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    29 December 2009, Volume 23 Issue 6
    Engineering Geology and Environmental Geology
    Vast Paleo-Lakes, Planation Surface and Topographic Evolution of the Tibetan Plateau
    WU Zhen-Han,WU Zhong-Hai,HU Dao-Gong,ZHOU Chun-Jing,YE Pei-Sheng, Zhang Yao-Ling
    2009, 23(6):  993-1002. 
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    The Tibetan Plateau isostatically uplifted after contractional shortening and crustal thickening in Paleogene and is dominated by strikeslip and extension in Late Cenozoic. Very vast lakes formed in Early Miocene and Late Pleistocene in central Tibetan Plateau respectively, and large paleolakes formed in Pliocene and Early Pleistocene alternatively in northern and eastern Tibetan Plateau. Level of vast lakes had been base surface for incision in Early Miocene from (~24.1±0.6)Ma to (~14.5±05)Ma, and lakes and top lacustrine deposits of Wudaoliang Group became base surface for erosion and peneplanation since Late Miocene, which formed planation surface or peneplain of the Tibetan Plateau. Upstream incision of rivers led to westward motion of boundary between internally and externally drained regions and disappearance of paleo-lakes in Quaternary, and Quaternary incision of external rivers gradually formed present topography characterized by deep valleys, high mountains and remained peneplain in eastern Tibetan Plateau.

    A Seismic Study on the Detachment Layer in Middle Crust and Its Relation to Subdivision of Active Tectonics in North China
    LI Tao, Zhou Shi-Qing
    2009, 23(6):  1003-1011. 
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    In North China the upper crust is dominated by brittle deformation and lower crust is characterized by ductile extension. However these two styles of different deformation have the same extensional direction and the similar extension amount, which resulted in the development of a regional detachment layer along the top of the middle crust in North China due to differential movement between the upper and lower crust. The detachment structure has controlled the development of the basin-range pattern and the basement of North China Block. The tectonics in this region is produced by thin-skinned extension in the brittle upper crust.The stair-shape detachment layer in North China Block is distributed continuously at depth 12-22 km (mostly at 15-18 km). Eleven detached units (or regions) can be identified. Brittle faulting mainly occurs in the upper crust. The locations of the faulted blocks, configuration and their deformation manners are dictated jointly by occurrence of the ramp-flat detachment, cutoff lines perpendicular to the detachment and accommodation faults parallel to the detachment. Three primary axes of the rifted-depression, two main cutoff lines and three main accommodating faults have been recognized.

    Environmental Evolution at the Drilling Hole K3 in the East-south Margin of Ebinur Lake, Xinjiang in Late Cenozoic
    ZHANG Jin-Qi, Liu-Bin, Chen Xu-Guang, Sun Xiao-Ming, Wang Yun-Sheng
    2009, 23(6):  1012-1021. 
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    The 500.8 meters depth drilling hole K3 with a core recovery efficiency of 80.4% is located at the eastsouth margin of Ebinur Lake in Zhunger Basin, Xinjiang. Based on the study of OSL dating, palaeomagnetism, susceptibility, micropaleontology (ostracoda and foraminifera), palynology and lithostratigraphy in the borehole, it is determined that the drilled sequences belong to the deposits since cir. 4.2 Ma,there was a lake environment during 3.6-4.2 Ma ,and since cir. 3.6 Ma the sedimentary environment changed from hemi-deep or shallow lake to littoral lake or subaqueous delta accompanying with the Hami Movement as a result of the quickly uplifting of Qinghai-Tibet Plateau, the aridification situation was also aggravating in the study area; during Late Pliocene (cir. 2.6-3.0  Ma) there was a basin margin and fluvial fan sedimentary system; at cir. 2.6 Ma under the influence of the Xiyu Movement and Yanshuigou Movement, the meandering stream  system was developed in the study area. Since the Middle Pleistocene Revolution i.e.cir. 0.8 Ma, the aridification situation was similar to that of modern times. The uncontinuous spore-pollen diagram and ostracoda distribution show a complicated development of sedimentary dynamics and water bodies since 4.2 Ma. The environmental change in the study area had been controlled by the tecto-climatic cycles.

