABS laboratories in Ontario, Canada. Given that diesel is the main fuel used in vehicles in Europe, we sought to establish the role of diesel in atmospheric pollution. Diesel samples were obtained from service stations and analyzed after preconcentration using ICP/MS at the geochemistry laboratories of the University of Barcelona. The average content of diesel oil shows high values of Pb, Cu, Cr, Ag, Cd and Mn. High values of Pb, Cu, Au, Hg and Sb in leaves and soils were detected downtown and along main roads outside the city, whereas low levels of these elements were observed in rural areas.
基金Supported by the National Natural Science Foundation of China (No. 40973041)
文摘Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show that the crude oils have even-odd carbon predominance for n-alkanes.In shallow reservoir,part of crude oils suffered biogenic degradation.As for normal oils,they have low Pr/Ph ratios with abundant gammacerane and C35 homohopane,which indicate that the crude oils are formed in strong reducing salt water environment.Compared deep(E13) reservoir with shallow(N1-N12) reservoir,the ancient salinity of sedimentary environment of N1--N12 crude oils is slightly higher than that of E13 crude oils;the C-21/C+22 ratios of crude oils are 1.02-1.71 with a higher abundance of C27 sterane,which shows that their mainly origin matrix are bacteria and algae;the C29 sterane 20S/(20S+20R)is generally low,the ratio in deep E13 reservoir distributes between 0.31 and 0.40,but in shallow reservoir is relatively low with 0.29-0.36.At the same time,C29 sterane αββ/(αββ+ααα)and Ts/Tm both are extremely lower.All the above show that the crude oils in Gas Hure are mainly low mature oils,although the maturity of deep reservoir crude oils is slightly higher than shallow one.
基金funded by the National Natural Science Foundation of China (Grant No. 40973041)
文摘Based on the systematic study of aromatic hydrocarbons in over 100 crude oil samples collected from the Tabei and Tazhong uplifts in the Tarim Basin,the western depression area in the Qaidam Basin and the Tabei depression in the Turpan Basin,the geochemical characteristics of the marine(Tarim Basin),saline lacustrine(Qaidam Basin),and swamp(Turpan Basin) oils were investigated.The marine oils from the Tarim basin are characterized by relatively low abundance of diaromatic hydrocarbons such as biphenyl and naphthalene,and relatively high abundance of triaromatic hydrocarbons including phenanthrene,dibenzothiophene and fluorene.In contrast,the swamp oils from the Turpan Basin are dominated by the highest relative abundance of diaromatic hydrocarbons and the lowest relative abundance of triaromatic hydrocarbons in all the oil samples in this study.The relative abundance of diaromatic and triaromatic hydrocarbons in the saline lacustrine oils from Qaidam Basin is between that in Tarim oils and Turpan oils.Aromatic parameters based on the isomer distributions of dimethylnaphthalenes(DMN),trimethylnaphthalenes(TMN),tetramethylnaphthalenes(TeMN) and methylphenanthrenes(MP),i.e.,1,2,5-trimethylnaphthalene(TMN)/1,3,6-TMN ratio,1,2,7-TMN/1,3,7TMN ratio,(2,6-+2,7-)-dimethylnaphthalenes(DMN)/1,6-DMN ratio,1,3,7-TMN/(1,2,5-+1,3,7-)TMN,1,3,6,7-TeMN/(1,3,6,7-+1,2,5,6-+1,2,3,5-)-TeMN ratio and MP index,may reflect the diversity of organic source input,thermal maturity and depositional environments.In addition,the dibenzothiophenes(DBTs)/fluorenes(Fs) and dibenzofurans(DBFs)/Fs ratios were found to the very useful and effective in determining genetic types of crude oils for the marine,saline lacustrine,and swamp depositional environments,and for oil-oil correlations.
