2015 Vol. 21, No. 1

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TRANSMAGMATIC FLUID THEORY AND OREFIELD STRUCTURE
HEI Hui-xin, LUO Zhao-hua, Vikentyev I V, GUO Jing
2015, (1): 1-12.
Abstract (167) HTML (105) PDF (949KB)(19)
Abstract:
A new understanding of the ore-field structure is proposed. According to the theory of metallogeny by transmagmatic fluid (TMF), it is emphasized that the ore-field structure system is a complexity dynamic system. Based on this model, the ore-field structure deformation is resulted by strong interactions between the near-field and the far-field stress fields. The near-field stress field is induced by the magmatic mineral system instead of the far-field stress field. Accordingly, the regional structure can not be inversed by the ore-field structures, but it could constrain them. The ore-field fractures are often filled by magmatic and/or hydrothermal veins or veinlets, and hence can be recognized. Using the statistic method described in the structure geology, the density map (or contour map) of the magmatic and/or hydrothermal dikes can be used for prognosis of the prospecting targets.
THE WALL ROCK ALTERATION AND ITS GEOCHEMICAL CHARACTERISTICS OF ZHAOPING FAULT ZONE IN JIAODONG
ZHANG Zhi-hang, HU Bao-qun, WANG Xi, SHEN Yu-ke, GUO Tao, LÜ Gu-xian
2015, 21(1): 13-20.
Abstract (124) HTML (48) PDF (976KB)(22)
Abstract:
Zhao-Ping fault belt is an important gold metallogenic belt in Jiaodong area, and lots of altered-rock-types and quartz-vein-type gold deposits output in the belt and secondary faults of the footwall. To explore the geochemical features of the wall rock alteration, the Potouqing fault in Zhao-ping fault belt is taken as the research object, with the profile measuring and sample analyzing. It's showed that the alteration zones of the Potouqing fault are evident in Zhaoping fault belt. With the different alteration intensities in altered rock, the major elements' migration regularity is obvious. The enrichment of HREE is showed in the REE distribution curve. Eu and Ce have obviously negative anomaly. With the process from weak alteration to strong alteration, theΣREE, LREE and HREE significantly decrease, and the regular changes are showed by the corresponding characteristic value, Au-Ag-Bi-Co-Cu-Mo-Ni-Pb-Zn is the indicator element suite which is closely related to the gold mineralization.
APPLICATION OF IN-SITU MEASURED SPECTRA DATA BY ASD FieldSpec3 ON LITHOLOGIC CLASSIFICATION IN SHUIMO-DAHE AREA
HE Yang, XU Tao, SONG Yun
2015, 21(1): 21-29, 72.
Abstract (150) HTML (51) PDF (1815KB)(11)
Abstract:
This paper chose the Shuimo-Dahe area of Sichuan Wangcang as its research area, use ASTER image and in-situ measured spectra data by ASD FieldSpec3 as the research object, extract mineral endmember information according to rock spectral curve from field survey data and USGS spectral library, match the spectral curve of image pixel, combine ENVI4.4 software for automatic information extraction and man-computer interactive interpretation, to conduct lithology classification, based on GIS, it has an important application value for basic geological survey and mineral survey.
DISTRIBUTION OF THE PRESENT STRESS IN LOW PERMEABILITY OILFIELD OF BOZHONG 25-1 AND ITS EFFECT ON DEVELOPMENT
LIAO Xin-wu, LIU Qi, LI Chao, ZU Ke-wei, ZHOU Jun-liang, HUANG Kai
2015, 21(1): 30-37.
Abstract (203) HTML (116) PDF (1095KB)(43)
Abstract:
Based on the finite element method, numerical simulation on the state of present stress in Bozhong 25-1 oilfield which is the first low permeability oilfield carried out to be developed by CNOOC is studied. Combined with the geological characteristics, the impact of the stress on development is analyzed. It is showed that the stresses in the second and the third member of Shahezi Formation are pressure stresses and the direction of the maximum principle stress is mainly NEE-SWW. The stress is controlled by fault, structural relief and sedimentary microfacies on the plane. According to the state of the stress, the artificial fractures are vertical fracture in this area; the direction of the stress is seriously deflected near the fault, which causes the deflection of the extension direction of artificial fractures. Therefore, some adjustments should be made near the fault based on the actual distribution of stress, when the development well patterns are arrangement.
NUMERICAL SIMULATION OF STRUCTURAL STRESS FIELD IN THE LATE SEDIMENTARY PERIOD OF Es4 AND PREDICTION OF THE LOWER-ORDER FAULTS IN LANGGU SAG
ZHANG Dan-dan, DAI Jun-sheng, FU Xiao-long
2015, (1): 38-46.
