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    25 October 2014, Volume 28 Issue 5
    Petrology and Study of Ore Deposits
    Zircon Dating of Early Paleozoic Adakitic Granite on the Northern Margin of Qaidam Basin and Its Geological Significance
    ZHOU Bin,ZHENG You-ye,TONG Hai-kui,XU Rong-ke,NIE Xiao-liang,MA Chao
    2014, 28(5):  875-883. 
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    The Tieshiguan rock mass, located at the west-central segment of the northern margin of Qaidam basin, is composed of adakitic granite that was recently discovered in this area. The granite has high contents of SiO2(71.36% to 73.70%), Al2O3(14.48% to 15.64%), and low content of MgO(0.44% to 0.71%); the trace elements display adakitic affinity, which are characterized by strong enrichment of Sr(>350×10-6), depletion of Yb(0.67×10-6-1.58×10-6) and Y(6.74×10-6-18.02×10-6), and high ratio of Sr/Y(21.32 to 72.49), enrichment of LREE and LILE, and depletion of HREE and HFSE. The Tieshiguan granite has 206Pb/238U weighted mean age of (422.0 ± 6.4)Ma, representing the magma formation age Studies have shown that the Tieshiguan granite is most likely formed by re-melting thickened continental crust in post-collisional orogenic stage.

    SHRIMP Zircon U-Pb Dating of Xianlin Granodiorite Rock in Western Zhejiang and Their Geological Significance
    TANG Zeng-cai,DONG Xue-fa,HU Wen-jie,MENG Xiang-sui,RONG Yi-pi
    2014, 28(5):  884-892. 
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    Geological characteristics show that the Xianlin iron-molybdenum ore deposit belongs to the skarn type and it is formed from the contact replacement of the postmagmatic hydrothermal solutions. There are closely relationships between the formation of the deposit and granodiorite magmatic hydrotherm. According to the altered rocks, ore structure and mineral assemblage, the deposit formation is divided into 4 mineralization stages. The zircon SHRIMP U-Pb dating results indicate that the Xianlin granodiorite were emplaced at (151.8±2.2) Ma, and the Re-Os isotopic age of molybdenite shows that the mineralization took place at (132.05±0.47) Ma. The two ages prove that mineralization events occurred in Late Jurassic and Early Cretaceous, and constraint the time of the rock- formation→mineralization, which represents the time domain of mineralization process of skarn iron-molybdenum ore-forming system in the Xianlin of Western Zhejiang.

    Characteristics of Ore-forming Fluids from Zhesang Gold Deposit in Funing County,Yunnan Province
    DAI Hong-zhang,CHEN Cui-hua,GU Xue-xiang,LI Bao-hua,DONG Shu-yi,CHENG
    2014, 28(5):  893-904. 
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    Based on the petrography, micro-thermometry, REEs data, hydrogen and oxygen isotopes of the fluid inclusions in the Zhesang gold deposit in Yunnan Province,we discussed the characteristics of the ore-forming fluids. The results show that there are four types of fluid inclusions, which includes liquid inclusions, pure liquid inclusions, pure vapor inclusions and CO2-bearing three-phase inclusions. Homogenization temperatures, salinities, densities and mineralization pressures of liquid inclusions are 83.4-248.2 ℃, 0.18%-6.45%, 0.85-1.0 g/cm3 and 10.9-59.4 MPa, respectively. Metallogenic depth which is calculated based on the above data ranges among 0.2-2.2 km. REEs data of quartz and calcite from different hydrothermal stages display that the Zhesang gold deposit formed in reducing environment. δ18OH2O of the fluid inclusions ranges from -6.1‰ to 4.9‰ and the δDV-SMOW ranges from -40.3‰ to -74.8‰, showing that the ore-forming fluid comes from atmosphere precipitation. When the ore-forming fluid flowed through the organic-rich sedimentary rocks, primitive mefeoric water would be contaminated by the organic substance, resulting in the drift of hydrogen isotope. Organic carbon content of the ores reaches 0.12%-0.45% and the Au grade is growing with the increase of organic carbon. The δ34SV-CDT values of pyrite and arsenopyrite range from 9.2‰ to 10.2‰. All these evidences proved the source of sulfur resulting from the reaction between organic matter and sulfate in wall-rocks. Preliminary analyses inferred that during the oozing process, the ore-forming fluid mixed with the construction water and was heated to recycle upward by magma and geothermal gradient. Gold mineralization occurred in interaction process between the thermal recycle and wall-rocks, and enriched in proper space.