基金supported by the geological survey project of China Geological Survey (No.20021400013)the Science Development Fund of Yangtze University
文摘This paper dealt with the Pb contents and Pb isotopic composition of the West Lake Longjing tea. The results showed that in the tea leaves, from young leaf →old leaf →tea limb, the Pb contents tend to increase gradu-ally from 1.63 →4.84 →6.07×10-6, wich revealed that the Pb was accumulated gradually in the tea. After cleaned, the Pb contents of tea leaves were significantly reduced. This indicated that the deposits on the surface of tea leaves made a great contributuion to Pb contents. The survey results for soils in the relevant tea gardens showed that soil from the Longjing tea garden has higher Pb contents, with an average level of 49.6×10-6, two times those of common soils (24×10-6) in China. Results of the systematic analysis for tea, tea garden soil and the samples with the relevant background of the Pb isotopic composition displayed that the Pb isotopic ratio of tea is 206Pb/207Pb=1.164±0.005 (2σ). The ratio of 206Pb/207Pb for the soil gradually decreased from residue phase, soil dilute acid extract phase, and then to urban topsoil, i.e., 1.175 →1.171 →1.170. The 208Pb/(206Pb+207Pb) ratios also show a similar variation trend. 206Pb/207Pb ratios in the samples with the relevant background were: vehicle exhaust, 1.124; coal-combustion, 1.156; atmosphere, 1.168; and water, 1.166. Comparative studies have shown that Pb pollution is popular in the environ-mental media (soil, atmosphere, water) in Hangzhou. With the aggravation of Pb pollution, the Pb isotopic composi-tion gradually changed from the natural background (soil residues) to the direction of automobile exhaust. This phe-nomenon could illustrate that the pollution source was the vehicle exhaust, while the coal-combustion contributed little to environmental pollution in Hangzhou. The Pb of the Longjing tea came mostly from soluble phase Pb in the polluted soil. Moreover, secondary pollution was caused by vehicle exhaust.
基金supported financially by the National Natural Scientific Foundation of China (Grants No. 40872069 and 41173059)the National Basic Research Program of China (973 Program) (Grants No. 2015CB453000)+1 种基金China Geological Survey (Grants No. 12120113095500)the Foundation of China Nuclear Geology (Grants No. 201148)
文摘Whole rock major and trace element geochemistry together with zircon U-Pb ages and Sr-Nd isotope compositions for the Middle Eocene intrusive rocks in the Haji Abad region are presented. The granitoid hosts, including granodiorite and diorite, yielded zircon U-Pb ages with a weighted mean value of 40.0 ± 0.7 Ma for the granodiorite phase. Mafic microgranular enclaves(MMEs) are common in these plutons, and have relatively low SiO_2 contents(53.04-57.08 wt.%) and high Mg#(42.6-60.1), probably reflecting a mantle-derived origin. The host rocks are metaluminous(A/CNK = 0.69-1.03), arc-related calc-alkaline, and I-type in composition, possessing higher SiO_2 contents(59.7-66.77 wt.%) and lower Mg#(38.6-52.2); they are considered a product of partial melting of the mafic lower crust. Chondritenormalized REE patterns of the MMEs and granitoid hosts are characterized by LREE enrichment and show slight negative Eu anomalies(Eu/Eu* = 0.60-0.93). The host granodiorite samples yield(^(87)Sr/^(86)Sr);ratios ranging from 0.70498 to 0.70591,positive eNd(t) values varying from +0.21 to +2.3, and TDM2 ranging from 760 to 909 Ma, which is consistent with that of associated mafic microgranular enclaves(^(87)Sr/^(86)Sr)i = 0.705111-0.705113, ε_(Nd)(t)= +2.14 to +2.16, T_(DM2) = 697-785 Ma). Petrographic and geochemical characterization together with bulk rock Nd-Sr isotopic data suggest that host rocks and associated enclaves originated by interaction between basaltic lower crust-derived felsic and mantlederived mafic magmas in an active continental margin arc environment.
文摘In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan pro- file, which is located in Chaoxian County, south of Anhui Province, are described in the light of gas chromatogra- phy/mass spectrometric (GCMS) analysis on the qualitative and quantitative basis. Based on the investigation of the biomarker assemblage characteristics of possible source rocks developed in the area studied, a conclusion is drawn that the oilshow was generated from the Nanlinghu Formation source rocks (abbreviated as T1n), instead of the Qixia Formation source rocks (abbreviated as P1q). It is pointed out that the T1n is of strong potential for future oil explora- tion, and therefore much attention should be paid to it.
文摘Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used successfully in such cases that conventional production logging techniques are powerless. Taking low-concentration anthracene as internal standard, we calculated the absolute concentrations!of fingerprints, initially made some experiments directly on biodegradation of crude oils, and calculated production allocation in the Gudong Oil field. Compared with the production logging, this method has made up for the deficiencies of the former GC fingerprint technique. It will find wide applications in monitoring the trend of production in various oil-fields.
