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    20 March 2006, Volume 12 Issue 1
    Article
    A Comparison Study of Basin and Range Tectonics in the Western North America and Southeastern China
    SHU Liang-shu, WANG De-zi
    2006, 12(1):  1-13. 
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    The basin and range tectonics in both western North America and Southeastern China are a distinctive geologic and geomorphologic scene.Their formation and evolution possess profound geologic settings and tempral-spatial-material conditions. This paper studies the geologic setting, tectonic units and tectono-magmatic assemblages, basement and deep-seated structures, temporal-spatial relation, formation mechanism, coupling patterns and evolutional history of basin and granitic ranges in these two regions, analyzes the geometry, petrography, geochronology and petrogenesis of metamorphic core complexes in the two basin and range regions. Our studies suggest that some principal similarities occur in the basin and range zones on both sides of Pacific Ocean, including(1)Two regions belong to Pacific tectonic regime during Mesozoic-Cenozoic and are controlled by Pacific system;(2)The beginning time influenced by Pacific plate subduction is the same, the Middle Jurassic,with close width of active continental margin;(3)The time of subduction angle change from gentle to steep is the same, about 100 Ma, which further caused back-arc extension-collapse tectonics and lithospheric thinning; (4) The Cordilleran-type extensional tectonics and metamorphic core complexes are developed well in both regions; (5) The extensional basins and granitic ranges in both sides of the Pacific share similar forming geotectionic setting,their spatioal coupling and genetic relation. At the same time, some differences exist in these two regions, including (1) difference in magmatic assemblages; (2) difference in forming age of basin and range tectonics; (3) difference in activity of mantle plume; (4) difference in migration of subduction zone; (5) difference in solidification degree of basement and metamorphic core complexes .
    The characteristics of HuaYuan-ZhangJiajie Fault belts and ESR dating of WuLing Mountain, in western HuNan
    Xie Jianlei, Yang Kunguang, Ma Changqian
    2006, 12(1):  14-21. 
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    As an important fault belt in the northwestern XueFeng uplift zone, the movement history of Huayuan-Zhangjiajie fault belt carries much information about the revolution of uplift zone. By a comprehensive research of macrostructure, microstructure, ESR (Electron Spin Resonance) dating and temperature measuring of fluid inclusion, a conclusion can be drawn that it underwent a comprehensive revolution process which includes several times of compression, extension and compression sliding. It is shown that the active intensity in the northern part was stronger than in the southern part. Since the Mesozoic era, the deformation was brittle in the shallow crust and accompanied with more than once low temperature hydrothermal activities. Temperature measuring of fluid inclusions indicates that homogeneous temperature mainly concentrated in three intervals of 120-150℃、180-200℃ and 270-330℃. The Quartz ESR (Electron Spin Resonance) dating of fault belts demonstrates that its intense movement occurred in the period of latest middle Yanshanian and late Yanshanian (86-131.8Ma). According to the field occurrence and character of the quartz veins, combining with published data, a conclusion was drawn that the transformation time from compression to extension took place between 131.3Ma and 120Ma in Mesozoic era, up to 110Ma or so, extension became intensive.
    The Thrust Deformation of Pluton:Take the Jinfosi Plutonin Eeasten Jiuquan Basin as an Example
    WU Jianyong, TANG Qisheng, CHEN Hanlin, XIAO Anchen, CHENG Xiaogan, MAO Qiming
    2006, 12(1):  22-29. 
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    This paper analyzes the thrust deformation features of the Jinfosi pluton in the eastern Jiuquan Basin which were controlled by the effect of late regional structure, and presents the deformation mode of the pluton, by investigating the field deformation features and interpreting the seismic profiles which passed the pluton. The authors consider Jinfosi pluton was influenced by intensive thrusting action,and the average distance of thrusting was more than 15km.Controlled by the main thrust fault and secondary thrust faults, the interior pluton had been deformed intensively,and a complex fault-propagation fold was formed.Under the main thrust fault is a part of the Mesozoic and Cenozoic foreland depression of Jiuquan Basin,had been changed into a fault-propagation fold Cenozoic foreland depression of Jiuquan Basin.