    Geochemical Characteristics of Uranium Mineralization Rock in Baimadong, Kaiyang County, Guizhou Province
    YANG Rui-dong, REN Hai-li, LIU Kun, GAO Jun-bo
    2014, 28(5):  905-914. 
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    Baimadong uranium deposit is an important alteration-type uranium deposit. On the basis of the research and analysis on major elements, trace elements and REE compositions of Qingxudong Formation black altered rock in Baimadong, weathered red clay from dolomite and Cambrian black shale, a positive correlation in concentration was found between uranium and Re, Se, Pb, Cu, As, Sb, Tl, Zn, Ni, Mo, Co, S. The content of Re, Se, Pb, Cu, As, Sb, Tl, Zn, Ni, Mo, Co, S increases with the increasing of uranium content, of which uranium and As, Co, Mo, Ni, Re, Se, Tl, Zn, S show dramatic positive correlation. Se, V, Mo concentration in soil was considered as one of the main attributes to prospect uranium deposits. According to the analysis of REE distribution pattern among Qingxudong Formation in Baimadong, Cambrian black shale and silicified dolomite of Dengying Formation, material source of Se concentration and uranium mineralization were not only originated from Niutitang Formation, but also possibly from deeper material source. Therefore, the Se concentration area is probably the area that uranium deposits are located in. The ancient slag from mercury smelting concentrates uranium, which is also worth exploring and treating.

    Geochemistry,Ore Deposits and Petrology
    Eco-geochemical Survey and Assessment in Pearl River Delta Economic Zone, Guangdong Province, China
    DOU Lei ,DU Hai-yan,YOU Yuan-hang,LAI Qi-hong,
    2014, 28(5):  915-927. 
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    Soil heavy metal pollution is one of the main environmental problems in Pearl River Delta Economic Zone, which directly threatens the stability of regional ecosystem and food safety, and has profound influences on economic sustainability, especially for sustainable agriculture and people’s health. Consequently, soil environment quality and food safety in this region have receiving extensive attention from all around China. Based on multi-purpose regional geochemical survey, regional eco-geochemical assessment, local eco-geochemical assessment and comprehensive appraisal, the eco-geochemical survey and assessment in Pearl River Delta Economic Zone of 47,954 km2(including the area of 10 m depth in shallow inshore waters) was completed. Samples of soil, sediments of intertidal and major rivers in the region were collected in accordance with the two-layer grid method.Totally 71 elements and indicators for soils and sediments were determined and it is the first time to study the geochemical characteristics of the Pearl River Delta region. On the basis of the regional survey,the samples of rock, soil, sediment, dust, water, biology, human hair and other types of media samples in significant zone were systemic collected.The composition, distribution characteristics, sources, impact mechanisms and ecological security, migration and transformation process of toxic elements and nutrition elements in significant zone were investigated through case research and general analysis. According to the characteristics of the area, we firstly carried out the study of geochemical character of delta formation evolution and formulation of environmental quality standards for soils in the Pearl River Delta region.

    Geochemical Characteristics of Selenium in Taishan Region of Pearl River Delta
    LIU Zi-ning,DOU Lei,YOU Yuan-hang
    2014, 28(5):  928-934. 
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    Taishan region is located in the southwest of Pearl River Delta, Guangdong Province. Through different types of rocks,soils and crops were systematically sampled; geochemical characteristic of selenium, source of selenium in soils, and prospects of selenium-enriched agricultural products in this area were studied. The results show that the selenium contents is closely related to lithology and strata, and that content in the Upper Cambrian Shuishi Formation is the highest. The content level of lithology is in the order of epimetamorphic mudstone, argillaceous siltstone, tuff, granite. There are abundant selenium with the surface soil in the area, but distribution of selenium in different parent materials soil profile was significantly different. Selenium in soil profile of epimetamorphic mudstone parent materials was enriched in the bottom, but the sandstone occurred in topsoil layer, while the granite parent materials occurred in the middle illuvial horizon. Magmatism selenium providing, the regional shallow metamorphism activation and enrichment,and clay mineral adsorption cause rich selenium contents in soils in Taishan region. Neither the addition of exogenous selenium nor soil improvement, the selenium contents of corps in the area for more than 40% has reached the requirements for selenium-enriched contents standard of agricultural products, indicating an alluring prospects for the development of seleniumenriched agricultural products.

