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SequenceStratigraphic Features and Their Paleogeographical Implications for the Mesoproterozoic of the Southern Margin of Wutai Mountain: A Case Study of the Chenjiazhuang Section in Wutai County of Shanxi Province, North China MEI Min-Xiang Geoscience    2010, 24 (5): 888-899.   Abstract （19338）      PDF（pc） （14980KB）（49638）       Knowledge map    Save The study area, i.e. the southern margin region of the Wutai Mountain, is a conjoining region between the Jin-Yu-Shan in the southern part and the Yanliao Rift Troughs in the northern part of the Mesoproterozoic in the North-China Craton. A set of clastic rocks of the tidalflat deposition system makes up the Changzhougou Formation, and a set of tidalflat carbonate rocks does the Gaoyuzhuang Formation, both of which constitute the Mesoproterozoic of the study area. Its bottom boundary is an angular unconformity covering the Paleoproterozoic Hutuo Group, and top boundary is a leurodiscontinuity with a stratigraphic hiatus more than 1,000 Ma underlying the Cambrian system. Thus, the incomplete strata of the Mesoproterozoic become a true example for the study of sequence stratigraphy in the Precambrian, which is the key to peek the trangressive process from the Jin-Yu-Shan in the southern part in the early period and that from the Yanliao Rift Troughs in the northern part during the Mesoproterozoic in the study area, and provides a valuable stratigraphic record to correlate strata that remain uncertain. Further, the research and introduction on sequence-sequence features that are marked by depositional successions for the Mesoproterozoic at the Chenjiazhuang section in Wutai County of Shanxi Province will provide a useful clue for further study on the Precambrian sequence stratigraphy in the North-China Craton. Reference | Related Articles | Metrics | Comments（0）

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Geologic Characteristics, Sulfur and Lead Isotope Study of the Shalitashi Lead-zinc Deposit, Southern Tianshan ZHANG Shu, ZHANG ZHao-Chong, HUANG He, ZHANG Dong-Yang, XUE Chun-Ji Geoscience    2010, 24 (5): 856-865.   Abstract （11538）      PDF（pc） （11251KB）（33047）       Knowledge map    Save  The Shalitashi lead-zinc deposit located in Xinjiang Uygur Autonomous Region, NW China is an important lead-zinc deposit in the southern Tianshan polymetallic metallogenic belt. The deposit occurs in the Paleozoic Maidan-Kuokeshale basin as lens, nested and tubular orebodies within the structure fracture zone in the dolomite of the middle Devonian Tuogemaiti Formation. The alteration is weakly developed in the wall rocks. The dominant sulfide minerals in the ore are sphalerite and galena. The ore structures include open-space filling and host-rock replacement. The δ34S values for the sulfide minerals range from -3.6‰ to -12.0‰ which indicates that the reduced sulfur is derived from the seawater sulfate. The 206Pb/204Pb values for sulfides range from 17.8979 to 17.9625，207Pb/204Pb from 15.5981 to 15.6023，208Pb/204Pb from 31.1863 to 38.1971, which implies that the metals were derived from the sediments with high metal contents in the Paleozoic basin. On the basis of the geology and geochemistry characteristics, the Shalitashi leadzinc deposit can be classified into Mississippi valley-type lead-zinc deposit. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Controls of Plate Motions on Subsidence and Filled Characteristics of  the Cenozoic in Chinese Offshore Basins LI Yun-Zhen, DENG Yun-Hua, XU Qiang, YU Xin-He Geoscience    2010, 24 (4): 719-726.   Abstract （18816）      PDF（pc） （11556KB）（31693）       Knowledge map    Save  The evolutions of the Pacific Plate, the Indian Ocean Plate and the Eurasian Plate have the controlling effect to the subsidence and filled characteristics of the Cenozoic in Chinese offshore basins.According to the characteristics of mantle convection and crustal stretching, the subsidence types of Chinese offshore basins can be divided into passive, initiative and combination thermal subsidences. The different subsidence types of sedimentation basins have different basin structures. Rift is the main type in the passive thermal subsidence. Depression is the main type in the initiative thermal subsidence. Vertical or lateral overlapping is the main type in the combination thermal subsidence. The passive thermal subsidence is the main type in northern Chinese offshore basins in internal plates. As away from the sea, these basins are less affected by the transgression which is dominated by the continental sedimentary system. Central Chinese offshore basins in plate margins have the subsidence characteristics which the initiative overlaps the passive in a lateral direction with shallow water, small slope break and delta. Southern Chinese offshore basins in plate margins also have the subsidence characteristics which the initiative overlaps the passive in a lateral direction with deeper water, large slope break and delta. Reference | Related Articles | Metrics | Comments（0）

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Sedimentary Characteristics and Stratigraphic Correlation of the Late Precambrian Strata in Guozigou of Yili，Xinjiang FENG Bo1,2，LIN Jin-yan1,2，NIE Li1,2，MA Shang-wei1,2，LI Ying1,2 Geoscience    2013, 27 (4): 959-967.   Abstract （8083）      PDF（pc） （13203KB）（25375）       Knowledge map    Save Guozigou in Yili of Xinjiang is located at the west margin of north Tianshan. The Precambrian strata in Guozigou are exposed relatively completely，which can be subdivided into Kayingdi Formation，Tarqiate Formation and Talisayi Formation from bottom to top. Kayingdi Formation and Tarqiate Formation are interglacial deposits，and Talisayi Formation is a glacial deposit. Kayingdi Formation mainly consists of argillaceous siltstone，silty mudstone，lithic sandstone and feldsarenite，in which sedimentary structures are developed，including parallel bedding，horizontally laminated bed，flaser bedding，sand lens and trough cross stratification. Kayingdi Formation can be subdivided into littoral subfacies (mixed flat microfacies and sand flat microfacies) and neritic shelf subfacies (normal neritic microfacies and storm deposit microfacies). Tarqiate Formation consists of argillaceous siltstone and silty mudstone with high shale content，in which a great quantity of horizontally laminated beds are developed，and this formation is a shallow-marine detrital deposit with three sedimentary sequences from deep to shallow. Talisayi Formation is a tillite deposit and can be subdivided into basal till subfacies，proglacial littoral subfacies and typical ice rafting-marine subfacies. According to sedimentation type，depositional combination，sedimentary facies and stratigraphic correlation with Quruqtagh area in Xinjiang，and combined with previous research results，it is inferred that these strata belong to Nanhua System. Meanwhile, Kayingdi Formation and Tarqiate Formation can be correlated with Huangyanggou Formation in Quruqtagh area，and Talisayi Formation can be correlated with Teruiaiken Formation. The existence of the ancient land in the study area is also discussed by analysis of Nanhua System petrology, and the evidence is provided in the end. Reference | Related Articles | Metrics | Comments（0）