    Late Mesozoic and Paleogene Basalts and Deep-Derived Xenocrystsin Eastern Liaoning Province,China:Constraintson Nature of Lithospheric Mantle
    WANG Wei, XU Wen-liang, JI Wei-qiang, YANG De-bin, PEI Fu-ping,
    2006, 12(1):  30-40. 
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    The K-Ar dating results of basahs in eastern Liaoning Province indicate that Qujiatun and Luanshishanzi basahs were formed in the Late Cretaceous with an age of 81.58 4±2.46 Ma and in the Paleogene with an age of 58.36±1.64 Ma,respectively.Abundant deep-derived xenocrysts such as olivine,clinopyroxene,and hornblende have been found in the basalts.The olivine xenocrysts from Luanshishanzi basalt have higher Mg# values (79.5-88.5,ave.84)than those from Qujiatun basalt(77.0-79.8,ave.78.4).The clinopyroxene in basalts is diopside,whose change trend in Mg# etc.from nuclear part to periphery is similar to that of olivine.The orthopyroxene in basalts is bronzite with the Mg# values of 85.2~87.6(ave.86.4).The circle cracks,kink bands,compositionzoning,and equilibrium of Mg# values between olivine xenocrysts and host basahs imply that the xenocrysts could be the earlier magmatic cumulate caught by the host basaltic magmas.The petrological and geochemical data of the basalts show that(1)they are alkaline basalts,but the Qujiatun basalts are higher in CaO and A12O3,lower in SiO2 and MgO than the Luanshishanzi basalts (2)they have similar REE distribution patterns,but the Qujiatun basahs have higher REE abundances and LREE/HREE ratios than the Luanshishanzi basalts;(3)they have similar Sr-Nd isotopic compositions.The Isr and εNd(t)values are 0.7039~0.7045 and+1.60~+3.69,respectively.It implies that they could be derived from the depleted lithospheric mantle.
    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
    2006, 12(1):  41-52. 
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    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.
    Petrology-Mineralogy and Classification of Eleven Ordinary Chondritesfrom the Grove Mountains in Antarctica
    LIANG Ying, WANG He-nian, JI Jun-feng
    2006, 12(1):  53-61. 
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    Analyses on eleven meteorites recovered from the Grove Mountains in Antarctica indicate:all themeteorites have chondritic textures and are identified as ordinary chondrites.In this paper,their petrography and mineralogical chemistry are studied,and their chemical groups-petrologic types are classified,including four Hchondrites,six L chondrites,and one LL chondrites.Especially GRV 020010(LL3)and GRV 021481(H3)are unequilibrated ordinary chondrites,and rare and vacant unequilibrated meteorites in Chinese meteoritic reserves.Moreover,their magnetic susceptibility is measured,and the role of magnetic susceptibility in the classification of chemical groups of meteorites is also discussed tentatively.
    Petrological and Geochemical Characteristics of the CarboniferousVolcanic Rocks,South of the Xinyuan County,Xinjiang
    GUO Xuan, ZHU Yong-feng
    2006, 12(1):  62-73. 
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    The Xinyuan volcanic rocks in western Tianshan mountains mainly consist of basahs,basaltic trachyandesites,trachyandesites,andesites,rhyolites and pyroclastic materials.The basahs constitute calcalkaline association,whilst the andesitic rocks and rhyolites belong to high-K calcalkaline series.The REE patterns indicate thatLREES are slightly enriched and HREES are comparatively depleted in the studied volcanic rocks.In the primitive mantle-normalized trace element diagrams, basahs show LILE, U,Th and Pb enriched patterns with HFSE troughs.This study displays that the volcanic magma probably came from the partial melting of the mantle wedge,which had undergone metasomatism induced by the subduction fluid.According to calculation,3 to 6 percent partial melting of garnetlherzolite could produce the basalt magma.The andesitic magma could be produced by the fractional crystallization of basalt magma,the fraction of which is 15 to 28 percent.
    U-Pb Geochronology and Tectonic Setting of the Granitic Gneissin Jianggaleisayi Eclogite Belt,the Southern Edge of Altyn Tagh
    WANG Chao, LIU Liang, CHE Zi-cheng, CHEN Dan-ling, ZHANG An-da, LUO Jin-hai
    2006, 12(1):  74-82. 