    7Characteristics of Spatio-temporal Variability of Soil Mercury in Beijing Urban for 24 Years
    HUANG Yong,YANG Zhong-fang,FENG Hui,SUN Zhao
    2014, 28(5):  935-941. 
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    Temporal and spatial variability characteristics of soil mercury content in Beijing urban for 24 year interval (1987—2011) were evaluated using geostatistics and geographic information system(GIS). Results indicate that there is remarkable change that soil mercury content presents obvious decline along with temporal process because of the Energy Consumption Structure’s change of Beijing City. From 1987 to 2005, soil mercury content decreased markedly in the study area mainly because of energetically implementing the measure of factory relocation and Coal to Gas. The average content of soil mercury decreased from 1.291 μg/g to 0.556 μg/g. But there is slight change that soil mercury content decreased from 0.556 μg/g to 0.490 μg/g in the period of 2005—2011. The range of high value area of soil mercury content is reducing within the second ring road of Beijing from 1987 to this day. From 1987 to 2005, soil mercury within the second ring road showed visible depletion that soil mercury content decreased by more than 1 μg/g. After 18 years the area of Grade Ⅲ and over Grade Ⅲ standard diminished from 142.22 square kilometers to 53.59 square kilometers. Compared with 2005, only soil mercury in the area of north-central part within the second ring road and southwest within the third ring road has relatively significant depletion in 2011 that soil mercury content decreased by more than 0.3 μg/g. The area of Grade Ⅲ and over Grade Ⅲ standard has diminished to 40.51 square kilometers after 6 years.

    Comparative Studies on the Geochemistry Anomaly Extraction in Baiyinguole Area, Inner Mongolia
    KUANG Zhu-hua,ZHANG Hao-ran,LIU Wen-can
    2014, 28(5):  942-952. 
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    How to extract geochemistry anomalies reasonably is the fundamental question in the field of exploration geochemistry which is the key to the mineral exploration. In this study, we test the distribution characteristics of geochemical elements data by using the histogram of element contents and the testing method of skewness and kurtosis. The distribution characteristics of Cu, Ag, Pb and Zn did not follow the normal distribution and lognormal distribution, showing the characteristics of high cluster fractal distribution. This research compares the geochemical anomalies of related elements extracted by adopting traditional statistical method, the 85% cumulative frequency method and the content-gross multifractal method. The results show that the content-gross multifractal method based on the spatial distribution and content distribution of elements is relatively reasonable for studying geochemistry anomalies. This method overcomes the limitations of traditional methods effectively and reflects the information of geochemical anomalies objectively in the study area.

    Stratigraphy
    Sedimentary Environment Characteristics of Upper Carboniferous Cameng Formation in Kongkong Chaka Area of Northern Qiangtang Basin,Tibet
    FENG Xing-lei,FU Xiu-gen,TAN Fu-wen,CHEN Wen-bin,
    2014, 28(5):  953-961. 
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    This paper focused on the study of the sedimentary environment about the source rock of Carboniferous Cameng Formation(C2c) in Qiangtang basin, which characteristics of petrology, sedimentary facies and geochemistry were analyzed. The results reveal the following aspects: the sedimentary environment of the source rock in Carboniferous Cameng Formation is the delta deposit; the hydrolysable and ferrum elements are high abundant, indicating an onshore to shallow sea environment with shallowwater depth; the values of paleoclimate indexes (C) are all greater than 0.8, showing a humid environment; the ratios of Sr/Ba are all less than 1 within range of 0.13 to 0.23, indicating a low-salinity and fresh terrestrial sedimentary environment; the relationship of V/Sc, V/(V+Ni), Th/U, Ni/Co, Fe2+/Fe3+ with V/Cr all manifest an oxygen-enriched water environment. The above conditions are all favorable to mass propagation of terrestrial organisms and aquatic organisms, and these organic matters are transported and deposit, providing the materials of the source rock in the study area.

    Establishment of the Stratotype Produced in the Mid-Late Quaternary in Hengshui Area,Hebei Province and Its Geological Implication
    LU Hai-feng,WANG Jin-yan,WANG Rui,
    2014, 28(5):  962-970. 
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    The paper made a descriptive record on the drill core ZK1 located at Jijiazhuang and the drill core ZK2 located at Zhaojiatun in the Hengshui suburbs by lithologic descriptions, lithofacies, age of stratigraphy, analysis of sporopollen and stratigraphic correlation. Combined with previous research results in the area, we drew conclusions that the two drilling cores revealed the Holocene with the thickness of 8-9 m in the study area, the Upper Pleistocene with the thickness of 31-36 m and the Middle Pleistocene with the thickness of 72-75 m. According to elevation of the wellheads and the bottom of the same petrofabric, the study area was speculated to locate on the ancient slope towards east direction. Mainly based on lithostratigraphy and chronostratigraphy, combined with sporopollen and the combination of main macro-characteristics and micro-markers, the drilling cores revealed the petrofabric of the equivalent thickness during the same stage in the study area; meanwhile, there was no significant differential uplifting-subsidence movement, and it was in a relatively stable sedimentation environment overall since the Middle Pleistocene.