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Geoscience    2014, 28 (6): 0-.   Abstract （887）      PDF（pc） （6929KB）（23821）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Geochemical Features and Tectonic Significance of the Alkali-Basalts from Ji’an-Taihe Basin,Jiangxi Province YU Xin-qi，SHU Liang-shu，DENG Guo-hui，WANG Bin，ZU Fu-ping Geoscience    2005, 19 (1): 133-140.   Abstract （10695）      PDF（pc） （549KB）（23801）       Knowledge map    Save New found basalt crop is located near the Nanxi Town, Taihe County, south of Ji'an-Taihe Basin, middle Jiangxi Province. With brown-grey and dark green color, the fresh basalt has compacted texture and some blisters and amygdules. Microscope observation reveals that the rocks have intergranular textures,more than 60% basic plagioclases, filling with olivines and augites, less than 5% almond-shaped calcites, and weak corrosion. According to its geochemical features, the basalt belongs to alkalibasalt, produced by quick regional extension within a plate. Rb-Sr and Sm-Nd isotopic composition of the basalt are as follow:(87Sr/86Sr)i =0.704 1-0.704 8 and εNd(t)=+3.78-+4.38, indicating that the magma came from the deficit mantle and had not mixed with crust material. The zircon solution U-Pb geochronological data of(139±0.7)to(143±1.1)Ma for the alkali-basalt indicates that mantle-reached strike-slip faulting along northeast-striking Ganjiang Fault and Wuchuan-Sihui Fault was active from early period of Early Cretaceous under the extensional background of the area Related Articles | Metrics | Comments（0）

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Subducting Characteristic of the Pacific Slab Beneath Northeast China JIANG Guo-Meng, ZHANG Gui-Bin, XU Yao Geoscience    2012, 26 (6): 1125-1135.   Abstract （19092）      PDF（pc） （12400KB）（21975）       Knowledge map    Save  The volcanoes locating in northeast China are very active. Some researchers consider that the origin of volcanoes is closely related to the subducting western Pacific plate and the upwelling asthenosphere. The thickness and the existing range of the subducted plate are not clear as far although the seismic tomography results obviously show that the Pacific plate exists below the volcano region. Therefore, in this study, we adopted the method combining the teleseismic tomography with travel time forward modeling to further study the velocity structure beneath northeast China, especially the precise model of subducted Pacific plate. Our results show that (1） the average thickness and velocity perturbation of slab are 85 km and 1%, respectively, and the slab has not been thickened compared with the previous result of the Japan Sea; (2） the Pacific plate subducted into the mantle transition zone with a shallow dip angle, and changed horizontally when it touched the bottom of mantle transition zone, and extended westward to Longitude 127°E and then stops over there; (3） the horizontal slab locates right below the volcano region. These above features help people understand the origin of intraplate volcanoes and the geodynamical process better. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Recharge to Shallow Aquifer to Control Land Subsidence due to Construction in Shanghai City WU Jian-Zhong, WANG Han-Mei, YANG Tian-Liang Geoscience    2009, 23 (6): 1194-1200.   Abstract （18576）      PDF（pc） （5791KB）（21574）       Knowledge map    Save 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. Related Articles | Metrics | Comments（0）

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Synopsis of Petroliferous Basins and Petroleum Distribution in South America BAI Guo-ping, QIN Yang-zhen Geoscience    2010, 24 (6): 1102-1111.   Abstract （14124）      PDF（pc） （15954KB）（20358）       Knowledge map    Save South America is one of the major oil and gas producing regions. It has recorded a number of significant exploration breakthroughs recently. Since 2007, several giant fields have been discovered in the sub-salt sequences in the Santos Basin, which indicates the promising exploration potential of sedimentary basins in South America, particularly deep water sub-salt play in the passive margin basins. Based on the up to date reserve data of oil and gas fields, this paper documents the oil and gas distribution features in terms of basin type. It also characterizes the areal and stratigraphic distribution of discovered oil and gas reserves. In South America, the foreland basin is the basin type with the richest oil and gas resources, followed by the passive margin basin. The foreland basins are located along the Andes Mountains. The ones in the northern and southern sectors are Cenozoic foreland basins and those in the middle sector Paleozoic foreland basins. The foreland basins which evolved from a proceeding passive margin basin development stage are the most prolific oil and gasbearing basins. They are represented by the East Venezuela and Maracaibo Basins. Along the Andes foreland basins, the main reservoir intervals vary from the Jurassic-Cretaceous in the south, through the Carboniferous in the middle, to the Cretaceous-Tertiary in the north. The passive margin basins lie along the South Atlantic margin. In this type of basins, oil and gas are mainly concentrated in the Cretaceous-Tertiary. Of them, the ones with evaporites tend to be richer in oil and gas and they are represented by Campos and Santos Basins. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(10)

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Some Key Tectonic Characteristics of Chinese Foreland Basins and Related Petroleum Geology LI Ben-Liang，WEI Guo-Ji，JIA Cheng-Zao，GUAN Shu-Wei，SHI Xin Geoscience    2009, 23 (4): 575-586.   Abstract （13554）      PDF（pc） （11182KB）（19416）       Knowledge map    Save This paper concludes some key geologic characteristics of Chinese foreland basins based on the study of the sedimentary infill, tectonic evolution, tectonic dynamics，spatial location distribution and structural deformation geometry. The foreland basin is super imposition with the compression sedimentary stratigraphic sequence over the extension basin. Four-stage structural deformation of foreland basin and thrust-fold belt has occurred since Protozoic. The foreland basin developed under the control of two factors which are basin basement collaged by many small plates or terrains and the distance effect of India-Eurasia collision, so all the foreland basins and the rejuvenative ancient orogenic belt make up a giant basin-mountain system which locates at the outer circus of Tibet plateau. There are many structural styles of the thrust-fold belt in different basins. These tectonic characteristics result in the regularity and complexity of oil pooling. The regularity includes:(1) the orders of oil/gas spatial distribution from thrustfold belts to Craton, (2)the availability of match among the petroleum pooling factors and accumulation dynamic qualifications, (3)regional sequences of target reservoirs in the whole western China, and (4)many periods of hydrocarbon generating but pooling late. The complexity manifests itself in four ways:(1)the difference of the geologic features of fourstage structural deformation,(2)the deformation and disruption of petroliferous reservoir and pool,(3)inhomogeneous reservoir resulted from nonmarine sedimentary, and (4)difficulties to define the structural traps resulted from strong deformation in the thrustfold belts.   Related Articles | Metrics | Comments（0） Cited: Baidu(46)

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Study on Thrust Nappe and Sliding Nappe Structures of Mesozoic-Cenozoic in the Nancheng Area, Jiangxi Geoscience    2016, 30 (1): 97-109.   Abstract （9550）      PDF（pc） （4923KB）（19297）       Knowledge map    Save Based on geological surveying and drilling verification of stratum contact relations both between Jurassic Linshan Group and underlying Pre-Jurassic metamorphic strata and between Cretaceous and Pre-Cretaceous strata, this study has newly found the Xiejia structural window, Zhuyouxincun structural window, Shangwushi structural window and Wangtianshi klippe, and moreover, has determined the Yanshanian glide and Himalayan thrust nappe structures in Nancheng area, Jiangxi. The Yanshanian glide structure occurred in the end of Middle Jurassic along the expanding surface from unconformity surfaces between D-T2/T3-K1 (gliding nappe) and lower strata (underlying strata). The dynamics of glide structures maybe relate to the subduction of Pacific plate from southeast toward northwest. The large-scale Himalayan thrust nappe structure had thoroughly altered the former strata sequence and formed present tectonic framework. This framework is composed of multiple imbricated thrust and stacking faults (bedding and crossbedding) and behaves a feature of lateral zonation and vertical stratification. The allochthon Pre-Cretaceous mass thrusts from southeast toward northwest and stacks on the autochthon Cretaceous strata. The autochthon Cretaceous strata exhibit some windows around by Pre-Cretaceous. The dynamics of Himalayan thrust nappe structure is complicated and maybe relate to the distant effect of the collision between the Eurasian plate and the Indian plate. Related Articles | Metrics | Comments（0）