    OSL Age of Fault Collapse Wedge in Xinding Basin, Shanxi Province and Its Significance for Paleoearthquake Events
    ZHAO Jun-Xiang, REN Jun-Jie, Yu Shen-E, Zhang Shi-Min, Ding Rui
    2009, 23(6):  1022-1029. 
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    The fault scrap collapse wedge is the direct result of fault activity, it is also signification of paleoearthquake events, its accurate dating is the key to solve the problems about paleoearthquake events.Luminescence techniques are rapidly progressing in recent years.Simplified multiple aliquot regenerative-dose (SMAR) protocol is already applied successfully in loessial sediments after 130 ka.The studied samples are collected detailedly in two fault scarp collapse wedges(D1 and D2) from the schematic section of Nanyukou in north piedmont zone of Wutai Mountain in Xinding basin, Shanxi Province.The sample ages are acquired with fine grain quartz (4-11 μm) SMAR protocol.The results of the OSL dating show that evolutional models of D1 and D2 are different from general model of normal fault collapse wedge.The palaeotopography of D1 is formed by accumulating nearby the fault to stretch out far, whereas the palaeotopography of D2 is formed by accumulating horizontally and is thicker than D1.After dilapidation powerful current has rised in D1. The results indicate that the older paleoearthquake event occurred between (42.77±2.46) ka and (61.72±2.82) ka, the younger paleoearthquake event occurred between (3280±287) ka and (47.92±0.94) ka.The interval of the two paleoearthquake events is between 10 ka and 15 ka.

    Geochemistry of the Chayong Ophiolite in North Qiangtang Basin,Qinghai-Tibet Plateau: Implications for Tectonics
    LI Shan-Ping, Chen You-Shun, Li Wu-Fu, Wang Qin-Yuan, Qi Sheng-Sheng
    2009, 23(6):  1030-1038. 
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    The Chayong ophiolite is a part of the northern extension of Ganze-Litang suture zone in Zhiduo area of the North Qiangtang basin in Qinghai-Tibet Plateau,it consists of basic cumulates,diabase dyke swarms,basic lavas and sedimentaryorigin cherts,but mantle peridotites are absent.Due to the effect of structures after the ophiolite formed,they are strongly metamorphized and deformed, and mostly dismembered to tectonic blocks and slabs. The cumulates comprise altered olivine pyroxenite and gabbro. The former is characterized by low SiO2,TiO2,P2O5 and high MgO contents,significant enrichment of Rb,Th,Cr and depletion of Sr,Nb,Y . In contrast, the latter is characterized by low SiO2 and K2O contents,high MgO,TiO2 and Al2O3 contents. The diabase dykes are geochemically characterized by significant enrichment of Rb,Ba,Th and slight depletion of Y and Yb coupled with similar trace element spidergrams to midocean ridge basalts. The basalts exhibit high TiO2 and low K2O contents, typical feature of a low potassium tholeiite series. Additionally, they display fractionation of LREE from HREE fractionation, i.e,enrichment of LREE no significant Eu anomalies and near flat REE curves,resembling oceanic basalts. In combination with geochemical characteristics, regional geology and tectonic environment, we propose that the Chayong ophiolite was possibly produced in an ocean basin setting.

    Yingmailai Granitic Intrusion in the Southern Tianshan: Magnetite-series or Ilmenite-series?
    MA Le-Tian,ZHANG Zhao-Chong,DONG Shu-Yun,ZHANG Shu,ZHANG Dong-Yang, HUANG He
    2009, 23(6):  1039-1048. 
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     The Yingmailai granitic intrusion is located in the middle part of the southern Tianshan. It consists predominantly of biotite K-feldspar granite with minor two-mica K-feldspar granite. They have similar whole-rock geochemical characteristics, but distinct mineralogy. Opaque minerals in biotite K-feldspar granite are ilmenite, whereas they are magnetite in two-mica K-feldspar granite. According to Ishihara's classification(1977), biotite K-feldspar granite can undoubtedly be classified to ilmenite-series. Although some characteristics, e.g, presence of magnetite and Mg-rich biotite, suggest magnetiteseries, it should be noted that the magnetite in two-mica-K-feldspar granite is formed by post magmatism. In combination with low Fe3+ /(Fe3++Fe2+)ratio and presence of indicating mineral—muscovite, it can be inferred that it also belongs to ilmeniteseries. In addition,the mineralogical and geochemical characteristics of the Yingmailai granitic intrusion indicate Stype granitoids,which suggests that ilmeniteseries correspond to Stype granite in the southern Tianshan. This research also suggests that the southern Tianshan had not experienced within plate during Early Permian.

    The Rock- and Ore-forming Ages of the Laochang Porphyry Molybdenum Deposit in Lancang, Yunnan
    LI Feng,Lu Wen-Ju, Yang Ying-Zhong, Chen Hui, Luo Si-Liang, SHI Zeng-Long
    2009, 23(6):  1049-1055. 
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    The Laochang region in western Yunnan is one of the areas with significant breakthrough for new discovery of great thick porphyry molybdenum ore bodies in the deep since 2008. On the basis of the  analysis to mineralizing system texture, the rock- and ore-forming ages of the granite-porphyry and related molybdenum ores were precisely redefined by the SHRIMP zircon U-Pb and molybdenite Re-Os dating method. The results show that the age of ore-forming graniteporphyry is (44.6±1.1)Ma, and the Re-Os isochron of molybdenites is (43.78±0.78)Ma. It is suggested that a largescale Mo(Cu)-mineralization exists in this region, which related to Himalayan concealed granite-porphyry,and consistent with the peak period of Cenozoic magmatism-mineralization in forming ages, and formed in intracontinental collision orogenic setting.

