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    Deep Geodynamics of Yanshain Movement
    WU Fu-yuan, SUN De-you, ZHANG Guang-liang, REN Xiang-wen
    J4   
    Abstract1965)      PDF (2278KB)(1942)       Save
    The eastern China was characterized by intensive magmatic ac tivities, structrual deformation, basin formation and mineralization in the Mesozoic, whic h wa s described as the Yanshain Movement Wong (1927). Although a lot of studies have been conducted in the past 70 years on the Yanshain Movem ent, a warmly debate still exists about its geodynamic background, such as the sub duction and back-arc extension of Pacific plate, continental -continental collisi on, sheared strike-slip continental margin, impacting and lithosph eric thinning , etc. A comprehensive study about the mineralogical, petrological and Sr-Nd isotopic features of Cenozoic basalts and their mantle xenoliths has indicated t hat the eastern China in Yanshain Period was characterized by lithospheric delaminat ion, especially the direct contact of asthenospheric mantle with the crust. Most of the pre-existed ancient lithospheric mantle had been delaminat ed, the present lithospheric mantle was formed since the Late Mesozoic. According to the presen t st udy, this lithospheric removal is probably related to the subduction of Pacific Oceanic Plate. The early stage (170 Ma or so) of subduction of eastern oceanic p lat e thickened the lithosphere in the eastern China, which resulted in the mantle d elamination in 160 and 145~120 Ma duo to the gravity instability of thicken ed lithosphere. Therefore, the nature of Yanshain movement is the thinning, even disappearing of lithospheric mantle beneath eastern China. This phenomenon is r are in the world and was reported only in the Basin and Range of western United States. Du ring the period of lithospheric removal, the asthenosphere upwelling and heating , and the underplating of mantle-derived magma in the lower cr ust resulted in th e intensive Late Mesozoic magmatism-tectonism-minera lization of Yanshain Movement in China. This research also suggests that the present lithospheric mantle beneath e astern China is juvenile, and does not correspond to the old ages found in the o verlyi ng crustal rocks. This implies a mantle-crust decoupling, which is inconsistent with the results of present researches on the major Archean Cratons in the world. Th erefore, further investigation should be conducted to study the mechanism of th is process.
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    Cited: Baidu(338)
    My Thinking about Granite Geneses of South China
    ZHOU Xin-min
    J4   
    Abstract1662)      PDF (2896KB)(2441)       Save
    The characteristics,genetic models and tectonic frameworks of the granites for four geological periods in South China are described and discussed in this paper.Several geological problems of South China which are worth further thinking over are raised by the present author
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    Cited: Baidu(312)
    Major Transformation of Subcontinental Lithosphere beneath North China in Cenozoic-Mesozoic: Revisited
    ZHOU Xin-hua
    J4   
    Abstract1831)      PDF (946KB)(2173)       Save
    The dramatic change of subcontinental lithosphere mantle (SCLM) beneath North China in Cenozoic-Mesozoic has been a hotly debatable issue in Earth science community. This paper presents an overview on topics related to this field, such as temporal and spatial characteristics of lithospheric transformation, progresses in geophysical and geological studies, latest applications of new analytical technology, mechanism and deep processes involved, as well as the dynamic regime in tectonics.The author emphasizes to adopt the term of transformation, instead of the term of thinning as used so far, to describe this large scale geodynamic event in East Asia. It is also noted that "the destruction of craton" is not a proper phrase for delineating such an event in North China. Meanwhile, a global link between Mesozoic mantle overturn and transformation of SCLM in eastern China has been proposed and stressed, which opens a variety of research approaches to further studies.
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    Cited: Baidu(159)
    Is the Jiangnan Orogenic Belt a Grenvillian Orogenic Belt:Some Problems about the Precambrian Geology of South China
    Zhou Jin-cheng
    J4   
    Abstract1262)      PDF (542KB)(2234)       Save
    This discussion is made on the basis of age data reported in recent years of 21 century, which have been obtained by SHRIMP, LA-ICP-MS zircon U-Pb and other new dating methods. The assembly of the Yangtze and Cathysia blocks took place between 860 and 820 Ma. The continent-continent collision event forming Grenvillian orogenic belt spanned a period from 1 190 to 980 Ma. Therefore, the collision between the Yangtze and Cathysia blocks occurred about 320~160 Ma later. The basement strata in the Jiangnan orogenic belt underwent thoroughly greenschist facies metamorphism. High grade metamorphism, such as granular facies existed widely in the Grenvillian orogenic belt, has never been found in the metamorphic sedimentary-igneous rocks in the Jiangnan orogenic belt. Because of above two reasons, the Jiangnan orogenic belt should not be considered as a Grenvillian orogenic belt. It is proposed that the Jiangnan orogenic belt might be a product of collision between two neighborhood blocks during the transformation from the Rodinia to Gondwana supercontinent. The Sibao, Lengjiaxi and Fanjingshan groups in the western part of the Jiangnan orogenic belt, as basement strata, were previously believed to be Mesoproterozoic. Recent dating results of detrital zircons from the sandstones of the basement strata indicate that these strata have the maximum depositional ages of 870~860 Ma, i.e. Neoproterozoic. The S-type granites distributed along the Jiangnan orogenic belt may be considered as a petrological record of the continent-continent collisional event between the Yangtze and Cathaysia blocks rather than the products of plume magmatism. Some Neoproterozoic mafic volcanic-intrusive rocks (~760 Ma) from the western part of Jiangnan orogenic belt and the mafic rocks from the bimodal volcanic rocks (803~818 Ma) distributed around or within the Yangtze block or within Cathaysia block show some geochemical signatures of OIB. However, their exposed volumes are very small. They might have been generated in the post-orogenic extensional stage due to local upwelling of asthenospheric mantle. It is believed that they shouldn't be considered as petrological evidence of breakup of the Rodinia.