    Contingency Table Analysis of Pebble Lithology and Roundness and Provenance Implications for the Upper Cretaceous of Yongfeng-Chongren Basin, Jiangxi
    TANG Chao, CHEN Liu-qin, GUO Fu-sheng, WANG Feng-zhi, XI Song, ZHAN
    2014, 28(5):  971-979. 
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    The Upper Cretaceous (including Hekou, Tangbian and Lianhe formations) conglomerates are widespread in Yongfeng-Chongren basin, Jiangxi Province, south China, which is the material basis of Danxia landforms. The contingency table analysis of pebble lithology and roundness is an effective approach to provenance interpretation. In this paper, it is the first time that the lithology and roundness of gravels from Yongfeng-Chongren basin are combined to make the contingency table. Gravels are mainly composed of quartzite, granitic rocks, sandstones and metamorphic rocks, and a small amount of mudstones and limestones. For the convenience of counting, the roundness of the gravels are subdivided into three levels including A+B (angular and sub-angular), C (sub-rounded) and D+E (rounded and well-rounded). Normally, when the value of A+B is fewer than expected and the value of D+E is more than expected, pebbles were considered to be transported for long distance. On the contrary, it shows short distance transport. The following conclusions are drawn: the pebbles of Hekou Formation came from more than one source, and they would came from the edge of the basin and Jilongshan, Xiangshan and Yuhuashan mountains and the northwestern Changlong area; the pebbles of Tangbian Formation were mainly derived from Jiandingfengshan and Yuhuashan mountains, and some parts from southeast Fengshan and Xindashan mountains; the Lianhe Formation’s pebbles were mainly derived from Jinhuashan and Zhangling mountains, and some might come from Jilonggang, Songshuling and Lingguling mountains in the northeastern part of the basin. The result of the provenance analysis could provide important basis for the formation and evolution of the Cretaceous red basins in south China.

    Study on Sediment Provenances in Jianghan Basin since Quaternary Based on Factorial Analysis
    YUAN Sheng-yuan, LI Chang-an
    2014, 28(5):  980-985. 
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    Taking drillinghole ZL located at the center of Jianghan Basin as an example, with method of ICP-MS,the R factor of trace element compositions of cores from the hole is analyzed to reveal sediment sources’ changes in Jianghan Basin since Quaternary in this paper. The results show that during 2.77 to 2.68 Ma B.P.,the deposition process is mainly near source according to trace element compositions of sediments in Jianghan Basin; during 2.68 to 2.23 Ma B.P.the clastic deposition in Jianghan Basin is obviously affected by felsic; during 2.23 to 1.25 Ma B.P. and since 1.25 Ma BP.the trace element of sediments is affected by Fe-Mg rocks, and it is indicated that the upper reaches of the Yangtze River which has a large-scale basic rocks distribution is the source provider of Jianghan Basin.

    Energy Geology
    Approach to Karst Reservoir Types and Classification of Ordovician Carbonate in Tahe Oilfield
    KANG Zhi-hong,RONG Yi-min,WEI Li-ling,LI Xue,CHEN Yi,CHEN Lin
    2014, 28(5):  986-994. 
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    The Ordovician reservoir of the Tahe oilfield is a complex fracture and vuggy karst carbonate reservoir which experienced multiphase karst and tectonic disruption. This is very difficult to identify the types of karst cave by conventional log data. The main reservoir space include karst cave, vug and cracks, which control distribution and accumulation of the reservoir fluid. It is very important for petroleum development that the different reservoir types are divided and distinguished. In this paper, based on six key wells of electric imaging logging (FMI), and the core sample characteristics, combined with the corresponding conventional logging data, the carbonate reservoir of the Tahe oilfield is divided into four categories:unfilled cave,collapsed cave, cave-filling of sand shale, solution fracture type. According to the conventional well logging response and result of four kinds of reservoir division, seven kinds of logging information GR, RD, RS, K3 (of the absolute value of lateral resistivity difference from bottom), AC, DEN and CNL are taken as inputs of neural network learning samples. By training neural network model of reservoir division, the neural networks model of reservoir type’s identification is established. Based on this network model, take TK604 well as an example to test the classification in the Tahe areas 6 and 7. Real data processing has proved that this method is effective. Through the actual data processing proved that the conventional log multiparameter constraint can be used to judge karst reservoir type, and initially semi-quantitative evaluation standard is formed, showing preliminarily that the method of the neural network method based on the imaging logging is suitable for complex carbonate reservoir in Tahe oilfield.