Abstract (185) HTML (79) PDF (1148KB)(8)
Abstract:
On the basis of the research of structural background, fault activity and structural evolution, the method of numerical simulation of structural stress was applied to simulate the stress distribution in the late sedimentary period of Es4 in Langgu sag, and the development of the lower-order faults could be predicted. The research showed that the active faults in the late sedimentary period of Es4 were Daxing fault, Banjiehe fault and so on. Niubei slope belt and Hexiwu structural belt were uplift obviously during this period. The comprehensive analysis indicated that the direction of the minimum principal stress was SE144°-NW324°, the development of the lower-order faults were mainly influenced by the minimum principal stress and the shear stress, et al. The minimum principal stress and the difference between principal stresses (the maximum and minimum principal stress) controlled the advantage area of the fault development. The plane shear stress controlled the fault strike, and its most faults in this area were NNE-NE. The profile shear stress controlled the dip direction, in the main part of this area the profile shear stress was sinistral shear stress, which showed that the dip direction of the most faults was NW.
NUMERICAL SIMULATION OF STRUCTURAL FRACTURES CONTROLLED BY REVERSE FAULT
GAO Xiao-qiao, ZHANG Da
2015, 21(1): 47-55.
Abstract (155) HTML (83) PDF (1046KB)(17)
Abstract:
Based on the research on development of structural fractures that controlled by reverse fault, this study has simulated the distribution of the stress, strain and the development rules of fractures under the different conditions of horizontal forces, lithological characters, fault dip and the different distances to fault location in the fault zone by using COMSOL finite element software. It is shown by the simulation results that the development degree of structure fractures increases linearly with the increase of horizontal forces. The strain generated before rock failure can be used to describe the brittle properties of rock. Compressive strength is the main factor that makes rocks rupture and the shear strength of rock has relationship with the development of rock fracture. There is a critical angle in reverse fault dip and it can make the fracture strongest developed. The fracture density decreases as the distance from the reverse fault increases and there is a damage region controlled by reverse fault where the fracture density decreases sharply. This region is closely related to the mechanics, scale, displacement of the reverse fault and rock mechanics parameters.
THRUST\STRIKE-SLIP-FAULT BELT STRUCTURES EVOLUTION CHARACTERISTICS AND PHYSICAL MODELING OF ZAIRE MOUNTAIN
WANG He-hua, WU Kong-you, PEI Yang-wen, GUO Wen-jiang, LIU Bo
2015, 21(1): 56-65.
Abstract (242) HTML (131) PDF (1347KB)(21)
Abstract:
As the exploration direction transfers to orogenic belt in the northwestern margin of Junggar Basin, the thrust belt of Zaire Mountain has become the exploration focus. Previously, the thrust belt is thought to be typical over-thrust and nappe belt, but the fault space composition relationships on the seismic sections show thrust\strike-slip-fault belt characteristics. The whole system of thrust\strike-slip-fault belt can be divided into two stages. The first stage is thrust-nappe during Carboniferous to Permian, and the second stage is thrust-torsion strike-slip during Triassic to Jurassic. In the physical simulation experiment, the characteristics and style changes of strata and fault in the two stages above are simulated, and it is confirmed that the thrust\strike-slip system really exists. Summarizing the development rules, we induce "chuan" word style on the plane and "from" word model in profile. The establishment of geological model provides a new direction for understanding the whole northwestern margin structure system. At the same time, it plays an important role in seismic interpretation and well location selection, and it also provides guidance for further exploration.
RESEARCH ON CORE FRACTURES: A CASE STUDY FROM THE FUTAI OILFIELD
ZOU Juan, DAI Jun-sheng, SHANG Lin, TIAN Bo
2015, (1): 66-72.
Abstract (203) HTML (87) PDF (1007KB)(15)
Abstract:
Through core observation in Futai oilfield, we describe the geometric characteristics, filling characteristics and mechanical properties to conduct research on various parameters of fractures. The results showed that a great amount of structural fractures was developed in Futai buried hills, which formed two directions. One was NE-SW and NW-SE direction conjugated shear fractures that were dominant, another was nearly E-W. Fractures were mainly vertical ones with the characteristics of E-W shear fractures. The core fracture openings which were mainly half filled with calcite were mainly distributed in 0.6~0.8 mm. Its average volume density was between 5~10 m2/m3, and fractures developed much more in northern part than southern of Futai oilfield.
RESEARCH ON THE ENGINEERING GEOLOGY CONDITION AND RAILWAY ROUTES COMPARISON ALONG THE Mt. GAOLIGONG SECTION, DALI-RUILI RAILWAY
LI Guang-wei, DU Yu-ben, JIANG Liang-wen, GUO Chang-bao, SHEN Wei, LIU Xiao-yi
2015, (1): 73-86.