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    Cited: Baidu(125)
    Post-Orogenic Granites with an Age of 1800Ma in Luliang Area, North China Craton: Constraints from Isotopic Geochronology and Geochemistry
    GENG Yuan-sheng1, YANG Chong-hui1, SONG Biao1 2, WAN Yu-sheng1 2
    J4   
    Abstract1817)      PDF (2936KB)(1025)       Save
    Major trace element characteristics and zircon U-Pb SHRIMP dating of the Luyashan augite-monzonites and Yunzhongshan granites in Luliang area, Shanxi Province indicate that the Luyashan augitemonzonites and Yunzhongshan granites belong to the post-orogenic granite.Zircon grains from the Luyashan augite-diorite yield a SHRIMP U-Pb age of 1 794±13 Ma and zircon grains from the Yunzhong-shan granite a SHRIMP age of 1 801±llMa. Determination of post-orogenic granites at ca.1 800 Ma provides direct evidence for constraints on the ending time of the orogeny at the end of Paleoproterozoie.
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    Cited: Baidu(122)
    SEM Study on Jarosite Mediated by Thiobacillus ferrooxidans
    ZHU Chang-jian, LU Jian-jun, LU Xian-cai, WANG Ru-cheng, LI Qi
    J4   
    Abstract1221)      PDF (1986KB)(1121)       Save
    Jarosite is a major secondary mineral formed in acid supergene environment by oxidation of metal sulphide.Thiobacillus ferrooxidans occurring extensively in metal sulphide ore district has an important effect on oxidation of metal sulphide and formation of secondary minerals.In order to discuss the effect of Thiobacillus ferrooxidans on the formation of jarosite,two parallel experiments were conducted for preparation of jarosite:chemical experiment and biologically mediated experiment.The compositions and morphological features of these two groups of jarosites have been investigated by means of XRD,SEM and EDS.The study indicates that full propagation of Thiobacillus ferrooxidans in the solution is beneficial to the formation of jarosite.The oxidation rate of Fe2+in the solution is probably the main factor that affects crystallization of jarosite.Thiobacillus ferrooxidarts induces a rapid crystallization of jarosite by increasing the supply rate of Fe2+ on the mineral surface.Jarosite mediated by Thiobacillus ferrooxidans has a better crystalline form than that synthesized by chemical method.
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    Cited: Baidu(105)
    Tectonic Setting of the Northern Margin of South China Sea
    WU Shi-min, ZHOU Di, QIU Xue-lin
    J4   
    Abstract2079)      PDF (2195KB)(1172)       Save
    There are different deformation characteristics between the east and west part of the number 1 fault in the northern margin of South China Sea(SCS). The east part includes the Beibuwan basin, Qiongdongnan basin, Zhujiangkou basin and Taixi basin, with NE-EW strike segment of normal faults and traverse fold. The west part includes Yinggehai basin, with NW strike transtensiona1 faults. Based on with the features of magmatics, subsidence, sedimentary fill, crust structure in the northern margin of SCS, the authors believe that the east part margin exist three relative tectonic active periods, i.e. 40—50, 28—30, 10—5Ma. They exhibited different dynamics characteristic respectively.The former two episodes are related to the break up processing of SCS. The third is nothing to do with it. The magmatics at the northern margin of SCS are not the correspond activity with the rifting of SCS. Therefore, the east part of the northern margin of SCS belongs to the non-volcanic passive margin according to its forming mechanism. The active factors are overlapped by the interaction of surrounding plates. The west part may be related to the collision of India-Tibet and it is not a part of the northern margin based on the formation mechanism.
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    Cited: Baidu(88)
    New Thought about the Tectonic Evolution of the South China: with Discussion on Several Problems of the Cathaysian Old Land
    MA Ri-shi
    J4   
    Abstract1326)      PDF (305KB)(1909)       Save
    During Neoproterozoic to Early Paleozoic, the South China was a marginal basin captured by the Yangtze active continental margin, filled with huge thick flysch, sandstone, and shale sediments. At the end of the Early Paleozoic, the Fujian coast arc collided with the Wuyi arc and then both of them collided with the active continental margin of the Yangtze Block, which was so-called an orogeny of the South China. These resulted in the metamorphism of the marginal basin sediments of the South China and intense tectonic deformation, then formed a series of nappe structures and granite magmatism. Accordingly, the South China was an Early Paleozoic orogenic belt instead of the Cathaysian Block (Paleocontinent). However, as there still have some scholars continue to use this old term(the Cathaysian Block), it brings on the argument that the South China is an orogenic belt or the Cathaysian Block. Professional term reflects scholars’ academic ideology and research direction, therefore it is necessary to discuss the tectonic property of the South China. This paper discusses some problems of the Cathaysian Block and briefly points of the nomenclature about geologic structural units.