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    Geochemical studies on the Jianggaleisayi granitic gneiss suggest that the rocks are characterized by SiO2>70% ,Al20 3>13% ,Na2O +K2O =7.52% ~8.91% ,and with ASI=1.10~ 1.27,belonging to syn-eollisional S-type granite.The chondrite-normalized REE patterns are right-inclined,with a clear"V"trough,belonging to the granite of crustal source.The midocean ridge granite-normalized trace element spidergrams are characterized bv enriched LILE(such as Rb and Th)and depleted HFSE(such as Nb,Zr,Hf,Y,and Yb).0n the R1~ R2 tectonic discrimination diagram they are plotted in the typical continent-continent syn-collisional granite field.The CL investigations reveal that zircons from the granitic gneiss are generally colourless,transparent and eu'hedral。and have distinct zoning of oscillatory bands,typical of magmatic origin.By means of LA-ICP-MS U-Pb isotopic dating.the zircons yielded a weighted average 206Pb/238U age of 923±13(2σ)Ma and indicative of Neoproterozoie time.Combined with the Neoproterozoic syn-collisional granite obtained from adjacent area,it is suggested that a collision and convergence between microcontinents in NW China took place during the Neoproterozoic time.This is very important not only for determining the existence of Neoproterozoic orogeny and for reconstructingthe tectonic evolution of the ancient continents in northwestern China,but also for providing constraints for discussing the relationship between the HI 一UHPM rocks and their country gneisses in the study area.
    Geochemical and Genetic Characteristics of Selenium Ore Depositin Shuanghe,Enshi,Hubei Province
    ZHENG Xiang, QIAN Han-dong, WU Xue-mei
    2006, 12(1):  83-92. 
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    The relatively low SiO2 and high A12O3,K2O,TiO2,MgO values and the ratios of SiO2/A1203,SiO2/MgO,SiO2/(K2O+Na2O)of the seleniferous rocks in Shuanghe are similar to those of the volcano-sedimentary cherts.As seen in the TiO2-A12O3 and(K2O+Na2O)一A12O3 diagrams,the data points mainly fall within the field of volcano-sedimentary cherts.The ratios of A1/(A1+Fe+Mn)(0.72 in average,with a maximum of 0.93)are higher than the values of the biogenetic siliceous rocks.The extreme enrichment of Se,Te,Mo and high contents of V,Ag,Sb,Cr also show some igneous characteristics.It is more important for the first time to discover the argillized pyroelastie breccia in the interlayers of seleniferous rock in Yutangba digging.The data points of the seleniferous rocks in P2 05一Y correlation diagram along with the ratios of Co/Ni< 1 and U/Th > 1 all show some hydrothermal characteristics.REEs are characterized by total similarity inΣREE concentration with Emeishan basalts,relative enrichment in HREE,negative Ce anomaly and gradually increasing NASC-normalized value with increasing atomic number of REEs.Generally,it can be judged from the analytical results of major elements,trace elements and REEs that the genesis of the seleniferous rocks in Shuanghe was closely related to the Permian volcanism synchronous with eruption of Emeishan basalts and belonged to the volcanic detrital sediment and accompanied by the hydrothermal activity.
    Isolation of a Strain of Acidithiobacillus ferrooxidans from Yunfu SulfideMine in Guangdong Province and Studies on Its Growth Rule
    JIANG Lei1 2, ZHOU Huai-yang1, PENG Xiao-tong1
    2006, 12(1):  93-97. 
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    A strain of Acidithiobacillus ferrooxidans Y1 was isolated front acid mine drainage in Yunfu sulfide mine in Guangdong Procince.antd its growth rule was prelinminarily studied.The results show that negative correlation exists between the cell numbers and the ferrous concentration in culture medium along with time.which indirectly proves that Acidithiobacilluts ferrooxidans obtained energy through oxidating ferrous.When ferric iron concentration was high enough in the solution,jarosite was produced.In this process,the pH value of the solution became larger firstly and then smaller, always maintains in the range of 2.0~2.5.