    Thermoelectric Coefficient, Conductive Type and Significance of the Pyrite from Yixingzhai Gold Deposit in Fanshi County, Shanxi Province, China
    LI Cheng-Lu, Li-Qing-Rong, Luo-Jun-Yan, Song-Ji-Xie, Zhang-Ju-Quan
    2009, 23(6):  1056-1063. 
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    The gold deposit in Yixingzhai area, Fanshi County of Shanxi Province, is a large scaled quartz vein type deposit. In order to obtain more information about the zoning of the gold veins, totally 4,158 pyrite grains from 35 ore samples were analysed using a BHTE-6 type of thermoelectric instrument. The result reveals that the thermoelectric conductive type of the pyrite is mainly of N type, and the percent of the N type pyrite grains (N%) amounts to 75.1% of the total, with a mean thermoelectric coefficient of the N type pyrite (αN) being-155.3 μV/℃. The assembledge of the thermoelectric conductive types of the pyrite changes successively from N%﹥P% of the early goldpoor pyrite-sericite-silicification stage to N%﹤P% of the later silicatecarbonatification stage. Spatially, the absolute mean value of αN(|αN|) and N% increase downward from the 1,190 m level to the 830 m level with decreasing of the value of αP and P%, indicating a normal vertical zoning sequence. A low-medium temperature of 143.3-323.3 ℃ is derived by calculation of pyrite thermoelectric coefficient. The thermoelectric coefficient of the pyrite in the rich ore segment is confined within the range of 0--200 μV/℃. A calculation with empirical formula implies that the lower to middle parts of the orebody have been exhumed until now, whereas the buried ore is spatially quite stable. Furthermore, the authors suggest that good exploring prospect would be expectable below 830 m level.

    In-situ Test and Study on the Hemimorphite and It's Thermal Phase Transformation by Technology of High Temperature Raman Spectra
    ZHANG Jian, Yu Xue-Hui, Xie Jun, You Jing-Lin, Mo Xuan-Xue
    2009, 23(6):  1064-1069. 
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    An in-situ Raman spectra test and study on the hemimorphite were carried out by high temperature Raman spectra technique. The test results show that the characteristic Raman peak of  3,470 cm-1  representing O-H stretching vibration in the molecular H2O is disappeared as the hemimorphite being heated  800 K, but the characteristic peak 926 cm-1 marked Q1 of the main framework [Si2O7] is been retained, which means the structure of the hemimorphite is not changed as the H2O lost. The characteristic peak of 3,580 cm-1 related to stretching vibration of the O-H in the structure water (OH) is disappeared as the sample being heated 1,050 K.The relative intensity of the characteristic peak 926 cm-1 related to symmetric stretching vibration of nonbridging oxygen of structure unit Q1 gradually decreases, comparing with the growing Raman band of Q0 characteristic peak at 852.4 cm-1,which indicates the phase transformation of the hemimorphite is started out at 1,050 K. The structure water (OH) is dehydrated completely as the temperature is over 1,100 K, the characteristic peak (3,580 cm-1) of the structure water (OH) disappears completely, the characteristic peak related to Si-Onb stretching vibration becomes 855 cm-1, which shows that primary Q1 of the hemimorphite is returned to Q0 (i.e  [SiO4] ), and which means that the hemimorphite is completely transformed to willemite.

    Petroleum geology
    Favorable Structural Traps Forecasting of Longmen Mountains Thrust Belt in Western Sichuan Basin
    JIN Wen-Zheng, TANG Liang-Jie,WAN Gui-Mei, WANG Jun-Peng
    2009, 23(6):  1070-1076. 
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     Field investigation and explained seismic profiles show that Longmen Mountains thrust belt has very complex structural characters, such as popup, triangle belt, fault related fold and duplex.These structures can form various kinds of hydrocarbon pools and have some regular patterns in their distributions: one is zonation, this means that the distribution of pools made of various kinds of structures are close related to the main faults on Longmen Mountains thrust belt, for example, there should be some faults related to fold type pools between the Beichuan-Yingxiu fault and the Majiaoba- Tongjichang-Shuangshi fault and some triangle belt type pools between the Majiaoba-Tongjichang-Shuangshi fault and the GuangyuanGuankou-Dayi fault, etc.; the other is stratification, which means the detachment layers developed in Longmen Mountains thrust belt have very great influence on the pools’ distribution in profiles, for example, the region on the detachment layers has more types of structural pools than that beneath the detachment layers.