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    Cited: Baidu(73)
    A Discussion on the Adsorption Mechanism of Palygorskite Clay to Pollutants in Wastewater
    CHEN Tian-hu
    J4   
    Abstract1521)      PDF (1467KB)(1426)       Save
    Palygorskite is a chain-layered silicate, with a a perture pass of 3.8 ×6.3A.It is gene?rally regarded that because this mineral has microapertur e pass and relatively larger specific surface area, the palygorskite clay is capable o f adsorbing the pollutants in wastewater. Based on the crystal structure of paly gorskite,its adsorption selectivity and our adsorption experiments, the present author holds the following opinion: because most molecules and hydrated ions hav e the diameters larger than that for the aperture pass of palygorskite, they u sually can not get into the aperture pass of palygorskite. Moreover, the inner ape rture pass of palygorskite preferentially adsorbs the water molecules. Terefore, in most cases during wastewater disposal processing the adsorption of palygorsk ite to pollutants is not an inner-surface adsorption, but an outer-surface ad sorption. This outer-surface adsorption is a kind of colloidal and ion exchange ad s orption. Besides the acidity of the solutions, the interaction of coexisting col loidal montmorillonite and palygorskite may play an important role in adsorption ability of palygorskite clay.
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    Cited: Baidu(73)
    Cenozoic Geotectonic Evolution of the Bohai Basin
    TANG Liang-jie
    J4   
    Abstract1930)      PDF (2177KB)(1828)       Save
    Choosing one well separately in eight main sags of the Bohai basin and analysing the subsidence history of each well,we come to a conclusion that the subsidence characteristics of different sags were different. The southern part and the northern part of the basin subsided first, and the central part subsided at a later time. The subsidence center migrated from outside towards the basin center, which reflects the difference of tectonics in different parts of the basin. We made a balanced section analysis for the Liaodong Bay. Combining the subsidence history, we divided its Cenozoic tectonic history into three stages: (a) Rift stage.The time from the Kongdian Formation to the fourth member of the Shahejie Formation is the early rift stage, and the time of the third member of Shahejie Formation is the intensive rift stage; (b) Fault depression stage. The time from the second member of the Shahejie Formation to the first member of the Shahejie Formation is the early fault depression stage, and the period from the third member of the Dongying Formation to the second member of the Dongying Formation is the intensive fault depression stage; (c) Depression stage. This stage lasted from the first member of the Dongying Formation to the Quaternary.
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    Cited: Baidu(66)
    Structural Elements Association of Yanshan Orogenic Belt,North China
    DENG din-fu, SU Shang-guo, ZHAO Guo-chun, LIU Cui
    J4   
    Abstract1408)      PDF (2325KB)(959)       Save
    Using the concept of structural elements association of orogenic belt.we studied the evolution of Yanshan orogenic belt.The structural elements association characteristics of each stage of Yanshan orogenic belt are as follows:During the pre-and initial orogenic episode(J1),in the earlier stage of Early Jurassic,it is preorogenic extension.The structural elements associations are:triple junction rift, intraplate basalt,coal-bearing sedimentary formation;In the later stage of Early Jurassic.it is incipient orogenic compression.The structural elements associations are: northward verging fold and thrust, Jiulongshan molasse-like formation,chloritoid-staurolite-kyanite low temperature, middle-high pressure metamorphic belt.During the early orogenic episode(J2),in earlier stage of Middle Jurassic.it is syn-orogenic extension. Structural elements associations are: volcanic basins and intrusive rocks with lithosphere uplift and extension,linear distribution of volcanic rocks;In the later stage of Middle Jurassic, it is compression regime.Structural elements associations are:thrusting and folding,molasse formation.syn-tectonic intrusive rocks and am phibole facies metamorphiesm;During the peak orogenic episode(J3),in the earlier stage of Late Jurassic,it is syn-orogenic extension. Structural elements associations are:volcanic basins and intrusive rocks with lithosphere uplift and extension, planar distribution of vo1canic rocks,high-pressure trachyte,voluminous rhyolite;in the later stage of late Jurassic,it is compression structure, Structural elements associations are:thrusting and folding, molasse formation, syn-tectonic intrusive rocks and amphibole facies metamorphism,high-pressure syenite;During the earlier stage of Early Cretaceous,it is late-orogenic episode.Structural elements associations are:local compression structure,lake facies sedimentary formation,peralkaline quartz syenite,miarolitic granite,komatiitic gabbro;During the later stage of Early Cretaceous,it is post-orogenic extension episode. Structural elements associations are:normal faulting,metamorphic core complex,bimodal dikes,typical peralkaline granite and coal-bearing sedimentary formation.