    Characteristics and Evolution of Ordovician Carbonate Platform Marginal Facies in Tazhong-Gucheng Area, Tarim Basin
    WANG Guan,FAN Tai-liang,LIU Hai-long
    2014, 28(5):  995-1007. 
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    The existence of Ordovician carbonate platform margin has already been proved in Tazhong-Gucheng area, Tarim Basin. However, the distribution, thickness and migration of it are ambiguous because of the great depth of strata, less drilling and limited seismic data quality. Based on analysis of the residual strata, combined with drilling and well logging data, seismic profiles and core samples, the development of Ordovician carbonate platform margin in research area can be chronologically divided into three stages: (1)Lower Ordovician Penglaiba Formation develops an obvious rimmed platform margin, nearly N-S trending, showing “S”-shape distribution; (2)Lower-Middle Ordovician Yingshan Formation generally has similar range of platform margin’s distribution to Penglaiba Formation, but shows reverse “S”-shape around GL1 well; Rimmed and ramped types both exist, and slightly retract inward; (3)Upper Ordovician Qiaerbake Formation-Lianglitage Formation develops two separate platform marginal facies belts in the north and south of Tazhong uplift; the northern one is ramped type; the southern one is rimmed type, with larger width and steeper slope. Generally, in Ordovician period, the platform marginal facies migrated from the overall N-S trending “S”-shape to the westward opening “V”shape. The carbonate platform margins migrated to center of the basin, and the platform edge-slope facies mainly showed a retrogradationalaggradational development in Early-Middle Ordovician. In Late Ordovician, the Tarim basin experienced a significant decline in sea level. Thus, the remnants of platform edge’s distribution underwent a significant narrowing. After the rapid regression, a new round of transgression began, resulting in that the platform marginal facies retreated towards the high part of the Tazhong platform.

    Sedimentary Characteristics and Their Evolution of Lianglitage Formation in Northwestern Tazhong Area
    ZUO Fan-fan,LIN Chang-song,GAO Da, ZHAO Jian-hua,XIA Shi-qiang,LI Hong
    2014, 28(5):  1008-1016. 
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    The Lianglitage Formation, being the high quality reservoir, has always been the important target in the researches for exploration in Tazhong area. However, researches on the sedimentary characteristics of the northwestern part in the northern slope of Tazhong area (Tazhong 85-49 well) still inadequate. Based on cores, thin-sections, well-logging data and seismic data, the Lianglitage Formation is divided into 3 third-order sequences, 5 systems tracts and 9 to 15 fourth-order sequences, and the high-resolution sequence stratigraphy framework is established in the research area. 8 microfacies are identified in research area and according to their specific combination, 4 sedimentary facies are recognized in fourth-order sequence, including reef complex, medium-high energy grain bank, medium-low-energy grain bank and lagoons-sea. Distributional characteristics of sedimentary facies is studied, based on the foundation of high-resolution sequence stratigraphy and sedimentary characteristics, focusing on the analysis of the facies evolution pattern in cross-section of HST and TST in SQ1 and SQ2 and contrast of facies distributions in flat between different periods. As a result, the evolution pattern of sedimentary facies is revealed, which benefits the further guidance of the oil and gas exploration of research area in the future.

    Study on the Influence of Strike-slip Fault Displacement on Reservoir in Northern Slope, Tazhong Area
    ZHANG Xin-chao,SUN Zan-dong,ZHAO Jun-sheng,PAN Yang-yong,WU Mei-zhen
    2014, 28(5):  1017-1022. 
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    Reservoir reformation and petroleum distributions in Ordovician carbonate reservoirs are affected by strike-slip faults with northeast direction in the Northern Slope of Tazhong area. Large scale strike-slip faults always show north-east strike direction. Unfortunately, the horizontal displacement is too shorter to be identified by using poor quality and low resolution seismic data. Strike-slip faults show ubiquitous pullapart areas along the strike direction, because they have been affected by the tensional stress with northwest direction. And pull-apart areas are developed along the direction of strike-slip faults mainly affected by the formation of local stresses. The width and height of these areas are easy to be identified in 3D seismic data. A method is then proposed for displacement calculation by using the width and height of the pull-apart area to replace the horizontal displacement and vertical displacement of fault. Displacement calculation results by this method show a high agreement to geology regularity of strike-slip faults development. Large displacement in strike-slip faults always means a high activity regional area, and also shows a profitability area for reservoir reformation or petroleum accumulation.