    Characteristics of Cenozoic Fault System and Its Significance in Petroleum Geology in Kongnan Area,Huanghua Depression
    NENG Yuan, Qi Jia-Fu ,LI Ting-Hui , ZHANG Ge, Li MIng-Gang, SHI Kui-Tai
    2009, 23(6):  1077-1084. 
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    Kongnan area of Huanghua depression has experienced rift stage, faultedsag stage and sag stage with complex fault systems. Based on the activity, the fault systems can be divided into two types: The Cangdong extension fault system and Xuxi rightlateral strike-slip fault system. Cangdong fault is a listric normal fault slipping into the deep crust and controlling the global deformation of Kongnan area. The Xuxi fault can be considered as a secondary fault in the hanging wall of Cangdong fault. In the stage of Kongdian Formation depositing, the two faults performed as normal faults, cocontrolling the distribution of Kongdian Formation. When the 3rd Member of Shahejie Formation was depositing,  Xuxi fault system performed as a right-lateral strike-slip fault which was influenced by the pre-existed basement fault. With the control of the process of extension and strike-slip,abundant hydrocarbon had accumulated in the centralnorth part  of Kongnan area.

    Decollement Structure and Stratified Deformation of Tazhong Lower Uplift,Tarim Basin
    HE Chun-Bo, TANG Liang-Jie, HUANG Tai-Zhu, LI Hui-Li, NING Fei
    2009, 23(6):  1085-1092. 
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    Tazhong lower uplift forming during Paleozoic was a favorable area for hydrocarbon migration and accumulation, so it's very important to study the structural distortion character for petroleum exploration. Based on seismic and well data, seismic interpretation and restoration of balanced crosssections were carried out, and the results indicate: (1) Besides basement involvement structures in the part segment of No. 1 fault, the faults were dominated by detachment faults which formed in Middle-Lower Cambrian salt layers. (2) The deformation styles were different in the upon and underneath salt layers, and the distortion was stronger in the upon salt layer than that in the underneath salt layer. (3) The stratified deformation was coordinated by salt layers. (4) The stratified deformation was controlled by both subduction orogeny and decollement of salt layers.

    The Thermal History of the Qinshui Basin in Shanxi Province
    CHENG Jin, HONG Xin-Wen, WANG Xiao-Niu
    2009, 23(6):  1093-1099. 
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    The Qinshui Basin within the North China Craton is a potential area for natural gas exploration,and thus the thermal history is a key to evaluate the reservation of the natural gas in this basin.Using apatite fission track and vitrinite reflection modelling techniques,the thermal history of the Qinshui Basin in Shanxi Province was modelled.The temperature gradients of the Qinshui Basin changed with geological stages:3 ℃/100 m at Early Palaeozoic,2.5-3.0 ℃/100 m from Late Permian through Triassic,3.0-4.0 ℃/100 m at Early-Middle Jurassic,4.5-6.5 ℃/100 m at Late JurassicEarly Cretaceous,5.5-6.5 ℃/100 m at Late Cretaceous to Palaeogene,6.0 ℃/100 m at Late Palaeogene and 4.2 ℃/100 m at Early Neogene.Since Miocene to the present,the temperature gradient kept relatively stable at 3 ℃/100 m.

    Analysis on Controlling Factors and Characteristic of Xu-6 Sandstone Reservoir (Upper Triassic) in Guang'an Region, Central Sichuan Basin
    JI Li-Dan, JIA Ai-Lin, HE Dong-Bo, WEI Yun-Sheng, SHAO Hui
    2009, 23(6):  1100-1106. 
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     The Xu-6 reservoir of Guang'an gas field is a large scale sandstone complex of distributary channels of braided delta plain sub facies, and the sandstones of reservoir are mainly medium grained feldspar detritus sandstone and detritus sandstone. It has low porosity and ultra low permeability, with a porosity distribution range of 3% to 15% and permeability distribution range of 0. 01×10-3~1×10-3 μm2. Main and sub-main distributary channels are effective reservoirs, and the alternate distribution of permeable zones and compact layers in sand complex lead to complicated reservoir distribution. Based on above results, and combined with diagenesis, the controlling factors of reservoirs are discussed. The reservoir development is controlled by three sedimentary factors of different scales: distinctive rock composition of sandstones from different source regions which affects enrichment areas of reservoirs; sedimentary evolution which controls reservoir distribution sections; sedimentary micro facies which determines the heterogeneity in sandstones of favorable sections. Strong compaction of sandstones in acid environment of coal measures layer is the main cause of general low permeability. Medium and coarse grained feldspar detritus sandstones deposited in main distributary channels, which have relatively high secondary dissolved pores, are the main sandstone type of reservoirs.