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    Cited: Baidu(56)
    Weathering of Silicate Minerals by Microorganisms in Culture Experiments
    LIAN Bin1 3, CHEN Jun1, FU Ping-qiu2, LIU Gong-qiang2, CHEN Ye3
    J4   
    Abstract1621)      PDF (2306KB)(786)       Save
    Interactions between microorganisms and minerals take place widely on the Earth,which lead to dissolution or precipitation of minerals and thus play an important role in the natural environment and economic development.The study of mineral weathering by microorganisms involves many fields and disciplines. Furthermore,weathering of minerals is related to the formation and evolution of soil,development of vegetation and formation of mineral deposits.This paper focuses on mineral weathering by silicate bacteria.Potassium feldspar,illite and other common minerals were selected for this study.These minerals were incubated in nitrogen—free medium containing bacteria.During incubation samples were collected from the culture and analyzed using X—ray diffraction and electron microscope.The results showed that the bacteria indeed eroded the surface of the testing minerals,which were characteristic of round shapes and uneven surface.The mineral particles were covered with numerous bacteria.Furthermore.bacteria selectively degraded different minerals due to difference in mineral crystal structure.In the absence of bacteria,minerals remained intact,which were characterized by sharp edges and corners.The mechanisms of mineral weathering by silicate bacteria were also discussed.
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    Cited: Baidu(53)
    Investigation on the Salt Lake Source Rocks for Middle Shasi Column of Dongying Depression
    ZHU Guang-you1, JIN Qiang2, DAI Jin-xing1, ZHANG Shui-chang1, ZHANG Lin-ye3, LI Jian1
    J4   
    Abstract2467)      PDF (2659KB)(919)       Save
    Evaporite is well developed in the middle Shasi column of Shahejie Formation,Tertiary system in Dongying Depression,where the thickness of saliferous layers with mudstone exceeds 1000 m in the southern Shengtuo and central rift zone.Analysis of many samples and study on sedimentary system show that the lake basin was in an under-filling condition.A deep water evapofite formation model was established.The geochemical characteristics of dark gray mudstone and shale in evapofite layers record the sedimentary environment of salt lake.The high salt medium is beneficial to organic concentration and preservation.The gray mudstone and shale in middle Shasi column was a kind of high quality source rocks in Dongying Depression.
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    Cited: Baidu(51)
    A Study on Land Subsidence in Shanghai
    LI Qin-fen,WANG Han-mei.
    J4   
    Abstract1348)      PDF (3808KB)(1017)       Save
    This paper introduces some new viewpoints getting from the studying on land subsidence of Shanghai in recent years. It also presents some primary achievements obtained in the processes of research on the early forecasting warning system of land subsidence in Shanghai. With consideration of the 11th Five-Year-Plan of land subsidence prevention and cure in Shanghai, this paper points out the existing problems of current studying work which need to be solved urgently, and gives some suggestion on the future study and research direction.
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    Cited: Baidu(51)
    Analysis of Northern Jiangsu Prototype Basin from Late Cretaceous to Neogene
    SHU Liang-shu, WANG Bo, WANG Liang-shu, HE Guang-yu
    J4   
    Abstract1898)      PDF (3084KB)(1260)       Save
    The Northern Jiangsu basin is an oil-gas bearing half graben-like basin of Middle Caenozoic era in Eastern China, and is mainly made up of three structural units: the Dongtai sag, the Yancheng - Funing sag and the Jianhu upheaval. The heaves in sags and depressions in upheavals are the minor units of the basin. Based on the prototype analysis method, this paper deals with erosion source area, subsidence history, evolution of sedimentation center, borderline structure and sedimentation intervals of the northern Jiangsu basin, and also estimates its subsidence quantity and denudation quantity. The paper suggests that basin's formation and evolution process can be divided into four stages: compressed foreland basin, back arc tensile rift basin, massive tensile fault basin and heatsinking sag basin. Its rich sediments came from following five erosion source areas: the Binhai upheaval on the northeast of the basin, the Shandong- Jiangsu upheaval on the northwest of the basin, the Dabie mountain on the west of the basin, the Zhangbaling mountains on the southwest of the basin, and the Paleozoic sedimentary area of Yangzhou - Nanjing and Zhenjiang on the south of the basin ; There were four uplifting and denudation events ( the Yizheng event, the Wubao event, the Zhenwu event and the Sanduo event) during the basin evolution, which played a very important role for the formation of the asymmetric dustpan-shaped basin. The resumed subsidence history of the basin commendably reflects the evolution history of the basin from Late Cretaceous to Neogene.
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    Cited: Baidu(49)
    The Metalliferous Mineralization Associatied with Adakitic Rocks
    WANG Qiang, TANG Gong-jian, JIA Xiao-hui, ZI Feng, JIANG Zi-qi, XU Ji-feng, ZHAO Zhen-hua
    J4   
    Abstract1808)      PDF (1260KB)(4981)       Save
    Adakitic rocks have important implications for the metalliferous mineralization. This paper introduces the nomenclature of“ adakitic rocks”, the distribution and tectonic settings of the adakitic rocks associated with metalliferous mineralization. The factors that the adakitic rocks are favorable for the metalliferous mineralization are discussed in detail at last. Similar to a subducted oceanic crust-derived adakite, the“adakitic rocks”are characterized by the following geochemical characteristics: SiO2≥56wt%, Al2O3≥15 wt%, depleted Y (≤18×10-6 ) and heavy rare earth element contents ( Yb≤1.9×10-6 ), high Sr (rarely<400×10-6 ), negligibly positive Eu and Sr anomalies, and depleted high field strength element contents. They can be generated in different tectonic settings and by different mechanisms. The favorable tectonic settings for the metalliferous mineralization include arc, within-continent extension, and active collisional orogenic belt between different continents. Many large and giant are closely associated with adakitic rocks, indicating that they have a huge metalliferous potential. In the arc and within-continent extension settings, the interaction between subducted basaltic oceanic crust, or sediments, or delaminated continental crust-derived melts, or released super critical fluids with mantle causes contamination of melts by mantle peridotites on the one side, and metasomatism of mantle peridotites by the melts or fluids with high Fe2O3 on the other side. Thus, the raised oxygen fugacity in the mantle causes metal sulfides to be decomposed, which is favorable for the Cu-Au mineralization.