    A Discussion on Fault Conduit Mechanism and Control Factors of Petroleum Lateral Diversion
    JIANG Da-peng, DAI Yi-ding, LIU Li-hua, ZHANG Chao, LI Zhen-sheng
    2014, 28(5):  1023-1031. 
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    Fault is a complex internal structure geological body, that was an important migration pathway of petroleum. Oil and gas can migration along fracture in all directions, but vertical and lateral transportation is a primary way for hydrocarbon accumulation. At different stages of the fault activity cycle, fault conduit mechanism of transporting petroleum is different, and their characteristics are varied. Oil richness can be used to judge the strength of lateral diversion. By compared it with reservoir thickness, overlaying shale thickness and element of fault, it is concluded that overlaying shale thickness is a main factor to control lateral diversion, and reservoir thickness is the secondary factor. In conclusion, (1)Fault conduit has a characteristic of “faulting-cap rock” joint control feature. (2)Zhu 1 Sag has the characteristic of “two peaks” in hydrocarbons accumulating via carrier faults, and the peak of petroleum infilling is decided on regional caprock and fault conduit mechanism.

    Tectonic Activity Difference and Its Control on Hydrocarbon Accumulation of Volcanic Rock Reservoir in Eastern and Western Sags of Liaohe Depression
    ZHANG Jiang-tao,WU Zhi-ping,Lv Ming-zhen,YU Qian-qian
    2014, 28(5):  1032-1040. 
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    The geological settings of Eastern Sag and Western Sag in Liaohe Depression are similar, but the volcanic reservoirs in Eastern Sag are much more abundant than that in Western Sag. According to the present research, migration of the subsidence center and depocenter from West Sag to East Sag results in the diversities of tectonic evolution between Western Sag and Eastern Sag, and finally leads to different reservoir accumulation conditions which are the key factors influencing oil accumulation in volcanics of Western Sag and Eastern Sag. Firstly, the oil and gas transporting system in Eastern Sag is better than that in Western Sag. Fault activities were different in the two sags. The fault systems in the Western Sag were active only in the early stage, while the fault systems in the Eastern Sag were active until the end of the Paleogene. Thus, the fault activity period could not match the accumulation period in Western Sag. Secondly, since the late Es4 stage, tectonic activities in Eastern Sag have become more intense than in Western Sag, and a lot of intrusive trachyte have developed in Eastern Sag. This kind of lithology is easily reformed and then fissures generates, forming better reservoirs in Eastern Sag. Thirdly,different with Western Sag, in Eastern Sag volcanic rocks in Es3 stage are chiefly concordant intrusion along fault, distributed as dikes, sills and laccolites, contacting directly with the source rocks which are convenient for oil migration.

    Reasonable Utilization of Isothermal Adsorption Experiment Data to Predict the Shale Adsorbed Gas Content Changing with Burial Depth
    XING Jin-yan,JIANG Zhen-xue,CHEN Lei,HAO Jin
    2014, 28(5):  1041-1045. 
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    Adsorbed gas content under the condition of the reservoir temperature and pressure is of great significance for shale gas resource evaluation and target area selection. Therefore, it is necessary to obtain the shale adsorbed gas content and its transformation law under the double variable factors of the reservoir temperature and pressure. By reasonable utilization of isothermal adsorption experiment data under different temperatures, the temperature and pressure double variable factors turn into the single factor of burial depth. We choose one sample A do the isothermal adsorption experiment under different temperatures, rational utilization of different temperature points and experimental pressure, to finish the conversion between temperature, pressure and buried depth through the parameters of temperature gradient, pressure coefficient. Further predicting the corresponding adsorbed gas content of other temperature points, so as to build the adsorbed quantitative prediction model with the burial depth. We use the model to calculate the adsorbed gas content of untested temperature, and the result is relatively accurate. The model is seen as a new reliable method to calculate adsorbed gas content. The research shows that the adsorbed gas content increases first and then decreases with the burial depth increases, and there exists a depth turning point. Above the depth turning point, pressure has more important effect on adsorbed gas content than temperature, and below the depth turning point, temperature has more important influence than pressure. The method makes the best of the experimental data, reflecting the adsorbed gas content transformation law directly, and it has an important guiding significance for resource evaluation.