    The Application of Seismic Sedimentology and Reservoir Prediction of Karratha Formation in the Tahe Oilfield
    LI Bin, YANG Ying-Chun, HE Yu-Ping, ZHANG Bai-Tao
    2009, 23(6):  1107-1112. 
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     According to the characteristics of sand impedance close with shale's in Karratha reservoir containing carboniferous seriously,the article put forward facies-controlled reservoir prediction using seismic sedimentary. The article described key technology methods of the seismic sedimentary, such as the smallest isochronia-unit built by time-frequency analysis, rock and lithofacies physics phase analysis to determine the seismic response under the smallest isochronia-unit. Research results suggested that the thick sandstone with strong oscillation amplitude reflection. The plane quantitative analysis of pseudo-seismic entropy and twisting properties of the distinction between the effective distribution of sand and shale, may provide information for portraying the distribution of sand and shale accurately and for choosing favorable zones. Sand shape is described by attribute projection technology using inversion data. The research carried out the practical significance of the concept of facies-controlled reservoir prediction,demonstrated good discipline advantages of the seismic sedimentology in the sedimentary micro-facies analysis and forecasting lithologic traps.

    The Sedimentary Characteristics, Evolution and Controlling Factors of Southern Margin, Yangtze Carbonate Platform During the Hercynian-Indosinian Stage
    SHI Guo, TIAN Jing-Chun, ZHANG Xiang, LI Rong, YU Mei-Yi
    2009, 23(6):  1113-1120. 
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    The carbonate platform developed on the Yangtze block during the Hercynian-Indosinian stage. Platform margin depositional system developed in the southern carbonate platform including four sedimentary types: the beach of carbonate platform margin, the reef platform of carbonate platform margin, platform margin slope and the sea between beach (reef). According to development characteristics of platform margin, four stages can be divided: the platform margin strip distributed along the line of Mile-Shizong-Qinglong-Nandan-Hechi during the Middle Devonian-Late Devonian(SS1), the reefbank of platform margin developed widely; the platform margin strip distributed along the line of Qinglong-Liupanshui-Anshun during the Early Carboniferous-early Early Permian(SS2-SS3), platform margin beach developed widely; the platform margin strip distributed along the line of Zhenfeng-Ziyun-Luodian-Hechi-Liuzhou during the the late Early Permian-Late Permian(SS4), the reef-bank of platform margin developed widely; the platform margin strip distributed along the line of Zhenfeng-Guiyang-Fuquan during Early Triassic-Middle Triassic(SS5), platform margin oolitic beach developed in the the Early Triassic, platform margin dominated reef developed in the Late Triassic. The study proved that horizontal migration of platform margin was mainly controlled by syndepositional faults, the vertical sequence evolution of platform margin was mainly controlled by sealevel change, the type of margin reef-bank was controlled by different types of carbonate secret organisms.

    The Inverted River and Its Origin in Palaeo-karst Drainage Basin of Ordovician in Block 4, Tahe Oilfield
    LIU Yong-Li, CA Zhong-Xian
    2009, 23(6):  1121-1125. 
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    Because of structure movement, lithology diversity, morphologic prominence, etc, river system capture usually appears in modern karst drainage basin, accompanied by a series of peculiar hydrogeomorphic phenomenon like divide move- damage, capturing elbow, wind gap, beheaded river and inverted river, etc. Based on 3D seismic data, by applying flattening, accurate coherence analysis and seismic imaging, the karst palaeogeomorphology and palaeodrainage pattern are described and recognized, where the peculiar hydrogeomorphic phenomenon is discovered. In the light of the theory on modern river system capture, it had been south- confluence structure in the east of Block 4, Tahe Oilfield. Then, the base level of erosion had declined in the northwest, and the north border of south-confluence drainage basin was captured by underground way, so the inverted river was builtup. The evolutionary process of karst palaeodrainage pattern and drainage basin were reappeared, supplying a signi
    ficant foundation for revealing Ordovician palaeo-karst built-up regular pattern for Tahe Oilfield.