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The Exhalativesedimentary Evidence of the Bainiuchang Ag-polymetallic Deposit, Yunnan, China: Constraints from Geochemistry of Host-rocks ZHU Chao-hui, LIU Shu-xia, ZHANG Qian, GU De-min Geoscience    2010, 24 (1): 120-130.   Abstract （23228）      PDF（pc） （9690KB）（19240）       Knowledge map    Save Studying if there took place extensive exhalative-sedimentary activities in the southeast Yunnan Province has been one of key factors to constrain origin of the Gejiu, Bainiuchang, and Dulong polymetallic deposits. The authors systematically study the geochemistry characteristics of host-rocks in the Bainiuchang Ag-polymetallic deposit in this paper. The host-rocks have the same distribution area with the sea-floor volcano or hotwater origin chert. Then normalized REE distribution patterns of hostrocks can be divided into two groups: One group with higher total REE contents indicates more normal sediments attendance. The other group with lower total REE contents possesses the similar normalized REE distribution patterns and parameters with rich-tourmaline banded hydrothermal sediments in the Canada Sullivan deposit and banded chert in iron-bearing formations in the Canada Agnico-Eugle deposit. And the pairs of trace elements show the similar characteristics with modern sea-floor hydrothermal sediments. In addition, the contents of As, Sb and Ag are similar with that of chert in the Dachang and the Gejiu mining districts. Based on above of all, it is indicated that the Bainiuchang Ag-polymetallic deposit is exhalative-sedimentary origin. Related Articles | Metrics | Comments（0）

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Study on the Evaluation Method of Fault Sealing and Its Application: An Example of Neogene Layer in Enping Sag, Pearl River Mouth Basin Geoscience    2016, 30 (1): 122-129.   Abstract （9316）      PDF（pc） （2853KB）（19153）       Knowledge map    Save Taking the Neogene layers of the Enping sag as an example, a new way to evaluate fault sealing of structural closure is introduced under the current exploration practice to calibrate critical values, that is, obtaining clay content in fault zone, shale smear value and normal pressure of fault surface from sealing rules of faulted reservoir. The results show that the threshold values of shale smear factor in drilled faulted reservoirs gradually increases with depth. Development of shale and its content of fault zone are prerequisites for fault sealing, and the evaluation of fault sealing is affected by structure map accuracy, structural adjustment and fault activity. The risk of fault sealing, including faults vertical and lateral sealing, could be analyzed by the evaluation method, so as to improve the success ratio of fault traps exploration. And the evaluation method could be applied to the new exploration area with the similar tectonic genesis and sedimentary background as Enping sag, which is an effective methods to evaluate fault sealing during the early exploration periods. Related Articles | Metrics | Comments（0）

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Geoscience    2016, 30 (1): 0-.   Abstract （9419）      PDF（pc） （3280KB）（18984）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Geochemical Characteristics and Tectonic Implication of Rilang Formation Basalt in the South Tibet, Zhongba County, Tibet, China Geoscience    2016, 30 (1): 69-77.   Abstract （9606）      PDF（pc） （4324KB）（18926）       Knowledge map    Save Lower Cretaceous volcaniclastic litharentites are widely distributed in the Tethyan Himalaya, while less research was reported about the provenance of these volcaniclastic litharentites. In this paper, we report sedimentray and geochemical characteristics of basalts in Rilang Formation of central-western Tethayan Himalaya. Major and trace element compositions show that these basalts belong to alkaline basalt. They are enriched in LREE relative to HREE, similar geochemically to Ocean Island Basalt (OIB) and intra-plate basalt. The contents of Nb fall between the upper crust and lower crust. These basalts have a relatively low content of Th than that of lower crust and relatively high Th/Nb ratio, low Ce/Pb ratio,which indicates that these basalts suffered variable crustal contamination. Sedimentary and geochemical characteristics of these basalts are apparently different from seamounts basalt in the Yarlung-Zangbo ophiolitic mélange belt. The tectonic setting discrimination diagrams based on trace elements suggest that basalts of the Rilang Formation formed in intracontinental rift environment. Combining the petrology and depositional environments of sedimentary rocks, we conclude that these basalts maybe the one of the provenance of volcaniclastic litharentites of the Rilang Formation. Related Articles | Metrics | Comments（0）

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Pop-up Structure in Fold-and-thrust Belt and Its Implications: An Insight from Analogue Sandbox Models of Thrust Wedge Geoscience    2016, 30 (1): 110-121.   Abstract （9671）      PDF（pc） （8533KB）（18887）       Knowledge map    Save Pop-up structure is widely developed in fold-and-thrust belt and strike-slip tectonic setting, and has been paid much attention for its great significance in petroleum exploration. Analogue sandbox modeling has proved to be a powerful visual tool for simulating such complex structures in various tectonic settings. This study conducted a series of sandbox modeling to unravel the difference in structural geometry of pop-up structure during the development of fold-and-thrust belt, based on the same initial condition with various shortening velocities (0.3 mm/s, 0.1 mm/s, 0.005 mm/s). From the modeling results, two types of pop-up structures, i.e. superimposed and simple pop-up structures, would be developed in thrust wedge depending on different shortening velocities. In particular, there is a significant difference between superimposed structure and simple pop-up structure. The wedge shows simple deformation styles characterized by simple pop-up structures and increasing deformation while propagating continuously towards foreland. The propagation way of analogue sandbox models of thrust wedge has a significant control on the types of pop-up structure. Forward-breaking propagation took place in the foreland, mainly developed from simple pop-up structure; back-breaking propagation occurs in hinderland, mainly developed from superimposed pop-up structure. Related Articles | Metrics | Comments（0）