文摘Terrestrial faulted lacustrine basin is considered as a favorable place for the development of source rocks,especially the fault basins in eastern China.Based on molecular composition study of saturated and aromatic hydrocarbons in the extracts of source rocks of the Yingcheng and Shahezi formations in the Lishu Fault Depression,it is revealed that the extracts of source rocks are provided with low ratio of Pr/Ph,low content of C24 tetracyclic terpanes,high content of tricyclic terpanes and gammacerane,relatively high content of C27 steranes in the sag belt and its periphery;relatively high ratio of Pr/Ph,relatively high content of tetracyclic terpanes and gammacerane,low content of C27 steranes and obvious advantages of C29 steranes in its gentle slope belt;with high ratio of Pr/Ph,high content of C19,C20 tricyclic and C24 tetracyclic terpanes,very low content of gammacerane and C27 steranes,and high content of C29 steranes in the edge of fault depression.According to the organic matter input and sedimentary environment,three types of source rocks have been established,which,respectively,are the mode of mixing organic matter input in deep and semi-deep lake,the advantage of terrigenous input in shallow lake and terrigenous input in shore-shallow lacustrine.The first mode is supposed to generate oil and gas,while the second one tends to generate oil.The distribution characteristics of oil and gas in the Lishu Fault Depression are very likely to be controlled by hydrocarbon generating characteristic of different source rock types.
文摘Light hydrocarbons, especially C-7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K-1 values [(2-MH+2,3-DMP)/(3-MH+2,4-DMP)] of crude oils vary from a lowest value of {0.78}, to a highest value of {1.54}, but the K-1 values of the majority of oil samples (80%) range from {0.90} to {1.20}. However, the absolute contents of (2-methylhexane+ 2,3-dimethylpentane) and (3-methylhexane+2,4-dimethylpentane) in the total light hydrocarbons (C-4-C-7) show a similar variation trend. The variation of K-1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C-7 light hydrocarbons in light of the steady-state catalytic hypothesis, non-marine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.
基金supported jointly by the National Natural Science Foundation of China (Grant No. 40973041)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20104220110001)
文摘Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydrocarbons in oils were studied systematically in this paper.Among those constitutes,naphthalene(43% 59%),phenanthrene(12% 21%) and taromatic-sterane series(6% 28%) were the main ones of aromatic hydrocarbons.The ratio of aromatic hydrocarbon maturity parameter vs.saturated hydrocarbon maturity parameter C 29 20S/(20S+20R) shows that some aromatic hydrocarbon maturity parameters are not suitable for low-mature oils,including MPI,MNR,DNR,etc.Meanwhile,maturity parameters for dibenzothiophene and taromatic-sterane series are more appropriate for low maturity saline lacustrine crude oils.Based on the ratio of 4,6-DMDBT/1,4-DMDBT,the R c values are within the range of 0.59% 0.72%.However,the abundance of dibenzothiophene(DBT) is low,and the dibenzofuran(DBF) content is even lower,suggesting that the crude oils were formed in a saline lacustrine anaerobic environment.The high abundance of C 26 triaromatic steroid also indicates that the source material is brackish water-saline water with strong reducibility.
基金financially supported by the National Natural Science Foundation of China (Grant No.40773039)
文摘GC/MS and GC/MS/MS techniques were employed to describe the characteristics of biomarker assem-blages in two sets of hydrocarbon source rocks,Jurassic and Permian,in southwestern Tarim,and the parameters for the classification of the two sets of hydrocarbon source rocks have been established. It is found that diahopane and C30-unknown terpane are abundant in Permian samples,the contents of diahopane in Jurassic samples are relatively low,and terpenoids have been detected in Jurassic samples but not in Permian source rock samples. Kekeya crude oils are abundant in diahopane and C30-unknown terpane. The results of fine oil-rock correlation indicated that Kekeya crude oils were derived mainly from the Permian hydrocarbon source rocks. However,a small amount of diterpenoid was detected in the crude oils,indicating that the Jurassic hydrocarbon source rocks also made a certain contribution to Kekeya crude oils.