    Hydrology and Environment Geology
    Research on Heat Exchange Ability of Ground-Source Heat Pump by Field Test of Beijing Plain
    LUAN Ying-bo,WEI Wan-shun,YU Yuan,YANG Jun-wei
    2014, 28(5):  1046-1052. 
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    Rock and soil mass not only influences the distribution features of ground temperature field, but also is the key factor of evaluation of shallow geothermal energy resources and engineering design. To obtain the thermal properties and heat transfer performance of local rock and soil is the lynchpin to guarantee the efficient and stable operation of the heat pump. According to the field test results of heat exchange performance of ground-source heat pump projects under construction in Beijing, we study the effects of integrated thermal conductivity by stratum structure, lithology, hydro-geological conditions and backfill material. The results showed that it’s beneficial to improve the heat transfer performance of the system by means of selecting appropriate backfill materials under the same conditions. The heat exchange performance of bentonite and cement as backfill material is improved by 17.6% and 19.7% respectively compared with fine sand. It can be concluded that the rock-soil mass and groundwater are the substance bases of accumulation and spread of thermal energy. The groundwater and strata texture determine the distribution pattern of geotemperature field and heat transfer efficiency. There is a direct relationship between heat transfer efficiency of ground heat exchanger with soil particles, groundwater table and groundwater seepage. The larger soil particles become, the less groundwater depth gets. The seepage velocity has obvious invigoration effect on the heat transfer efficiency of ground heat exchanger.

    Characteristics and Formation of the Songshan Hot Spring in Yanqing County of Beijing
    LONG Mi,ZHOU Xun,LI Ting,WANG Xiao-cui,TANG Li-wei,CHEN Ting,GUO Shuai
    2014, 28(5):  1053-1060. 
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    The Songshan hot spring is located in the Songshan Forest Park in Yanqing County of Beijing. Granite occurs near the hot spring and fissures are developed in the rock. There are two wells flowing hot water closing to the hot spring. Temperatures of the hot spring and the flowing wells range from 32 ℃ to 42 ℃. The major cations of the hot water are Na+, K+ and Ca2+,and the major anions of the hot water are SO42-, HCO-3 and Cl-. The hot water is of SO4-Na type. The hot water has TDS of 0.548-0.566 g/L, pH of 9.14-9.21, H2SiO3 of 87.1-97.1 mg/L and F- of 19.0-20.8 mg/L. Isotopic data of hydrogen and oxygen indicate that the hot water in the study area is of meteoric origin. The recharge altitude of the hot spring is estimated as 1,256-1,351 m, the temperature of the recharge area, 4.4-8.8 ℃, the age of the hot water, 14.19-48.95 a, the temperature of the geothermal reservoir, 114-119 ℃, and the circulation depth of the hot water, 2,236-2,274 m. The Songshan hot spring emerges on the mountain slope after the groundwater in the granite receives recharge from precipitation in the mountain area and undergoes deep circulation and obtains heat flow from beneath.

    The Residual Gas Saturation of Different Components of Saline Flooding CO2
    WU Ai-bing,LI Yi,CHANG Chun,YU Qing-chun
    2014, 28(5):  1061-1067. 
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    In many mechanisms of the geological storage of CO2 in deep saline aquifers, the trapped gas storage has great potential, which accounts for about 30% of the total storage. Residual gas saturation is a very important parameter to evaluate storage capacity of trapped gas.This thesis can qualitatively evaluate storage capacity of trapped gas in different saline aquifers and provide basic parameters for assessing of storage capacity in deep saline aquifers by measuring residual CO2 saturation of different components of saline flooding CO2. At the same time, it can give some guidances and references in choosing the project site and the target aquifer of the geological storage ofCO2in deep saline aquifers. We used distilled water,NaCl solution, CaCl2 solution and the mixture of NaCl and CaCl2 solution (the mass ratio is 1∶1), which were all saturated by CO2 and the mass concentration of all solutions is 10%, to inject into CO2 saturated core and finally we calculated residual CO2 saturation. The injection process can be divided into two phases:piston drainage, portable drainage. Experimental results show that the ascending order of residual CO2 saturation of four kinds of liquid flooding is distilled water, the mixture solution, NaCl solution and CaCl2 solution. The results indicate that interfacial tension plays a dominant role in the injection process under the influence of interfacial tension and fluid viscosity. Among the three types of saline, storage potential of trapped gas of Cl-Ca-type water is maximum, followed by Cl-Na-type water. The potential of Cl-Na·Ca-type water is minimum.