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    Cited: Baidu(47)
    Assessment of Interferences in Cu Isotope Ratio Measurements Using Multiple-Collector Inductively Coupled Plasma Source Mass Spectrometry
    CAI Jun-jun, ZHU Xiang-Kun, TANG Suo-han, LI Shi-zhen, HE Xue-xian
    J4   
    Abstract1328)      PDF (165KB)(1768)       Save
    Multiple-collector inductively coupled plasma source mass spectrometry (MC-ICP-MS) is a relatively new technique for high precision copper isotopic ratio measurements. However, potential interferences may exist in the measurements of ^65Cu/^63Cu ratios. Assessment of the interferences and effects of Cu concentration on the analyses of Cu isotope compositions using MC-ICPMS is presented here. The problem is first investigated by measuring the abundances of Na in the samples to be able to conclude that the isobaric interference of these polyatomic ions is negligible in this study. Secondly, by assuming that there is no interfering signal at mass 63, the anticipated effect of interference at mass 63 on 665 Cu measurement is modeled. The modeling result shows that even the interfering signal is very small, its effect on the ε^65 Cu value can still be between sample and standard is large. Thirdly, by comparison significant when the difference in Cu concentrations of the modeling results and actual measurements, it has been shown that the isobaric interference on mass 63 is negligible. Fourthly, the results of actual measurements show that the true 65 Cu value can be obtained if the Cu concentration of a sample solution is within the range of 0.5 - 4.0 times of that of the standard. Fifthly, the possibility of matrix effects on measured ^65Cu/^63Cu ratios has been investigated. Of primary concern in this study are the effects of Fe and Co contents on the measured ^65 CU/^63 Cu ratio. This has been examined using synthetic mixtures with Fe:Cu and Co:Cu molar ratios ranging from 0.1 to 100, and 0.5 to 10, respectively. Results of these experiments show that there is no clear dependence of ^65Cu/^63Cu on Fe/Cu 〈 100, Co/Cu 〈 7 respectively under the working conditions. Finally, the results of repeated measurements over a period of ten months show that the ε^65 Cu value of the Romil Cu solution obtained from these analyses is 3.5 ±1 (2sd) relative to NBS standard
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    Cited: Baidu(47)
    Characteristics of Zn-Clays Catalysts for Catalytic Ozonation Degrading Process of Dye Wastewater
    YIN Lin
    J4   
    Abstract1008)      PDF (952KB)(846)       Save
    For the difficultly biodegradated organic dye wast ewater, the comparatively ideal experimental results were obtained using Zn- clays c atalysts for multi-catalytic ozonation process. The solid catalysts, made of cl ay carrier and carried Zn oxide, were used to treat the man-made dye wastewat er to raise the catalytic efficiency of ozonation and reduce the costs of trea tment. These solid catalyses can be used repeatedly.
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    Cited: Baidu(42)
    Study on Geochemistry of Rare Earth Elements(REEs)in Permian Coal from Huaibei Coalfield
    ZHENG Liu-gen1, LIU Gui-jian1, ZHANG Hao-yuan1, GAO Lian fen1, XUE Jian1, Chou Chenlin2
    J4   
    Abstract2067)      PDF (3039KB)(810)       Save
    34 samples were collected from coal seams 1 0,7,5,4 and 3 of Permian coals in Huaibei coalfield. The abundances of the rare earth elements(REEs)and other elements in the samples were determined by inductively couple-plasma mass spectrometry(ICP-MS),instrumental neutron activation analysis(INNA)and inductive1y couple-plasma atom emission spectrometry (ICP-AES).The characterizations of the concentration.spacial distribution,geochemical parameters and distribution patterns of REEs are studied.Furthermore.the origin and occurrence of REEs in the samples are discussed.Compared with Chinese coals,world coals and American coals.the REEs are obviously enriched in Huaibei coalfield.The contents of REEs in the coal seams of the Lower and Upper Shihezi Formations are higher than those in the Shanxi Formation. They rise from the bottom to top in thesame coal seam because of the influence of sedimentary environment. According to the values of δCe positive and δEu negative anomalies,and the relationship between the REEs contents with ash yield is the sediments,it can be concluded that the sedimentary environment of the Permian coal in Huaibei coalfield was not influenced by seawater,and the source of REEs is terrigenous matters,and the REEs in coals are mainly concentrated in c1ay minerals such as kaolinite and illite.