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Sedimentary Sequence and Environment of Shuangqiaoshan Group from the Adjacent Area Between Anhui and Jiangxi Geoscience    2016, 30 (1): 130-143.   Abstract （9722）      PDF（pc） （2215KB）（18840）       Knowledge map    Save The adjacent area between Anhui and Jiangxi is located in the northern margin of the eastern section of Jiangnan orogenic belt, in which Shuangqiaoshan Group is widely distributed in a large-thickness and low-grade greenschist-facies metamorphic flysch formation which is given priority to with argillaceous-arenaceous metamorphosed fine clastic rocks and contains a small amount of volcanic rocks. Synthesizing analysis of rock assemblages and sedimentary structures shows that Shuangqiaoshan Group may be formed in a set of volcanic-terrigenous clastic rocks which can be divided into four stages of sedimentary facies about the bathyal-shelf margin slope, neritic shelf, shelf slope and shelf slope-shelf facies under tectonic background of continental margin island arc, indicating the shrinking-closing stage of the basin evolution during the period. The proximal source region and discontinuous incomplete Bouma sequence of Hengyong Formation and Anlelin Formation, mainly generated by turbidity current and few by sandy debris flow, respectively formed during the northward limited subduction process of the lithospheric fault block in South China with oceanic crustal sea areas, and after that under ocean-basin thinning regressive environment in Neoproterozoic. From the perspective of volcanism with sedimentation co-evolution on the relationship between the sedimentation and tectonic analysis, the volcanic activity resulted from oceanic crust subduction may be started from southwest of the study area. This study provides the important evidence for the geotectonic evolution of the Neoproterozoic in the adjacent area between Anhui and Jiangxi from the aspect of the sedimentary stratigraphy. Related Articles | Metrics | Comments（0）

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An Improved Lithological Classification Method for Thermal Infrared Hyperspectral Data Based on Spectral Matching Geoscience    2016, 30 (1): 239-246.   Abstract （9727）      PDF（pc） （11135KB）（18622）       Knowledge map    Save Feature spectral characteristics are the base of hyperspectral remote sensing technology. Based on rock spectral characteristics, for the purpose of classifying lithology by using Thermal Infrared Airborne Hyperspectral Imager (TASI) data, an improved lithological classification algorithm-spectral divergence energy-level matching (SDEM)-is presented in this paper. SDEM can identify tiny differences between any two different spectra. Also, this method takes both spectral band intensity and spectral waveform into account, and can effectively reduce the impact of image noises. Compared with the traditional lithological classification method-high spectral angle mapping (SAM), the improved algorithm can distinguish those similar but different spectra more precisely, and can identify those easily confused lithology. This method is also good at distinguishing the lithology known as “different features with similar spectra”. Using the TASI data of Liuyuan region in Gansu Province, we compared the lithological classification results of SDEM and SAM methods, and found that the SDEM method can identify the lithology that SAM can’t identify or wrongly identified. Based on our field validation work, the classification result by SDEM is more accordant with the actual distribution of rock, and is also more detailed. Related Articles | Metrics | Comments（0）

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Geochemical Characteristics and Tectonic Implication of Basalt in Lower-Middle Jurassic Sewa Formation in Renacuo Area of Gaize, Tibet, China Geoscience    2016, 30 (1): 78-86.   Abstract （9848）      PDF（pc） （34784KB）（18314）       Knowledge map    Save The trachy basalt was discovered in Lower-Middle Jurassic Sewa Formation in Renacuo area of Gaize, Tibet. The contents of SiO2, Al2O3, Na2O and K2O are 45.62%-48.46%, 14.09%-16.51%, 2.68%-4.12%, 1.35%-4.73%, respectively, and the ratio of K2O to Na2O (K2O/Na2O) is 0.34-1.77. The rocks are rich in LREE, and poor in HREE with a weak positive Eu anomaly, as well as an enrichment of elements such as Rb, Ba, U and a depletion of elements like Sr, Yb, Th, Y as a whole. The geochemical characteristics indicate that they are generated in oceanic island environment within the oceanic slab, and that the magma is derived from enriched mantle without or with a little contamination of crust materials and sub-continental lithosphere. The oceanic island rock combination consists of basalt, basaltic gravel and limestone. Combined with the idea that Sewa Formation is seafloor fan sedimentary environment, it can be inferred that the Bangong-cuo-Nujiang ocean was mature oceanic crust in Early-Middle Jurassic. Related Articles | Metrics | Comments（0）

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Formation Mechanism and Characteristics of Non-tectonic Fractures in Shales Geoscience    2016, 30 (1): 155-162.   Abstract （11823）      PDF（pc） （1952KB）（17817）       Knowledge map    Save Non-tectonic cracks are commonly observed in shale and some of them are greatly significant for the evaluation of shale gas accumulation and preservation. On the basis of the previous research and considering the inherent characteristics of shale, a category scheme of shale fractures has been put forward, and the forming mechanisms of the non-tectonic shale cracks has been summarized. According to the core and field observations, we briefly depicted the characteristics of the non-tectonic shale cracks. Among the non-tectonic cracks of shale, those bedding cracks formed in the diagenesis and those overpressure fractures induced by undercompaction or hydrocarbon generation have close relationship with shale gas accumulation and preservation. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Dating for Ore-hosting Rock of the Gangcha Gold Deposit in Western Qinling Mountains and Its Geological Significance Geoscience    2016, 30 (1): 36-49.   Abstract （11747）      PDF（pc） （6318KB）（17348）       Knowledge map    Save Gangcha gold deposit is a new medium-sized gold deposit which was found in the northern margin along western segments of Western Qinling Mountains, and it is expected to be a larger scale. There are five ore veins in the deposit, which are limited by the fault zones. The shallow part of host rocks are the volcanic and volcanic clastic rock group. The sets of the volcanic rock groups have been identified as Lower Jurassic Langmusi Formation for a long time before. In fact, those are confirmed as Triassic with the age of (245±2) Ma by zircon U-Pb dating method applied to the tuffs in the group this time. Also, there are two kinds of intruded rocks which are granodiorites and quartz diorites in the deposit, and the both ages are confirmed as (242±2) Ma and (246±3) Ma by zircon U-Pb dating method, respectively. That means that those intrusive bodies and ore-hosting volcanic rock group are same magmatic activity products in Indo-Chinese epoch. Above results limited that the Gangcha gold deposit was formed under magmatic hydrothermal activities after tectonic magmatic activity of Early Triassic period. The study conclusion can provide new facts for advancing gold deposit genesis research and clearing exploration direction. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Evolution of Yanshanian Granites in Southern Marginal Region of North China Block：A Case Study of XiaoqinlingWaifangshan Area WANG Zhen-Jiang , XU Jian-Chang, FENG Jian-Zhi , QI Dong-Mei, YANG Gang, SUN Wei-Zhi Geoscience    2011, 25 (6): 1032-1046.   Abstract （11120）      PDF（pc） （10231KB）（17331）       Knowledge map    Save According to the time and space distribution characteristics of Mesozoic granites in XiaoqinlingWaifangshan  area in southern marginal region of North China block，the forming process of the Mesozoic granites can be divided into 160-155 Ma(Ⅰ), 150-125 Ma（Ⅱ）, and 120-110 Ma（Ⅲ），not identical with largescale magmatic activity periods of North China. The geochemical evolution of the three periods of granites are special: geochemical  characteristics of Ⅰ and Ⅲ periods of granites are very similar，and they are abnormally high content of K, obvious negative Eu anomaly and weak heavy rareearth fractionation, belonging to Atype granites. Ⅱ period of granite is metaluminousperaluminous and high potassium calcium alkaline series granite, and is rich in big ion lithophile element，such as K, U, and Th，lack in the high field element. P2O5 content decrease with the increasing of SiO2 content, belonging to Itype granite. For the contents of most samples, Sr content is more than 300.00×10-6，Y content is less than 19.00×10-6 and Yb content is less than 1.90×10-6, showing the geochemical characteristics of adakite rock. From early to late period，Ⅰ,Ⅱ and Ⅲ periods of granites show the trend of Atype-Itype-Atype. I period of granite formed in local extensional environment under the extrusion tectonic background. Ⅱ period of granite formed in tectonic setting transition period，being the product of the lower crust melting led by thickening crust. Ⅲ period of granite formed from plate stabilization, lithosphere stretching, and decompression and melting of the lower crust rocks, after Yangtze and North China continental blocks fitting. Reference | Related Articles | Metrics | Comments（0）