基金Supported by the National Natural Science Foundation of China(No.40803031)
文摘Solid-liquid equilibrium of quaternary system Cd2+//Cl-, SO42-, NO3--H2O at 298 K was studied by means of an isothermal solution saturation method. Experimental results indicate that there are three univariant curves BE, AE and CE, one invariant point E and three crystallization fields in the quaternary system. The quaternary system belongs to a simple type, and there are no double salts or solid solution existing. The crystallization zones of equilibrium solid phases are CdCl2·5/2H2O(AEB field), 3CdSO4·8H2O(AEC field) and Cd(NO3)2·4H2O(BEC field), respectively. The composition of the invariant point is CdCl2, Cd(NO3)2, CdSO4 and H2O and the contents of which are 17.02%, 45.50%, 4.52% and 32.96%, respectively. The physico-chemical properties of solution in the quaternary system show regular changes along with the increased cadmium concentration. The results indicate that Cd(NO3)2 possessed the highest solubility among those three salts, which means a strong transfer of Cd ion and a high pollution risk of soil environment. And the solubility of CdSO4 would be restrained as the salts existing together.
基金funded by the National Natural Science Foundation of China (Grant No. 40773039)
文摘Research on the molecular fossil characteristics of heavy oil from Well Tadong-2 is of great importance to constrain the source of marine crude oils in the Tarim Basin, Xinjiang, China. The authors synthetically applied the isotope mass spectrograph, chromatography and chromatography-mass spectrography to the studies of molecular fossil characteristics of heavy oil from Well Tadong-2 in the Tarim Basin, and the results obtained revealed that heavy oil from Well Tadong-2 is characterized by high gammacerane, high C28 sterane, low rearranged sterane and high C27-triaromatic steroid, these characteristics are similar to those of Cambrian-Lower Ordovician source rocks, demonstrating that Cambrian crude oils came from Cambrian-Lower Ordovician source rocks; condensed compounds (fluoranthene, pyrene, benzo[a]anthracene, bow, benzo fluoranthene, benzopyrene) of high abundance were detected in heavy oil from Well Tadong-2, and the carbon isotopic values of whole oil are evidently heavy, all the above characteristics revealed that hydrocarbons in the crude oils became densified in response to thermal alteration.
文摘This paper mainly analyzed the isotopic effect of precipitation in the Yarlung Zangbo River.On the whole,the isotopic compositions of most water samples fall on the upper right of the global meteoric water line.According to δD and δ18O data of the samples,the precipitation equation is figured out as δD=8 δ18O+10,showing that they are derived from precipitation but have experienced intensive evaporation.With obvious region-continental effect(a continuous depletion in heavy isotopes in water bodies occurs with increasing distance from the coast),the water presents a reducing trend of δD and δ18O westwards and southwards.Altitudinal effect is evident here,occur-ring in both trunk stream and main branches of the Yarlung Zangbo River.The distribution of water isotopic compo-sitions is concerned with the movement of precipitation clouds from the Bay of Bengal and the Nujiang River and is affected by the topographic and climatic conditions of the Tibetan Plateau.
基金The National Natural Science Foundation of China under contract No.40706028
文摘Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic compositions, like that of He, Ne and Ar, can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type crusts have low 84 Kr and 132 Xe abundance, while the high 3He/4He type crusts have high 84 Kr and 132 Xe abundance. The 82Kr/84 Kr ratios of the low 3He/4He type crusts are lower than that of the air, while the 83Kr/84 Kr and 86Kr/84 Kr ratios are higher than those of the air. The Kr isotopic ratios of the higher 3He/4He type crusts are quite similar to those of the air. The 128Xe/132 Xe, 130Xe/132 Xe and 131Xe/132 Xe ratios of the low 3He/4He type sample are distinctly lower than those of the air, whereas the 129Xe/132 Xe, 134Xe/132 Xe and 136Xe/132 Xe ratios are higher than those of the air. The low 3He/4He type samples have the diagnostic characteristics of the MORB, with excess 129, 131, 132, 134, 136 Xe relative to 130 Xe compared with the solar wind. The 128Xe/132 Xe, 130Xe/132 Xe and 131Xe/132 Xe ratios of the high 3He/4He type samples are slightly higher than those of the air, and the 129Xe/132 Xe, 134Xe/132 Xe and 136Xe/132 Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ratios of the low mantle reservoir are predominantly controlled by primitive He(3He) and U and Th radiogenic decayed He(4He), but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high 3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low 3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.