    The Putative¨Radiolarian Cherts¨from Ophiolitic and MetamorphicComplexes in Northeast Jiangxi:A Re-examination
    WANG Yujing1, YANG Qun1, YIN Lei-ming1, SHU Liang-shu2, LOU Fa-sheng3, WANG Bo2
    2006, 12(1):  98-105. 
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    The age assignment of the putative radiolarian cherts from the ophiolitic/metamorphic complexes in northeast Jiangxi is widely regarded as one of the crucial issues in the tectonic interpretation of South China. Traditionally,these ophiolitic/lightly metamorphic complexes have been regarded as part of the Proterozoic"Banxi (=Penhsi)Group"of the Jiangnan Uplift.However,recent reports of late Palaeozoic radiolarians from the rock complexes have caused some researchers to question the traditional interpretation of the tectonic and palaeogeographic framework in the region,though other workers are suspicious about these findings. In order to test the reality of the putative radiolarians,we,an interdisciplinary study group including micropalaeontologists,tectonic specialists and regional geologists,conducted field investigations and multiple resamplings of the localities where the reported lossils were collected.We also reanalyzed the published materials of the above mentioned new findings.Our study shows that the putative radiolarian-bearing chert of the ophiolitic complex and the low-grade metamorphic strata do not yield any identifiable radiolarian fossils,although Mesoproterozoic and Neoproterozoic aeritarehs are diseovered from them.Geochemical characteristics such as the element composition, Ce anomaly,La/Ce ratio and trace e1ements indicate that the chert sedimentation is closely related with a terrestrial provenance. a setting far away from the deep oceanic settings.Because our investigation has not verified the Palaeozoic radiolarian findings,five probable causes for the radiolarian reports are discussed.
    Globular Sponge Fossils from the Lower Cambrian in Songlin,Guizhou Province,China
    ZHAO Yuan-long1, YANG Rong-jun1, YANG Xing-lian1 2, MAO Yong-qi1
    2006, 12(1):  106-110. 
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    The Niutitang Biota from the lower Cambrian in Songlin Town,Zunyi County,Guizhou Province,southwestern China is dominated by sponges and represents early radiation of sponges in early Cambrian.Two common sponge genera were found in the lower horizon of the Niutitang Boita.They are Triticispongia(Mehl et Reinter),1993 and Saetaspongia(Mehl et Reinter).1993.Body wall of the former is composed of two kinds of stauractin of different sizes.which are mainly in diagonal arrangement.The body wal1 of the latter is composed of dense accumu1ations of hairlike diactines.Spicules in these two genera do not protrude out of body wal1.Sponge body of both genera hardly exceeds 10 cm in size.They belong to Hexactinellida.Both genera were firstly found in black shale of the lower part of the Niutitang Formation,Sancha Town,Dayong,Hunan Province,and then in the Niutitang Form ation in Zunyi,Guizhou Province.
    Lithofacies PaIeOge0graphic Constraints of SouthwesternBoundary between Yangtze and Cathaysian Plates in Caledonian
    CHEN Mao-hong1, LIANG Jin-cheng2, ZHANG Gui-lin2, LI Wen-jie2, PAN Luo-zhong3, Li Rong-shen3,
    2006, 12(1):  111-122. 
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    Quantitatire lithofacies palaeogeoaphic analysisis can provide constraints to boundary of different geotectonic units. By means of the method of "single factor analysis multifactor comprehensive mapping",integrating several aspects of data such as palaeo-current directions and sedimentary charateristics,a quantitative study is made on the Caledonian lithofacies palaeogeography of NE Guangxi.Since the Neoproterozoic,the whole research area cracked into two different basins along the Lipu fault.0n the NW side of the Lipu fault (N and NE Guangxi),The Caledonian basin evolved from deep-sea basin to passive continent margin basin.Its slope dipped to the southeast,and palaeo-current directions were from northwest to southeast.The terrigenous detrital sediments were derived from the northwest.However,on the SE side of the Lipu fault(E Guangxi),the Caledonian basin had long been an active continent slope environment.and eventually evolved into a continenta1-shelf-coastal environment in the Ordovician.The slope dipped to the northwest.and the palaeo-current directions were from southeast to northwest.The terrigenous detrital sediments were derived from southeast.A1l these indicate that they belonged to different palaeogeographic systems.That is,the basin in northern and northeastern Guangxi belonged to the Yangtze plate,while the basin in eastern Guangxi belonged to the Cathaysian plate. The proof of lithofacies paleogeography suggests that the Lipu Fault is a dividing fracture which separates two terrains in the Caledonian.