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Distribution of Kaolinite and Its Influencing Factors in the Reservoir of Shahejie Formation in Dongying Depression GUO Jia，ZENG Jian-hui，SONG Guo-qi3，ZHANG Yong-wang，WANG Xue-jun，MEND Wei Geoscience    2013, 27 (5): 1089-1098.   Abstract （11791）      PDF（pc） （10925KB）（17260）       Knowledge map    Save Kaolinite widely distributed in the sandstone reservoir of the Shahejie Formation in Dongying depression，which is an important factor affecting the reservoir physical properties. But the research on its distribution characteristics and controlling factors is less comparatively. This paper goes on to research the distribution characteristics and controlling factors of kaolinite by analyzing the data from casting lamella，X-ray diffraction，cathode luminescence image，electron scan microscope. Research results show that kaolinite mainly developed in the range of depth 1，200一3，600 m. The average relatively content of kaolinite are much higher in Es2 and Es 3 .As to the kaolinite content in Es1 to Es3，the central uplift belt is higher than northern steep slope and southern ramp zone of Dongying depression. Distribution of kaolinite in the sandstone reservoirs of Shahejie Fororation is obviously affected by thermal evolution of organic matter. Different temperatures(buried depth)affect the content of kaolinite in different horizons of Shahejie Formation and its distribution in plane and profile by controlling the formation and transformation of clav minerals .The overpressure has an important influence or the distribution of kaolinite. Due to overpressure，the overpressured top boundary is generally characterized by well-developed kaolinite. Tectonic activity of central uplift belt of Dongying is strong，which is advantageous to the acidic fluid from deep to shallow filling. And hydrodynamic force is strong，leading to kaolinite content in Es1 to Es3 of the central uplift belt is higher. The pathway system composed of fault and unconformitv surface transport a large number of acidic fluid into the shallow reservoirs，which lead to considerable development of kaolinite. Lithology and sedimentary microfacies change the fluid chemistry and hydrodynamic conditions，thus has an important influence on kaolinite distribution. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Relationship Between Granophyre and Molybdenum Ore of Wangwu Mining District in North Wuyi Region: Evidences from Zircon U-Pb and Molybdenite Re-Os Dating Geoscience    2016, 30 (1): 59-68.   Abstract （12456）      PDF（pc） （3735KB）（17178）       Knowledge map    Save  The Wangwu Mo-Cu deposit is one that has been explorating and has the potential of large or super-large scale in recent years in North Wuyi region. Based on the study of geological feature, with LA-ICP-MS zircon U-Pb dating, the granophyre vein weighted mean age is (127.5±1.8) Ma(MSWD=1.4).It is shown that the deposit formed in Early Cretaceous Epoch. Using molybdenite Re-Os dating, the isochron age is (153.7±3.2) Ma(MSWD=3.9). It indicates that metallogenesis of Mo occurred in Late Jurassic Epoch. The diagenesis age of granophyre vein is much later than that of Mo deposit, which shows that there is no relationship between them. Comparing the neighbor deposit mineralization feature and analyzing the existed information, it infers that the rock of molybdenum is acidic granite porphyry or biotite granite, which is located in the deep area of southeastern part of the ore district. The major metallogenesis age of Mo is Early-Late Jurassic Epoch (155 Ma±) and Early Cretaceous Epoch(135 Ma±) in North Wuyi area. During this period, the formation of Mo and Cu deposits are related to magmation caused by paleopacific plate subducting. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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A Preliminary Discussion on Genesis and Ore-forming Fluid Characteristics of the Xinping Gold Deposit in Pingnan County, Guangxi,China Geoscience    2016, 30 (1): 29-35.   Abstract （10222）      PDF（pc） （3564KB）（17161）       Knowledge map    Save  The Xinping gold deposit is located in the Liucen ore field in Dayaoshan polymetallic mineralization belt. The ore bodies, hosted in the sandstone and mudstone of Cambrian Huangdongkou Formation, are related to the Xinping complicated anticline and fracture zone of EW-trending faults.Fluid inclusions in quartz suggest that ore-forming fluids are moderate temperature, low salinity, low density and contain CO2. The cations in fluids are Na+, Ca2+, Mg2+ and K+, while main anion is Cl-. The data of hydrogen and oxygen isotopes indicate that the ore-forming fluids are probably derived from magmatic fluids, and superimposed by metamorphic fluids and meteoric water also involved. The sulfur isotope values in sulfides are narrowly ranged negative not far from zero,which infers that sulfur in ore is a mixture of sulfur from deep source and strata. Our study combined with previous research show that Au has multisources, it mainly sourced from Cambrian strata, but the deep magmatic rocks in the region may also provide some Au. Based on above study, we conclude that the Xinping gold deposit was superimposed mineralization of metamorphism and magmatic-hydrothermal fluids. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Shale Gas Accumulation Condition and Resource Potential Analysis of Devonian in Dian-Qian-Gui Basin Geoscience    2016, 30 (1): 181-191.   Abstract （9664）      PDF（pc） （5146KB）（16967）       Knowledge map    Save Based on the outcrop observation, profile survey and sample analysis of Devonian dark shale, this paper studied the accumulation condition of Devonian shale gas in Dian-Qian-Gui Basin. The results show that two sets of dark shales of intraplatform depression facies were deposited in Dian-Qian-Gui Basin during the Early to Middle Devonian, and the single layer thickness of Devonian shale is 10-55 m; the accumulative thickness is generally between 100 m and 450 m. The TOC values are mainly in the range of 1.0% to 2.5%, and the organic matter type is Ⅰ-Ⅱ1, and the vitrinite reflectance values indicate high to over mature thermal evolution stages. As an effective reservoir, the porosity and permeability of Devonian shale in Dian-Qian-Gui Basin are similar to those of Jiulaodong Formation in well Wei-201, and various reservoir space types well developed in the shale, and the content of brittle minerals is averagely up to 67%. The gas preservation conditions of southwestern Qiannan Depression and middle-west Guizhong Depression are relatively better because of the relative flat strata, low fault density and erosion thickness, and thrusting and transpressional faults. Overall considering of the dark shale thickness, buried depth, organic matter content, thermal evolution degree and preservation condition, it can be predicted that the favorable intervals of Devonian shale gas are Tangding Formation and Luofu Formation, and the favorable areas mainly distribute in Tian’e-Nandan-Hechi area and Luzhai-Laibin-Heshan-Dahua area of middle Guizhong Depression. By using the analogy method of geological resource abundance, it can be calculated that the geological resources of Devonian shale gas is 0.66×1012 m3 to 1.09×1012 m3 . Related Articles | Metrics | Comments（0）