    Method of Prediction and Application on Stochastical Simulating 3D Parameter Field of Rock Mechanics
    CAO Zheng-Lin, ZHENG Hong-Jun, GOU Ying-Chun, YUAN Jian-Ying, ZHAO Ying-Cheng
    2009, 23(6):  1126-1130. 
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     Presently, the methods of conventional log data are widely used to calculate rock mechanics parameters and are strongly required by fissure working rebuilding of artificial fracturing with the purpose of increasing oil production rate in oil fields. The method of prediction on stochastical simulating 3D parameter field of rock mechanics is brought forward in this paper. Namely, rock mechanics parameters- curve obtained by known and limited conventional log materials is took as inputs of hard data;and seismic attribute data body, hydrating of mud shale and rock environmental parameters data is took as constraint of soft data. By simulating stochastically through optimizing algorithm of Sequential Gauss Simulation,dynamical data field of rock mechanics parameter of three-dimensional space are gotten, then log response of rock mechanics parameters in position of any point in space is predicted. The special format of  the log responses to refect the dynamic change rule is presented for use of producing and engineering according to demand of exploration and development. Sequentially, the method provides a significant guiding role to establish perfect drilling, well completion, oil gas development project and technical measures in exploration and development.

    Engineering Geology and Environmental Geology
    Controlling Factors of Gas Hydrate Occurrences in the X Block of Shenhu Area,South China Sea
    GONG Jian-Meng, HU Hua-Beng, WANG Wen-Juan, LI Gang, YANG Yan-Qiu, MA Li-Jie
    2009, 23(6):  1131-1137. 
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     In order to understand the main controlling factors of gas hydrate occurrences in the X Block of Shenhu area, South China Sea, the fine seismic explanations and seismic facies studies of gas hydrate were carried out. The results show that there exist three important faults and lots of collapse structures, multilayer hydratebearing sediments exist in the gas hydrate stable zone, which have big thickness and good continuity in the base of the gas hydrate stable zone. In combination with seismic reflection features and probable gas resource discussion, it is concluded that there probably exist two kinds of reservoir models in the X Block. In the areas where faults or collapse structures develop, the gas resource is probably composed of thermogenic gas, gas hydrate is characterized by multilayer distribution, while in the inactive areas the gas resource is probably composed of biogenic gas, and gas hydrate is characterized by monolayer, which mainly distributes in a narrow zone on the surface of BSR(bottomsimulating seismic reflector).

    Fractal Research on Seamount Topography in the West Pacific Ocean
    ZHANG Wei-Yan, ZHANG Fu-Yuan, SHU Ke-Chao, YANG Ke-Gong, HU Guang-Dao, CHENG Yong-Shou, LI Shou-Jun, DIAO Hong-Qiao
    2009, 23(6):  1138-1146. 
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    On the basis of fractal research on the pointy seamount and guyot topography of Magellan seamounts, WakeMarcus seamounts, Marshall Islands, MidPacific Mountains and Lines Islands in the west Pacific Ocean, it is indicated that the different terrains of volcano shape type should display the different fractal characteristics. The fractal research on terrain shape  shows that the guyot has the single fractal structure and the seamount has the multifractal structure. The multifractal of the seamount mainly shows the great tectonic fractal and the small texture fractal,and the application of fractal dimension is demonstrated for quantitative characterization of the Pacific seamount topography roughness. The contour fractal shows that there are obvious several subsections of contour fractal which basically retains stable, possibly because the different geological processes on the different depths of the seamount have developed. It is possibly used to carry on vertical zoning of the geomorphic process. The fractal dimension of guyot is smaller than that of pointy seamount in the same seamounts.

    Analysis on Internal Sealing Technologies of Hydrate Pressure-Temperature Core Samplers
    ZHANG Ling, JIANG Guo-Sheng, NING Fu-Long,TU Yun-Zhong,WU Xiang, DOU Bin
    2009, 23(6):  1147-1152. 
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    While drilling in the gas hydrate bearing formation under the seabed, it is very important to use the pressure core sampler(PCS) tool to obtain pressure cores for the further core handling and analyzing. The current domestic state of the art with respect to pressure-temperature core samplers is firstly reviewed in this article. Internal sealing technologies of PCS are analyzed from the upper and lower seals of the sample chamber, which include some seals, such as the ball valve and O-rings. The sealing characteristics of two domestic samplers are analyzed. Based on the above analysis, with the features of core in-situ handling and analyzing, the sealing technologies of PCS and two domestic samplers have been discussed. At last, some suggestions are brought out for designing the seals of sampler, maintaining the in-situ pressure and temperature, and transferring the pressure core.