Abstract (151) HTML (121) PDF (1327KB)(19)
Abstract:
Based on the field geological investigation, drilling, in-situ stress measurement and lab test analysis, this paper illustrates the main engineering geological problems that could be encountered in the Mt. Gaoligong section railway planning and construction, such as high geo-temperature, high geo-stress, active fracture dislocation, rock burst, water pouring out and mud squirting, large deformation of the soft rock, landslide, and so on. The paper deems that the high geo-temperature and thermal harm are the key factors restricting the Mt. Gaoligong deep-buried tunnel section. According to geothermal drilling and lad test results analysis, the geothermal distribution is obviously controlled by the geology structure, and the Huangcaoba fault has the engineering geology of block water and heat insulation. Based on comprehensive comparative analysis, the C12K scheme (34.6 km long tunnel scheme) is a better scheme, located in the relatively low geothermal channel, south of the Huangcaoba fault, and this scheme has avoided some unfavorable engineering geological problems such as the ancient landslide at the tunnel entrance. The survey and research results have great importance for the landslide optimization and further design.
ANALYSIS ON MAIN CHARACTERISTICS OF EARTHQUAKE DAMAGE CAUSED BY MS 6.1 EARTHQUAKE ON MAY 30, 2014 IN YINGJIANG COUNTY, YUNNAN PROVINCE
WU Kun-gang, WU Zhong-hai, HUANG Xiao-long, FENG Hui, ZHOU Chun-jing
2015, (1): 87-96.
Abstract (105) HTML (77) PDF (1214KB)(9)
Abstract:
The Ms 6.1 earthquake occurred in Dehong Dai and Jingpo autonomous prefecture in Yunnan province on May 30 nine twenty, a large number of civil building destruction. This paper comprehensively analyzes the characteristics of building damage caused by the earthquake and the main secondary geological disasters by the means of on-the-spot investigation and visit. At the same time, this paper preliminarily summarizes their causes and all kinds of damage characteristics of building caused by earthquake and the characteristics of main geological disasters. The results show that in the southwest mountainous earthquake prone area which is similar to Yingjiang, the urban constructions not only need to choose high strength building materials and ensure architecture qualifications, but also pay close attention to scientific location, try to avoid the earthquake and geological disasters prone zone such as the landslide, collapse, debris flow and others. To minimize the potential earthquake damage, poor stability field should be reinforced by means of some necessary foundation treatments engineering. The geological disasters are likely to occur around the road should also take proper reinforcements to avoid the earthquake causing traffic gridlock, and greater loss of life and property.
ANALYSIS ON DEVELOPMENT CHARACTERISTICS AND FACTORS OF GEOLOGICAL DISASTERS IN YANJIN COUNTY, YUNNAN PROVINCE
XIANG Xiao-long, SUN Wei-feng, LI Guo-wei, HOU Chun-tang, TAN Cheng-xuan
2015, (1): 97-107.
Abstract (284) HTML (107) PDF (1032KB)(26)
Abstract:
The geological disasters in Yanjin County in Yunnan Province are a big threat to the local people's safety and society development. By analysis on the geology data, combined with field work, we find that landslide occurs in the quaternary loose soil sediments. Collapse occurs in the slope where it consists of sandstone, shale, mudstone, and could be appeared in the high slope in the limestone area, debris flow and other landslide disasters related to earthquake, raining and human engineering activity and mining activity. The main controlling factors are geological structure, topography, slope structure and engineering geology rock group; the main inducing factors are earthquake activity, rainfall, and human engineering activity. Accurate analysis of the geological disasters factors will contribute to the work of disaster prevention and reduction.
STUDY ON THE STABILITY OF HIGH SLOPE OF THE MINJIANG RIVER DOUBLE-TRACK BRIDGE
CHEN Hang, QIU Min, PENG Ya-ting, LONG Xue-mei, ZOU Zu-yin
2015, (1): 108-116.
Abstract (159) HTML (75) PDF (1031KB)(11)
Abstract:
The high slope of Double-track Bridge on Minjiang River of Chenglan Railway is located in Minjiang River seismic belt, which is a high and frequent seismic region, with substantial concentrated rainfall and widespread unfavorable geology. Under the impact of the complicated environmental factor, it may give rise to the slope slide easily. In this paper, 3D slope mode is established with FLAC3D finite difference software based on the study on the geology of field engineering, and stability analysis in such working conditions as the natural rainfall, earthquake and coupling of rainfall and earthquake. According to the results, the safety coefficient in natural working condition is 1.318, and the slope is in stable status. In rainfall working condition, with the increase of rainfall, the rainwater infiltration and loading function is enhanced, and the displacement high-value area expands gradually and extends to the slope toe. In 25 mm/d, 35 mm/d and 45 mm/d rainfall condition, the safety coefficient is 1.001, 0.932 and 0.912 respectively. The slope is quite unstable in earthquake working condition, and the upside displacement and accelerated speed of the mid-slope is the greatest, and it is easy-sliding area. In the coupling working condition of rainfall and earthquake, the upside of mid-slope is extremely unstable, and with the increase of rainfall, the displacement and accelerated speed would increase.