    Engineering Geology and Environmental Geology
    Ancient Landslide Identification and Characteristics Using Remote Sensing along Eastern Edge of the Heqing Basin
    GUO Zhao-cheng,NIE Hong-feng,YANG Liang,TU Jie-nan,HE Peng,TONG Li-qiang
    2014, 28(5):  1068-1076. 
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    Large ancient landslides offer clues to the regional tectonics, climate change and paleoenvironment evolution that would be able to influence the development of human society in the future. It is difficult to identify ancient landslides, but with the development of remote sensing technology, it can be used to effectively recognize ancient landslides. Based on the image texture, tone characteristics, two ancient landslides have been identified by using the digital landslide technical method along the eastern margin of the Heqing Basin. The information of these ancient landslides- features, such as the location, extent and elevation was extracted. The calculation results show that the two ancient landslides- scales reached 130 million and 564 million m3, respectively. The lithology, geological structure, stratigraphy covering relation and ancient seismic activity of the study area were analyzed in detail, suggesting that the two ancient landslides were triggered by powerful earthquakes. By comparative analyzing the relative position of the two ancient landslides with the Dali-Lijiang railway and the Heqing railway station, it was concluded that the construction of large linear projects should not only focus on the current regional stability evaluation, but also consider the ancient seismic activity, especially avoiding steep fault along basin edges.

    Research on Development Characteristics and Size of Landslides in the Three Gorges Area
    PENG Ling,XU Su-ning,PENG Jun-huan
    2014, 28(5):  1077-1086. 
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    The research on development characteristics and size of landslides has a great significance to landslide risk assessment and geomorphic evolution analysis. In this paper, the Three Gorges area was selected as a study area, and landslides’development characteristics and parameters such as area, volume, thickness and size density were analyzed using GIS technology and statistical method, and the variable dimension fractal theory was used to study fractal characteristics of landslide size and geological environmental factors. The results show that the regional landslide has the spatial pattern and cluster feature for soil- and rock-type landslides, and different types of landslides have characteristics of agglomeration in the distribution and no uniformity in the size. The relations of frequency to size and frequency to velocity of landslides exhibit the power law, indicating that landslide system has the property of self-organized criticality. Furthermore,the results indicate that landslide size has the variable dimension fractal characteristics, revealing the sensitivity relationship between landslide size and geological environmental factors. The results are important to improve understanding of the development law and risk assessment of landslides.

    Comprehensive Monitoring of Failure Process and Danger Forecast of the Wangxia Unstable Rock Mass in the Three Gorges Reservoir
    LE Qi-lang,CAI Ling-ling,WANG Hong-de,GAO You-long
    2014, 28(5):  1087-1095. 
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    Two serious deformations occurred in the Wangxia unstable rock mass in Wushan County in the Three Gorges Reservoir in 2010 and 2011,but after geological surveying, monitoring-scheme designing, monitoring-data processing and macroscopic phenomena analyzing, these collapse deformations were successfully forecasted through long-term monitoring rock masses by total station, crack displacement meter, GPS, etc.,avoiding heavy casualties. The deformations of the unstable rock mass contain two types of gradual change and mutation.It should adopt corresponding monitoring methods and frequencies in different deformation stages based on geological survey, and the key parts of the unstable rock masss hould be monitored. The monitoring data should be analyzed with close combination of the macro phenomena, and the deformation trend should be grasped from the rear, precipice and cliff bottom of the rock mass. The monitoring scheme of unstable rock masses should observe the five principles, which are detail investigation, careful deployment, phenomenon observation, grasping trend and accurate prediction, ie. Wangxia Experience. This experience can provide the reference for monitoring unstable rock masses.

    Geological Environment Vulnerability Evaluation of the Economic Zone in South Shandong
    LI Yuan-zhong,ZHAO Shu-quan,WU Xiong
    2014, 28(5):  1096-1102. 
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    The mineral and groundwater resources are very rich in the economic region of south Shandong. The geological environment problems caused by continuously pumping large quantity of groundwater include mine-dout area breakdown, karst collapse, land subsidence, cone of depression and saltwater intrusion. With 17 eva-luation factors, such as landform, rock-soil body characteristics, hydrogeological condition, environmental engineering geology problems, geological resource and ergonomic activity, etc., this paper used Fuller triangle to define the factor weight and evaluate the geological environment vulnerability with experts clustering procedure. Four evaluation factors, i.e. soil environmental quality (T), engineering geology environment (G), geological hazard dangerous assessment (Z) and geological environment load capacity (C) were utilized to evaluate the suitability of the key cities in the study area with map overlapping method. The result shows that the whole region can be divided into four grade vulnerability sections, which are the serious vulnerability section, the high vulnerability section, the medium vulnerability section and the low vulnerability section; Heze city and Linyi city are located at the high vulnerability section; Jining city, Zaozhuang city and Rizhao city are located at the medium vulnerability section. The comprehensive assessment of the geological environment of the study area indicates that the five key cities all have basic suitable environment, and the west district of Zaozhuang city has suitable environment.