    Analysis on VSP Features of the Lithologic Rocks in the Main Hole of Chinese Continental Scientific Exploration
    YANG Zheng-Hua, SHU Guang-Meng, ZHOU Xiao-Wei
    2009, 23(6):  1153-1159. 
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    The main hole of Chinese Continental Scientific Drilling (CCSD) is located at Donghai County which is in the eastern side of the Tanlu fault and is at the southern part of Sulu ultrahigh pressure metamorphic belt. The VSP survey is one part of the multi-scientific research. The hole has been surveyed by employing digital seismic instrument (HF300) and digital three-component geophone technique(GeoChain). Combining the VSP surveying results and the 5,000-meter lithologic characteristics of the hole, the features of lithology grouping, seismic responses of ultrahigh-pressure metamorphic rocks, and the relationship between vp/vs and lithology have been analyzed, it comes to a conclusion that: (1) it is advisable that metamorphic rock is grouped by the characteristics of distribution and association of eclogites, because the VSP velocities match well with logging density and lithology distribution in each group;(2) all the eclogite-gneiss interfaces and the shear zones can generate strong reflections, the orthogneissparagneiss interfaces can form obvious reflections, and sometimes the reflection events of lending or banded rocks are bending, while the reflection events of shear zones are continuous; and (3)the eclogites are characterized with high velocity (6.3 km/s), low vp/vs ratio(1.2), and strong and sparse wave trains, while the paragneisses with middle velocity (6.1 km/s) and high vp/vs ratio (1.8) and sparse wave trains, the orthogneisses with low velocity (5.8 km/s) and middle vp/vs ratio (1.5) and dense wave trains; and the shear zones have the characteristics of the strong reflections and the highest vp/vs ratio (2-2),the vp/vs ratio of shear zones is high, no matter what kind of rocks they emerge in. The research results can not only discover the seismic responses of ultrahigh-pressure metamorphic rocks, but also and more significantly, provide evidences for 2D or 3D surface seismic interpretation, decrease the ambiguity and uncertainty of interpretation, enhance the reliability of geological structure interpretation in CCSD region. 

    Seismic Modeling Method for Shallow Seismic Exploration of  Buried Active Fault
    LAN Xiao-Wen, Yan Xin-Fei, WU He-Zhen, TIAN Jia-Yong, NIU Bin-Hua
    2009, 23(6):  1160-1166. 
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    The shallow high-resolution seismic prospecting is one of the effective and reliable methods in urban active fault detection. For the shallowness of the object stratum, the tiny difference between the seismic attribute of strata and the ambient noise, it is hard to process and interpret seismic data. In this paper, the staggered-grid high-order difference method of one-order elastic wave equations, which are expressed with velocity and stress applying the flux-corrected transport(FCT) method with a perfectly matched layer (PML) absorbing boundary condition, are used to obtain the synthetic common-shot profile for shallow fault model. The simulated results of fault model show that this method is accurate and distinct. This seismic modeling method is helpful for approximately estimating the location, the depth and the scope of the fault from the synthetic profile during survey, and improving the efficiency of seismic prospecting and the precision and resolution of seismic data processing and interpretation.

    Hydro-physico-chemical Variations of the Karstic Spring and Its Environmental Effects in Ridge-trough Area, Eastern Sichuan
    —A Case Study on Jiangjia Spring in Qingmuguan Karst Valley, Chongqing
    HU Zhi-Yong, YANG Ping-Heng, YANG Mei, LUO Jian-Yin, LI Yuan-Qing
    2009, 23(6):  1167-1173. 
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    The groundwater is always polluted to some extent by pesticides and fertilizers. There are few researches on monitoring of groundwater in karst areas at present. This paper presents a case study on the Jiangjia spring in Qingmuguan karst valley experimental site,Chongqing, China. Rainfall and physico-chemical variations of groundwater are monitored by the HOBO weather station. The CTDP300 multi-parameter auto-recordable instrument and NITRATAX plus sc online NO-3-N analyzer are employed in different rainfall conditions at Qingmuguan karst valley. The results show that the karst dynamic system is very sensitive to the environment and responds promptly. The spring's pH value decrease, as it is diluted by the acid rain. The water temperature changes owing to rainfall, duration, and air temperature. Electrical conductivity changes with rainfall environment. The dilution function of the rainwater mainly occurres in the initial stage under normal rainfall environment and the crevasse watery medium plays a key role in the next stage.The chemical characteristics of water seepage is mainly controlled by the rainwater under rainstorm environment and the pipeline watery medium plays a key role. Positive correlation exists betweenNO-3 and electrical conductivity,and both of them are significantly correlated to the amount of rainfall. It indicates that the rainfall is a very important factor to contaminated groundwater, and can also result in the missing of the soil and nutrition element.The research of the underground river is important in solving residents potable water, conserving groundwater and preventing the soil from desertification.