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    Cited: Baidu(36)
    New Evidences for Natural Gas Source of Zhujiadun Gasfield
    XU Zheng-long
    J4   
    Abstract1377)      PDF (1452KB)(2044)       Save
    Zhujiadun gasfield is located in Yancheng depression,Jiangsu Province of China. Former researchers believed that gases deposited in the E1-K2t sandstone beds came from the Paleozoic source-rocks,but liquid hydrocarbons in condensate associated with natural gas mainly came from sapropelic kerogen in the Taizhou Formation (K2t). Recent studies on maturity correlation of gases and source-rocks, anatomizing oil-gas mixing, the Paleozoic source-rock outcrop of depression bottom have suggested that high iso-heptane value(5~8)is characteristic for over maturity of the natural gas.Experiments also indicate that the iso-heptane values from the Triassic and the Paleozoic source-rocks areas high as the natural gases,and that iso-heptane values from the Early Tertiary and the Late Cretaceous source-rocks are much louser than the natural gases.Therefore,it is provided again that natural gases originated in the Paleozoic source-rocks. Based on carbon isotopic comparison of ethane and propane in natural gas and pyrolysis gas from source-rocks of various age,it also is suggested that limestone of the Qixia Formation of the Permian is likely a source-rock of the natura1 gas.The distribution of norma1 chain hydrocarbon analyzied recently has“two peaks”structure,but that analyzed two years ago only has one peak for same condensate sample associated with natural gas.The two peaks appeared because frontal peak became louser as the dissipater of light hydrocarbon actually reflect mixing of two source component.The latter peak would be crude oil came from sapropelic kerogen in the Taizhou.Formation(K2t).It is important that a feculence part of condensate has lighter carbon isotopic composition(δ13C-30.5‰)and shows sapropelic feature,but the natural gas has heavier carbon isotopic composition(δ13C2-27‰,δ13C3-25.6‰ )and shows humic feature. According to ananlysis of some hole data,outcrop under the Yancheng depression bottom is southern half of a large anticline and from north to south the formation age gradually becomes yanger.Limestone of the Qixia Formation in the Permian locates southern side of Yancheng depression bottom . The natural gas from source-rocks passed fault No.2 up to pool,and/or sidespin into reservoir from southern side of fault,and fault No.3 plays good side envelop.
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    Cited: Baidu(34)
    Palaeoclimate Changes Recorded by Loess Deposit around Qinghai Lake (Northeastern Qinghai-Tibetan Plateau) since Last Deglaciation
    ZHAO Cun-fa, LU Hua-yu, ZHOU Ya-li, YI Shuang-wen, MASON Joseph
    J4   
    Abstract1861)      PDF (621KB)(1302)       Save
    Loess and aeolian deposits were found in the area around Qinghai Lake. It is well known that loess is regarded as one of the best terrestrial archives of palaeoclimatic and palaeoenvironmental change. However, investigation on the loess and the aeolian deposits, compared with the lacustrine sediments, is limited and weak in this region. In this paper we dated the loess section by the optically stimulated luminescence (OSL) method, and measured the magnetic susceptibility, Fe/Mg value, grain size distribution and organic matter contents of the Heimahe loess profile. Based on the absolute ages and variations of these climatic proxy indicators, our results show that there are clearly warm/cold and humid/arid alternation in Qinghai Lake area since the late deglaciation. During around 14-9 ka, the palaeolclimate was cold and dry, while the climate was better at about 11 ka. A distinct climate ameliorating occurred from 9 ka to 2.5 ka. Strong disturbance by human activity appeared in loess deposit since 2.5 ka, so it is difficult to analyze the climatic change during the latest Holocene. The environmental changes inferred from the loess deposit are in well comparison with the lacustrine records.
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    Cited: Baidu(34)
    Study on Mechanics Experiments of Multiphase Medium Coal Rocks
    FU Xue-hai, QIN Yong, JIAN Bo, WANG Wen-feng
    J4   
    Abstract1282)      PDF (1500KB)(1093)       Save
    Experiments were conducted on natural,water-saturated and water-gas-saturated coal samples to compare their mechanics.The results indicate that elasticity modulus,compression strength and volume compress coefficient of natural coal samples are larger than those of water-saturated coal samples and the latter are larger than those of water-gas saturated coal samples .However,their poisson’s ratios are opposite,and strains of parallel layer direction are larger than that of vertical layer orientation.The swelling experiments demonstrated that coal volume swells when it adsorbs gas and/or water medium ,and the coal rock strength and mechanical energy decreases. It was pointed that coal matrixes will shrink continuously, the coal reservoir mechanical intensity will gradually increase, and the poisson’s ratio and the plane stress ponderance of the covering stratum gravity will decrease,and the coal reservoir permeability may be improved with the discharging of water and gas medium during the coal bed methane recovery in ground wells.
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    Cited: Baidu(33)
    CHARACTERISTICS OF BIDIRECTIONAL SUBDUCTION OF ERLANGPING BACKARC BASIN IN THE EAST QINLING
    Li Ya-lin, Zhang Guo-wei, Song Chuan-zhong,
    J4   
    Abstract1314)      PDF (1769KB)(902)       Save
    The Erlangping back- arc basin was an important part of the North Qinling active continental margin in early Palaeozoic Era. The Erlangplng Group is the remains of back- arc basin, and records its evolution. Analysis of the sedimentary textures demonstrated that the Southern and Northern clastic sedimentary rocks were formed in different active continental margin. Besides, there are two series of subductional granites which distributing along the two boundaries of Erlangping back are basin. Tectonicly, the main orogenic period of deformation can be derided into an early stage and a late stage. Two sets of thrust ductile deformation were formed in early stage while the complex tight folds were formed in late stage. The characteristics of sedimentation, magmatism and deformation all indicate that this back- arc basin is characterized by bidirectional subduction during late Paleozoic Era, i.e., a subduction downward to the Kuanping ancient continent, and another downward to the Qinling ancient island arc.