    Complex Resistivity Dispersion Properties Experiment of Shaly Sands
    XIAO Zhan-shan1, XU Shi-zhe1, LUO Yan-zhong2, WANG Dong3, ZHU Shi-he3,
    2006, 12(1):  123-130. 
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    Experimenta1 research of dispersion properties on shaly sands with different fluid properties is the petrophysical basis to evaluate the water cut or low resistivity oil-bearing formation using complex resistivity logging technique.The experimental research has been carried on the complex resistivity dispersion properties of water flooding for water,for oil and oil flooding for water.The results indicate that the influence of oil saturation on dispersion is significant and the influence of the formation water salinities is smal1.Especially,the influence of water salinities on the quadrature resistivity is negligible.Corresponding to water bearing shaly sands,the CRL phase ange1 of oil-bearing shaly sands is large. Meanwhile,it increases with the increasing oil saturation. The dispersion properties of water-bearing formation and oil-bearing formation are different.Therefore,the experimental results of dispersion properties of shaly sands show that the formation oilness can be identified effectively by complex resistivity logging developed based on the dispersion properties of the rocks.
    Destruction Types and Mechanism of Hydrocarbon Reservoirsin the Western Qaidam Basin
    LIU W ei-hong1 2, GUO Ze-qing2, LI Ben-liang2, RAO Meng-yu1, WEN Zhi-feng1, YANG He-shan1
    2006, 12(1):  131-141. 
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    Destruction of hydrocarbon reservoirs is an inevitable process due to temporal and dynamic variability inherited in any kind of hydrocarbon accumulation which is susceptible to certain geologic factors in the geologic time.According to the history of tectonic evolution and reservoir formation in the western Qaidam basin,the period from late Pliocene to Quaternary is responsible for the destruction of primary reservoir and the formation of secondary reservoir,There are many types of oil and gas shows on the ground,such as oil sand,pitchy,paraffin,mud volcano and oil hillock.Analysis on geological factors causing the destruction of hydrocarbon reservoirs shows that fault movement,hydrocarbon reservoir uplift and abnormally high pressure are the main types for the destruction of hydrocarbon reservoirs.Furthermore,the destruction of hydrocarbon reservoirs is a synthetic action by fault movement and hydrocarbon reservoir uplift,The study played certain role in guiding oil-gas exploration work in the western Qaidam.
    Application of the Reservoir Trap Size Sequence Methodto Resource Assessment of Shengtuo Area
    YAN Ke1, XU Shou-yu1, CAI Chuan-qiang2, GUO Zhen-hai2, CUI Zhi-kun2
    2006, 12(1):  142-146. 
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    Being developed for more than forty years,Shengtuo area has come into the advanced exploration degree stage.In order to study the size and distribution of the undiscovered reservoirs in Shengtuo area,the reservoir trap size sequence method is applied to evaluate its remaining resource potentia1.The studies show that there are still 124 undiscovered reservoirs whose reserves in every pool are greater than 30×10 4t and the quantities of total remaining resource are about 1.46×10 4t.Not only did the undiscovered reservoirs include small-scale pools of which sizes are smaller than 1O0 ×10 4t,but also 35 large.scale ones of which total reserves are 9672×10 4t.The quantities of the remaining resources and the undiscovered reservoirs of Shengtuo area,forecasted by reservoir size sequence method,can play an important role in finding out the optimum direction of exploration and guiding the future exploration of this area.
    An Analysis for Common Logical Mistakes in Geological Studies
    ZHANG Yu-xu
    2006, 12(1):  147-152. 
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    For the particularities in geological studies,that is,generally one can only deduce causes from observed effects,the logical references have very important meaning.However,in geological academic theses,logical reasoning mistakes can often be found,such as indistinct not clear definition,incomplete inducing,inappropriate inducing,inappropriate matching,unreasonable inferring,setting the cause and the effect inversely,recycled definition or argument,etc.