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Geology and S-, Pb-isotopic Geochemistry of the Jiashi Sandstone-type Copper Deposit, Xinjiang, China WANG Si-Cheng,XUE Chun-Ji,LI Zhi-Dan Geoscience    2011, 25 (2): 219-227.   Abstract （14827）      PDF（pc） （12457KB）（16872）       Knowledge map    Save The Jiashi copper deposit, located in Cenozoic piedmont basin system of southwestern Tianshan in Xinjiang, is an important sandstone-type copper deposit which has been discovered and mined recently.The ore bodies are tabular or stratiform in shape and occur in Neogene lightgrey detritusbearing calc-sandstone.The sulfide minerals in the ores are mainly chalcocite, fewer pyrite and sphalerite.Bornites occur at the deep part of the ore bodies.The ore shows disseminated, lumpish and nodular structures, and the sulfide minerals replaced the cemented calcites in the sandstone and formed a cemented texture.The ore δ34S V-CDT varies from -33.4‰ to -24.6‰.The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb of ore sulfide vary from 18.376 to 18.607, 15.612 to 15.655 and 38.475 to 38.747, respectively.It is suggested that the Jiashi copper mineralization was a replacement of the sandstone by copperbearing basin fluid (underground water).The ore bodies formed during late diagenetic stage of the sandstone in Paleogene.The ore sulfur was derived from sulfate reduced by bacteria and the composition of the Pb isotope indicates that the metal were originated from the erosion source area around the sedimentary basin. Reference | Related Articles | Metrics | Comments（0）

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Deep Structure beneath the Cenozoic Volcanic Zone in the Northern Qinghai-Tibet Plateau and Its Cause of Formation Discussion ZHENG Hong-wei, LI Ting-dong, GAO Rui, HE Ri-Zheng Geoscience    2010, 24 (1): 131-139.   Abstract （22843）      PDF（pc） （11994KB）（16716）       Knowledge map    Save There are a lot of Cenozoic potassic and ultrapotassic lavas in the northern Qinghai-Tibet Plateau, their existing is an enigma.We have collected all the available arrival time data recorded by the temporary seismic stations and phase reports from the International Seismological Center in Tibet and its surrounding areas.In the tomographic inversion, we have used 139,021 P-wave arrival times from 9,649 teleseismic events recorded by 305 seismic stations.Tomographic images show that the frontier of the lithospheric mantle of Indian plate （ILM） subducted beneath the center of Qiangtang terrane, and there is a great scale vertical low-velocity zone from deep to surface at the frontier of ILM.It supplies a channel for deep mantle upwelling.Hot materials of deep asthenospheric mantle might flow upward along the channel，then potassic and ultrapotassic lavas erupted in the northern Tibet.Cenozoic potassic and ultrapotassic lavas in the north Tibet are the direct result of northward subducting of ILM. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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3D Metallogenic Prediction Based on Minerogenetic Series: A Case Study in Tongling Mineral District of Anhui Geoscience    2016, 30 (1): 230-238.   Abstract （12037）      PDF（pc） （11334KB）（16675）       Knowledge map    Save In order to quantitatively predict the underlying mineral resources in Tongling mineral district and implement mixed genesis prediction according to the different deposit types, 3D metallogenic prediction based on minerogenic series is imperative. In this paper, we summarized two minerogenic series on the basis of previous studies, including the minerogenic series related to the Yanshanian magmatism and the sedimentary-reformation(metamorphic) minerogenic series. In addition, we summarized the porphyry-skarn-hydrothermal metallogenic model in the study area. Using 3D visualization technology, the 3D digital mine is modeled. After that,by implementing “cubic predicting model”prospecting method, we carried out a three-dimensional metallogenic prediction in the study area, and delineated 14 predicted targets according to the value of information and geolo-gical condition. Our research combines the traditional two-dimensional regional metallogenic prediction methods with advanced visualization technologies successfully, and extends the prediction of mineral resources within the region to three-dimensional space, makes it more conducive to concealed ore delineation work within the region, and also provides a reference for future three-dimensional prediction. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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3D Seismic Chimney Detection Technology Based on Dip Steering and Its Application on Buir Sag of Hailar Basin YANG Rui-zhao，LI Yang，PANG Hai-ling，ZHAO Zheng-guang，WEN Xiao-long， Geoscience    2013, 27 (1): 223-230.   Abstract （15558）      PDF（pc） （10940KB）（16593）       Knowledge map    Save The gas chimney is a special associated structure formed by the hot fluid flow in the sedimentary basin. As a specific channel for oil and gas migration, the gas chimney is a direct evidence for the existence of shallow reservoirs, and it can also influence hydrocarbon accumulation. These days, many scholars have paid attention to gas chimneys. Based on the research results and thoughts about gas chimneys home and abroad, through the artificial neural network (ANN) which is based on multi-layer perceptron and provided by the brand new seismic solution, i.e.OpendTect, this paper predicts the probability of occurrence for gas chimney, improves the algorithm by using dip steering, presents and applies seismic chimney detection technology based on dip steering. The application of pattern recognition technology in seismic exploration field has been well supplemented and developed. Generally, the 3D seismic chimney detection technology can not only interpret the migration pathway and reason of shallow gas accumulation, but also forecast the development of source rocks. In addition, it is also applicable for distinguishing fault sealing. At last, this process was applied to research the migration pathway and accumulation rules of an oil-bearing block in Buir Sag of Hailar Basin, and the fracture characteristics and types of migration pathways were put forward, then the special configuration relations of oil source, pathway, reservoir and cap rock were summarized, and the corresponding accumulation mode was  established. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Fracture Characteristics and Main Controlling Factors of Shales of the Second Member of Kongdian Formation in Cangdong Sag, Huanghua Depression Geoscience    2016, 30 (1): 144-154.   Abstract （9866）      PDF（pc） （7253KB）（16407）       Knowledge map    Save The shale in the second member of Kongdian Formation(Ek2) in Cangdong Sag with large thickness, high values and excellent types of organic abundance, is one of the important intervals for dense petroleum exploration. Based on the detail observation and description of cores, this paper studied lithologic characteristics, fracture types and development characteristics(including length, opening,angle and filling)of shales in Ek2 in Cangdong Sag of Huanghua Depression by the observation of polarizing microscope and fluorescence microscope and laser scanning confocal microscope together with analysis of X-ray diffraction and rock pyrolysis. Furthermore, it analyzed the main controlling factors of fracture development. The shales of Ek2 in Cangdong Sag are mainly composed of felsic, carbonate and clay minerals; the main lithologies are dolomitic shale, silty mudstone, argillaceous dolostone, sandy dolomite and dolomite, etc; the main types of sedimentary structures include massive structure, lamellar structure, laminated structure and lenticular structure, etc.Four sorts of fractures develop in Ek2, i.e. structural fracture, interlayer lamellation crack, vertical-difference load fracture and overpressure-breaking fracture, among which the structural fracture is the most, followed by the interlayer lamellation crack and vertical-difference load fracture, and the overpressure-breaking fracture is the least. The main fillings in fractures are pyrite, analcime, calcite and asphalt. The results show that tectonism, lithology, mineral composition, sedimentary structure, diagenesis and organic matter abundance(TOC) are the main controlling factors for the development of fractures in shales of Ek2 in Cangdong Sag. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Controlling Factors on the Miocene Channel in Baiyun Sag, Pearl River Mouth Basin Geoscience    2016, 30 (1): 200-208.   Abstract （9512）      PDF（pc） （6258KB）（16119）       Knowledge map    Save During 21-18.5 Ma, 13.8-12.5 Ma and 10.5-8.5 Ma of Miocene, the channels developed in Baiyun Sag. In these three stages, the shape and architecture of the channels were different. During 21-18.5 Ma, the architecture of the channel was simple, the channel extended a long distance and the sediment was deposited in the distal end. In 13.8-12.5 Ma, the channel migrated northward. During the early of 13.8-12.5 Ma, the channel only developed in the south, then developed upstream. The channel in 10.5-8.5 Ma became deeper and narrower, and had the convergent feature. These changes of these channels’ migration and shape feature were due to different controlling factors in these stages. In 21-18.5 Ma, the channel was related to the abundant sediment supply from the shelf margin delta. In 13.8-12.5 Ma, the channel was affected by the significant sea-level decline in 13.8 Ma. In 10.5-8.5 Ma, Dongsha Movement led to the Baiyun Sag uplift and the paleo-topography determined the channel development. The analysis of the controlling factors in different stages provided new information to the research of the channel shape and evolution in each stage. Related Articles | Metrics | Comments（0）