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    Cited: Baidu(33)
    Chloritization of Qitianling Granite Related to Bailashui Tin Deposit,Southern Hunan Province
    ZHAO Zhan-jie, LU Jian-jun, YAO Yuan, ZHANG Rong-qing, GUO Wei-min, ZHANG Huai-f
    J4    2011, 17 (4): 531-545.  
    Abstract1933)      PDF (5927KB)(1902)       Save

    The Bailashui tin deposit is located in Qitianling Yanshanian biotite granite, Southern Hunan province. Chloritization
    is a universal hydrothermal alteration in this ore-bearing granite. Based on the research of the samples collected from the
    drillhole, we found a notable variation in the chloritized degree of the granite. This study was carried out by selecting three groups
    of granite samples which displayed notable different degree of chloritization. The chloritization nhich closely related to oreforming
    in the Sn-bearing granite had been discussed. The results indicated that, in the granite samples of different degrees of
    chloritization the petrography and chemical composition of chlorite changed with a series of obviously variable characteristics.
    According to the analysis of micropetrography and relevant geochemical data, some conclusions could be drew as follows. Themetasomatic sequence of rock-forming minerals in the granite replaced by chlorite is: amphibole and biotite→plagioclase and
    potassium feldspar→quartz. The variable shape of chlorite was, on the one hand, related to the composition of chlorite; on the
    other hand, related to the crystal texture of rock-forming minerals which were replaced by chlorite. As the chloritization of granite
    was stronger, the LOI and Zn content of whole-rock samples would be higher, and the Cl contents losing to hydrothermal liquid
    from original rock would be more. With the chloritized degree of granite becoming stronger, main compositions of chlorites would
    present regular variations. The Si content of chlorite decreased in the process of chloritization. Al elements were released after
    the breakdown and dissolution of feldspar. The mobilization and redistribution of Al on the thin-section scale increased the
    aluminum content of chlorite. Fe element were brought in to the chrorite by hydrotherm. The amounts of chlorite formed depended
    on how much Fe had been introduced into the hydrothermal system. The Mg for the formation of chlorite was primarily related to
    the redistribution of Mg which was released from mafic minerals. Mn element was mainly brought in to the chlorite by the outer
    hydrotherm.

     

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    The Geochemical Evidences for Existence of Mesoproterozoic Metamorphic Basement in Central Jiangxi Province
    ZHANG Bang-tong1 and HU Gon-ren2
    J4   
    Abstract1517)      PDF (308KB)(1414)       Save
    The whole-rock Sm-Nd isochron age of the amphibolite occurred in the garnet-mica schist from Lean Xiangshan and derived from tholeiitic volcanic rock is 1113±49 Ma. In combination with the isotopic dating results of amphibolites in Yiyang Meishuwan and Yijiang Maquan ((1159±69 Ma,Sm-Nd; 1190±19Ma, U-Pb respEctively ), it is confirmed that the original rocks of central Jiangxi metamorphic belt belong to Mesoproterozoic strata. By means of fuzzy cluster analysis on trace element geochemical ratio between Chencai Group in west Zhejiang,Sinian System and metamorphic rock in Jiangxi, in combination with the Pb-Nd isotope geochemical features of amphibolites,it is identified that the central Jiangxi metamorphic belt is closely correspond to the Chencai Group and belongs to Cathaysian block. On the basis of a detailed comparative study on the deep geophysical features of gravitation and magnetic fields and the distribution of stratra and magmatic rocks on both sides of the Congren-Linchuan-Dongxiang Cretaceous red-bed fault basin, it is inferred that the northwest boundary of Cathaysian block may be limited by the Suichuan deep fault.
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    Influence of Microbe-Mineral Contact Model on Mineral Dissolution: A Primary Study on Microperthite Dissolution by Paenibacillus polymyxa
    ZHOU Yue-fei
    J4   
    Abstract1255)      PDF (921KB)(1183)       Save
    Microorganisms can promote the dissolution of silicates by direct and indirect mechanisms. The contribution of both mechanisms to the mineral dissolution varies with the growth stage of microorganisms. By employing microfiltration membrane, this research tried to illustrate the contributions of these two mechanisms to dissolution of microperthite. The results showed that during 96 hours, culturing, Paenibacillus polymyxa and its metabolites can promote dissolving microperthite both by direct and indirect mechanisms. The direct mechanism can promote releasing Al, but has little effect on K and Si, which are considered to be mainly released by indirect mechanism. Direct and indirect mechanisms both show intense effects in stationary and dead phases. During mineral dissolution, consumption of bacteria growth and complexation of bacteria and metabolites are also important factors influencing the concentration of elements. Furthermore, the synergetic effect complicates the ion concentrations.