    Study on Fe Occurrence and Geochemical Simulation of Groundwater in the Deep Confined Water in Zhanjiang
    YAO Jin-Mei, ZHOU Xun, XIE Chao-Hai
    2009, 23(6):  1174-1179. 
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     A regional depression cone exists in groundwater level in the deep confined water owing to a long- term exploitation of groundwater in Zhanjiang, Guangdong. The formation of the depression cone has a certain effect on the chemical nature of groundwater in the deep confined water, resulting in low concentration of Fe in the western and northwestern parts, high concentrations of Fe in the northern part and medium concentrations of Fe near the center of the depression cone. Geochemical simulation was carried out for the Fe occurrence in groundwater in the depression cone. The results show that groundwater in the depression cone in the deep confined water  may be supplied from groundwater in the north, northwest and west, or from groundwater in the shallow confined aquifers.Groundwater in the deep confined water  is a mixture of the supplied groundwater, and the high Fe groundwater is a main source. Groundwater exploitation of large quantity in the deep confined water  causes an increase in Fe contents in the groundwater. In the course of groundwater towards the center of the depression cone, not only the dissolution of calcite, dolomite and hematite, the precipitation of siderite and melanterite may occur, but also the cation exchange between Na+ and Ca2+, Fe oxidation- reduction of Fe may occur.

    Experimental Study on Salt Pollution for Groundwater Recharge with Reclaimed Water in Area of Chaobai River
    YAN Yong-Sheng, HE Jiang-Tao, ZHENG Fan-Dong, XIONG Yan-Na, SONG Bo
    2009, 23(6):  1180-1184. 
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    According to engineering geologic investigation and sample test analysis, reclaimed water of Chaobai River in Shunyi, Beijing was selected to take three kinds of typical representative soil medium (sandy gravel, fine sand, silty clay) to install the soil column, and was used to carry on the leaching simulation test. The column test results show that the cation exchange adsorption mainly manifests the K+and Ca2+ exchange in three kinds of typical soil medium, and the cation exchange function compares the sandy gravel column and the fine sand column is more remarkable  in the silty clay column. Moreover, the column test results also indicated that, with increasing of clay content, total organic compounds (TOC)cation exchange capacity (CEC) and total amount of clay minerals, in the typical medium leaching simulation column experiment, the cation exchange functions equilibrium time is also longer, and is 72 days for the sandy gravel,80 days for the fine sand and 86 days for the silty clay, respectively. The quantificational results computation has also proven the above conclusion: the background value of various anions and cations concentration of the silty clay medium is highest; the contribution quantity of the hardness of the unit mass silty clay medium and the total dissolved solids (TDS) is biggest, and is 5,767 mg/g and 6,952 mg/g, respectively.

    Frontier Research on the Impact Extent of Geological Environment During the Development and Utilization of Shallow Geothermal Resources
    GAO Xin-Yu, FAN Bo-Yuan, ZHANG Hong-Guang, YU Yuan, ZOU Yuan-Lin
    2009, 23(6):  1185-1193. 
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    Combining with projects of development and utilization of shallow geothermal resources that have been carried out, based on the collection and analysis of geology, hydrogeology and groundsource heat pump project information,  GSHP (ground source heat pump)monitoring systems including a groundwater GSHP monitoring station, a ground pipe GSHP monitoring station, as well as 20 GSHP monitoring points are set up. Through laying temperature sensors and data collection devices, we can realize dynamic monitoring, and adopt GPRS wireless transmission system to achieve longdistance transmission of monitoring data. Finally, according to analysis of monitoring data, the impact extents of the geological environment on the development and utilization of the shallow geothermal resources are assessed.It is concluded that the changes of soil temperature field are related to depth,and the changes of ground temperature are also associated with the system heat transfer power.

    Recharge to Shallow Aquifer to Control Land Subsidence due to Construction in Shanghai City
    WU Jian-Zhong, WANG Han-Mei, YANG Tian-Liang
    2009, 23(6):  1194-1200. 
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    Land subsidence in Shanghai is mainly affected by groundwater withdrawal and large-scale construction. Land subsidence occurred by large-scale construction becomes increasingly obvious with the enforcement of groundwater withdrawal management, and affects the safety of construction and working of surrounding lifeline engineering. The study of mechanism and prevention of land subsidence due to construction is low, and the prevention technological system hasn`t been built. To control land subsidence occurred by construction dewatering, this paper introduces the mature technology of artificial recharge in deep confined aquifer to shallow aquifer via test study. Because the sand stratum structure and hydrodynamic condition of shallow aquifer is different with the deep one, the technics and methods of artificial recharge is also different. This test improve on the technics and methods of artificial recharge to suit the shallow aquifer, and monitoring the land surface deformation synchronously to analysis the effect of artificial recharge. To generalize the application of artificial recharge to shallow aquifer, this paper discussed the feasibility and applicability of adopting artifical recharge technology to shallow aquifer in Shanghai.