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Simulation of Secondary Hydrocarbon Migration Direction and Prediction of Favorable Zones：An Example from the Second Member of Shahejie Formation of West Slope, Shulu Sag Geoscience    2016, 30 (1): 220-229.   Abstract （9525）      PDF（pc） （1221KB）（16114）       Knowledge map    Save The Shulu sag in the south of Jizhong depression is a typical rift basin. Paleogene formation develops many sets of source-reservoir-cap assemblage, showing good exploration prospects. In order to seek the breakthrough in oil and gas exploration and to clarify the main exploration direction and zones, it’s urgent to deepen the understanding of the secondary hydrocarbon migration of the study area.Taking the Second Member of Shahejie Formation as an example, based on the Arcgis software platform, we could manage the various geological information, such as source kitchen, conducting system, structural features, fluid potential, etc. After then, we simulate the direction of the secondary hydrocarbon migration with fluid potential model under the large scale conditions. The simulation results reveal that the secondary hydrocarbon migration is dominated by nose-structural belt under the restraint of development status of sandbody, and the oil and gas gather in its spine. Finally, four nose-structural belts are selected to be the favorable accumulation zones based on the understanding of simulation results and reservoirforming conditions. Related Articles | Metrics | Comments（0）

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Engineering Treatment Effect Evaluation of Large-scale Wading Landslides in Badong County of the Three Gorges Reservoir Area Geoscience    2016, 30 (3): 695-704.   Abstract （9228）      PDF（pc） （3677KB）（16084）       Knowledge map    Save Engineering treatment effect of large-scale wading landslides in the Three Gorges Reservoir area has become a key issue that whether the reservoir can be in long-term normal operation. Taking the 15 large-scale wading landslides that have been treated in Badong County as the research object, this study summarized the large-scale wading landslides prevention and control engineering measures and analyzed the technical characteristics of large-scale wading landslide disaster prevention projects, and revealed that the anti-slide pile, slope protection engineering and drainage engineering have the highest utilization rate of engineering measures,and then pointed out the macro-deformation problems of engineering treatment based on the actual investigation.Combined with quantitative and qualitative evaluation method, this paper proposes an assessment approach with multi-levels and multi-factors. The index system was established according to the engineering treatment processes, survey results and the important factors that might change in the late operation. And based on the comprehensive evaluation value an evaluation standard was set up.The application case of XL01 landslide shows that this approach is practical and effective.Finally, this paper classified the large-scale wading landslides engineering treatment effect of Badong County according to the evaluation system. It comes to the conclusion that the engineering treatment has a good effect,but  there still have some problems. Related Articles | Metrics | Comments（0）

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Prospecting Model Based on Ground Hyperspectral Remote Sensing Data of Hongshan Cu-Au Ore Deposit in Xinjiang Geoscience    2016, 30 (3): 577-586.   Abstract （9198）      PDF（pc） （8568KB）（16067）       Knowledge map    Save Using FieldSpec Pro FR ground spectroscopy of American ASD Company, the authors carried out ground spectrum measurement for different geological bodies such as dacite,altered dacite,granite,granodiorite,rhyolite porphyry, schistosity belt and ore body respectively in the Hongshan Cu-Au deposit.The spectrum curves of geological bodies were achieved; and then the characteristics of absorption peak of spectrum and altered minerals were generally analyzed. According to the analysis results of microscopic identification and X-ray diffraction, this paper summarized the hyperspectral distribution characteristics of altered minerals and the mineral assemblage which are distributed in ore body, mineralized body, wall rock near ore body, altered wall rock and non-altered wall rock in the Hongshan Cu ore deposit. Based on the characteristics of mineral geology and ground wall rock alteration, the hyperspectral map of altered mineral assemblage formed and the prospecting model based on ground hyperspectral remote sensing data were constructed. The research provides hyperspectral data and typical deposit model for the further aerial survey, information extraction of altered minerals, and prediction for ore deposits. Related Articles | Metrics | Comments（0）

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Hydrogeochemical Characteristics and Evolution Laws of Groundwater in Haiyuan Basin, Ningxia CHEN Li，ZHANG Fa-wang，CHENG Yan-pei，LIN Wen-jing，CHEN Jiang，ZHANG Lin Geoscience    2009, 23 (1): 9-14.   Abstract （23534）      PDF（pc） （4379KB）（15988）       Knowledge map    Save Based on the hydrochemical and isotopic data, this paper analyzes the hydrological geochemistry characteristics of Haiyuan basin combining with the existed geological and hydrogeological data of this area. As a whole, the chemical fields of local groundwater have the obvious zonation patterns from the recharge area to the runoff area,and to the discharge area, which are in conformity with the evolution law of water quality in arid basin. Geochemistry simulation shows that the local water-rock interaction changes gradually from the dissolution-mixture action in the recharge area into the dissolutionevaporation action in the discharge area, chemical compositions of the Tertiary strata and the circulation condition have a great influence on the groundwater quality. Isotopic features show that the Nanhua Mountain-Xihua Mountain fault controls the groundwater recharge of Haiyuan basin, so far, there is little impact of exploitation on the quality of deep groundwater. In some sites, the improved water quality with the exploitation of groundwater was observed, one explanation for this is that the increasing velocity of local water shortens the water-rock interaction time.  Related Articles | Metrics | Comments（0） Cited: Baidu(13)