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    Cited: Baidu(29)
    A Review of Tellurium Minerals
    QIAN Han-dong, CHEN Wu, XIE Jia-dong, HUANG Jing
    J4   
    Abstract1115)      PDF (2162KB)(904)       Save
    This paper preliminary summarises 172 tellurium miuerals which have been reported in literatures and formally approved by the Commission on Minerals and Mineral Names (CNMMN) of the International Mi neralogical Association (IMA). A list of these minerals is given as a table. The major element chemical compositions, geochemical features, geochemistry and mod es of occurrences of tellurium minerals, and the achievements acquired in tellur ium mineralogy of China are reviewed. Finally the problems concerning the furthe r studies of tellurium mineralogy and geochemistry are also discussed.
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    Cited: Baidu(27)
    Preliminary Study on Fluid Inclusion Planes for Dabie Mountain Granite
    NI Pei, FAN Jian-guo, ZHOU Jin, DING Jun-ying, MA Dong-sheng, HUA Ren-min,, LING Hong-fei, JIANG Shao-yong
    J4   
    Abstract2216)      PDF (2395KB)(1381)       Save
    The devolvement and migration of geo-fluids is controlled by regional stress.Fluid inclusion planes(FIP)are a bridge to link the geo-fluid and the stress.It is a useful means to investigate the migration of the geo-fluid under certain regional stress field.Fluid inclusion planes kept in the granites provide the best way for US to study the regional stress field change and the fluid evolution when the granites intrude into the country rocks and cool down at the crustal environment.This paper statistically surveys FIPs attitudes for three granitic intrusives in Dabie Mountain,Anhui province(Zhubeyuan,Tianzhushan and Sikongshan granites).Microthermometric works were also done on the fluid inclusions in FIPs.It is revealed that the characteristics of FIPs in the Zhubeyuan and Tianzhushan grantes are similar ,but obviously different from the Sikongshan granite.The FIP in Zhubeyuan and Tianzhushan granites have preferred orientations of NE and NW W .The NW W striking FIP are cross-cut by the NE striking FIP.The homogenization temperature, salinity and CO2 contents of the fluid inclusions in NW W striking FIP are higher than those of NE striking FIP, which indicate regional paleo-stress change from NWW to NE strike accompanying the intrusion and cooling of the above two granites,and fluids evolved from CO2—H2O-NaC1 type to H2O-NaCl type with declined temperatures and salinities.FIP in Sikongshan granite have preferred orientations of SN and EW .The EW striking FIP are cross-cut by the SN striking FIP.While cooling, the Sikongshan granite experienced a regional stress field changing from EW to SN and fluid types changing from CO2-CH4-H2O-NaC1 type to H2O-NaC1 type with the declined fluid temperatures and salinities.
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    Cited: Baidu(27)
    Origin of Coalbed Methane in Baode, Northeastern Ordos Basin
    J4    2012, 18 (3): 479-.  
    Abstract613)      PDF (1170KB)(1232)       Save

    Trial coalbed methane (CBM) production of the well group in Baode has achieved a relatively satisfactory result but the
    CBM genesis is still unconfirmed. Based on the data of the components and stable isotope composition of the CBM sampled from
    the producing wells, the genesis was discussed. Results showed that the CBM is mainly composed of the methane with little heavy
    hydrocarbons. Carbon isotopic composition of the methane is obviously light, and partial data of the carbon and hydrogen isotopes
    of the methane plot within the transitional range between the thermogenic and biogenic gases. Carbon isotopic composition of the
    carbon dioxide of the samples is relatively heavy and is negatively correlated to the carbon isotopic composition of the methane. It
    was suggested that the coalbed methane in the area has a mixed thermogenic and biogenic origin, but thermogenic gas is the main
    with composition minor of biogenic gas. Biogenic methane was formed through the reduction of carbon dioxide. The chemistry
    and hydrodynamics of the coalbed water and the porosity and permeability of the strata in the area were favorable of the active
    population of the methanogenic bacteria.

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    Characteristics of pH Variation in the Cr(VI)-bearing Wastewater Disposed by Clino-Pyrrhotite and Hexa-Pyrrhotite
    LU Xiao-ying, LU An-huai, CHEN Jie, TANG Jun-li, YAO Zhi-jian
    J4   
    Abstract1521)      PDF (1389KB)(1058)       Save
    The content of Fe in the structure of clino-pyrrhotite is l ower than that in the structure of hexa-pyrrotite. The experiments have been ma de to measure the pH variation of the Cr (VI) - bearing wastewater after treatment b y clino-pyrrhotite and hexa-pyrrhotite respectively. The initial pH values are 3 .40~9.66 and 3.47~9.66 respectively; while after treatment, the pH values beco me 3.61~4.47 and 5.39~6.57 respectively. The disposal efficiency of Cr(VI) by c lino-pyrrhotite is higher than that by hexa-pyrrhotite. However, the disposal ef ficiency of Cr(VI) increases with the oxidized hexa-pyrrhotite. Electro-chemic al analysis shows that increase of pH values in acidic media and decrea se of pH valus in basic media during redox reaction are beneficial to practical disposal due to consuming H+ in acidic media and combination of Fe(II) with OH - in basic media which are also verified by the experimental results.
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    Cited: Baidu(27)