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Micro/Nano Pore Heterogeneity and Main Controlling Factors of the High-Maturity Longmaxi Formation Shale in Southeastern Chongqing Geoscience    2016, 30 (1): 163-171.   Abstract （10036）      PDF（pc） （2498KB）（15940）       Knowledge map    Save Studying shale pores is the key to understand the mechanism of shale gas occurrence and accumulation. But there is little effective means to quantitatively depict micro/nano pore heterogeneity characteristics of high-maturity shales. This article quantitatively analyzed micro/nano pore heterogeneity and main controlling factors of the high-maturity Longmaxi Formation Shale in southeastern Chongqing through the low pressure N2 adsorption/desorption, high-pressure mercury injection (MIP), and field emission scanning electron microscopy (FE-SEM) experiment together with the use of the fractal dimension. The results show that micro/nano pores develop very well in high-maturity shale. Mesopores are mainly slit-shaped clay interparticle pores and ink-bottle-shaped organic pores. Fractal dimensions of pores between 2.0 nm and 4.5 nm in diameter have an average value of 2.853,4, while fractal dimensions of pores between 4.5 nm and 50.0 nm in diameter have an average value of 2.736,7. The strong heterogeneity is mainly controlled by organic matters. When total organic carbon (TOC) content is less than 0.9%, the pores provided by minerals play dominant role, while the TOC content is larger than 1.7%, organic pores play dominant role. In addition, the increase of clay mineral content will increase the mesopores heterogeneity in a certain extent. Macropores are mainly composed of slit-shaped interparticle pores and a small amount of ink-bottle-shaped organic pores. Fractal dimensions of macropores have an average value of 2.844,1, which show strong heterogeneity, indicating the pore structure is complex. The heterogeneity of macropores is mainly controlled by quartz and carbonate minerals. With the increase of carbonate minerals content, the degree of heterogeneity increases. As organic pores size is relatively small, they have no obvious influence on shale macropore heterogeneity. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Alteration and Mineralization of the Guihuachong Porphyry Copper Deposit,Tongling Area, Anhui Province Geoscience    2016, 30 (1): 50-58.   Abstract （9890）      PDF（pc） （4665KB）（15925）       Knowledge map    Save Guihuachong copper deposit is a porphyry copper deposit newly discovered in the Tongling area, Anhui Province. Lithology of host intrusion is granodiorite porphyry, belonging to metaluminous high potassium calc-alkali granite. Wall rock alteration and mineralization study is an important porphyry deposit mineralization study on migration conducted alteration zone rock for geochemical composition of elements, which is based on the analysis of hydrothermal alteration processes. Wall rock alteration is strong in the Guihuachong mining area, and mainly consists of potassic alteration, sericitization, silicification, chloritization, and carbonatization. Alteration zoning is obvious, occurring potassic alteration, sericitization-silicification, and argillation-propylitization belts in outward succession. Major orebodies occur in the sericitization-silicification belt. Alteration and mineralization process of the hydrothermal stage from early to late is divided into four stages, i.e., potassic alteration, sericitization-silicification, quartz-polymetallic sulfide and carbonate stages. Mineralization took place mainly in the quartz-chalcopyrite sulfide stage. The results of migration quality of components in different alteration zones showed that variation of migration quality in the alteration process is high for the major elements except TiO2, MnO, MgO and low for the trace elements except Cr and Cu, and rare earth elements are loss in strong mineralization area and enrichment in the zone of mineralization.low for the rare earth elements. The similar chondrite-normalized REE patterns of the intrusion and the altered rocks from the Guihuachong deposit show close connection of the intrusion with mineralization of the deposit and it is the result of continuous action of magmatic fluids. Related Articles | Metrics | Comments（0）

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Hydrocarbon Accumulation Characteristics of Reservoir in Fula Depression and Their Implication for Petroleum Exploration, Muglad Basin, Sudan HE Bi-Zhu, WANG Wang-Quan, LV Yan-Cang Geoscience    2010, 24 (4): 709-718.   Abstract （7785）      PDF（pc） （13357KB）（15918）       Knowledge map    Save Before the discovery of Fula oilfield, previous studies consider that there developed source rock of semi-deep to deep lacustrine in Abu Gabra Formation,Fula depression,which were comprehensively evaluated to be good to very good source rocks but with lower thermal evolution degree, and the other main factors controlling the formation of oil pools were uncertainty, so Fula depression were considered lack of the oil and gas exploration potential. Based on detailed study of gravity data, seismic data and well data, analysis stratigraphic sequence, structure development and evolution, sedimentary facies combined with lithofacies, log-facies and seismic facies, this study reveals that the development of structure and deposition in Fula depression were controlled by shear-extensional regional tectonism. There developed a certain and effective hydrocarbon generation sag of the Abu Gabra Formation in Lower Cretaceous. Three favorable sourcereservoirseal assemblages and 4 reservoirforming zones are identified. The rollover anticline-faulted nose zone in the middle structure belt, the faulted noses zones in west margin of south sub-depression, in the south faulted step belt and in east margin of the north subdepression are evaluated prospect reservoir plays. Fula 1 rollover anticline and Fula 2 faulted nose are regarded as the best of prospect targets. These study results play an important role on oil and gas exploration and development in Fula depression. This research methods and exploration strategy can provide references for early petroleum exploration and basin analysis. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Main Uranium Mineralization Types and Their Comparison of Geochemical Characteristics in Xiangshan Orefield, Jiangxi Geoscience    2016, 30 (1): 1-16.   Abstract （9840）      PDF（pc） （7803KB）（15906）       Knowledge map    Save Nearly 30 uranium deposits found in Xiangshan orefield of Jiangxi Province, whose uranium mineralization are closely related to hypabyssal or super hypabyssal intrusive rock (subvolcanic rock). Whether porphyry or volcanic rock type is hydrothermal uranium deposits. Analyzing from the metallogenic tectonic characteristics of the hydrothermal deposits in the orefield, there are two kinds of uranium mineralization, namely, cryptoexplosion clastic rock type and alteration rock type, the latter mainly includes hydromica altered rock type and albitization altered rock type. In this paper, by collecting data, combining with the data of relevant topics, a comparative study of geochemical characteristics of various uranium mineralization was carried out. Results show that, the ore grade of cryptoexplosion clastic rock type is higher, and mostly content of U is more than 1%. There is lower SiO2 and Na2O and higher P2O5 , and the ratio of K2O and Na2O is 11.51 on average, and the main associated elements are Hf, Sb, Cu, Pb, Zn, Zr, etc.; K2O/Na2O of hydromica altered rock type is 4.83 on average, and associated elements are W, Pb, Mo, Th, Sb, etc.; K2O/Na2O of albitization altered rock type is 0.19 on average, U has a close relationship with CaO and P2O5, and associated elements are Sr, Zr and Hf, Sc, W, etc. From the albitization altered rock type, to hydromica altered rock type, to the cryptoexplosion clastic rock type, with the increasing of U grade, REE distribution curve appears a regular change from right to left lean. Related Articles | Metrics | Comments（0） Cited: Baidu(2)