2008 Vol. 14, No. 3

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2008, 14(3): 1-1.
Abstract (74) HTML (57) PDF (74KB)(6)
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COULOMB STRESS CHANGES CAUSED BY WENCHUAN EARTHQUAKE AND ITS INFLUENCE ON SEISMIC ACTIVITY IN THE ADJACENT AREAS
WANG Lian-jie, ZHOU Chun-jing, SUN Dong-sheng, WU Zhen-han, WANG Wei
2008, 14(3): 193-200.
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On 12 May 2008, M8.0 Wenchuan earthquake occurred along the Longmenshan fault belt in Sichuan Province of China, causing enormous losses and thousands death, and the rearrangement of crustal stress commonly leads to damaging aftershocks.Coulomb stress changes caused by the Wenchuan earthquake are calculated and earthquake activity is evaluated using finite element method for some faults around the area.Results show that Coulomb stress displays a greater changes in northeast part of Longmeshan fault belt, including Beichuan, Qingchuan, Ningqiang areas and so on.Most of aftershocks of Wenchuan earthquake occurred in the area where the Coulomb stress change is increased. Coulomb stress gets weaker in most parts of Xianshueihe fault (b-1, b-2, b-4)except for some parts (b-3).It shows an increase to northwest of Chengdu, but a decrease to southeast of Chengdu.Coulomb stress increases can bring faults to failure, with delays ranging from seconds to decades.
STAGES OF THE NEOTECTONIC MOVEMENT OF THE MENYUAN BASIN IN THE MIDDLE SEGMENT OF THE QILIAN MOUNTAINS
MA Bao-qi, LI De-wen
2008, 14(3): 201-211.
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The Menyuan Basin is an intermontane basin in the central segment of the Qilian Mountains, bounded by boundary faults on the north and south.The basin is filled with the Paleogene Baiyanghe Formation and Quaternary tills and glaciofluvial deposits.The differences in rock deformation, geomorphological evolution and fault movement phases show that the Menyuan Basin underwent four stages of tectonic movements since the Cenozoic.The earliest Cenozoic tectonic movement began in the middle Oligocene (30 Ma B.P), when the I-order planation surface was disintegrated and basin was downfaulted and received sandy gravel deposits of the Baiyanghe Formation.The second stage occurred from the end of the Oligocene to the beginning of the Miocene (25 Ma to 460 ka B.P)and was characterized by the end of the basin subsidence, termination of Tertiary deposition and folding of the Baiyanghe Formation. This process continued to the initial middle Pleistocene.The third stage started in the middle part of the middle Pleistocene (460 ka B.P)and ended at 30 ka B.P.During the stage new boundary faults formed, the basin was again downfaulted and received >400 m thick tills and glaciofluvial deposits, and boundary faults were very active.This process lasted till the late part of the late Pleistocene (30 ka B.P).The latest stage began at 30 ka B.P, which was marked by the wholesale uplift of the basin and mountains at both sides of the basin and transition of the basin surface process from deposition to incision and erosion.The fault movement changed from thrusting with a strike-slip component to strike-slip movement, but the strike-slip rate decreased significantly.
GEOMATICS AND EARTH OBSERVATION SCIENCE (EOS) FOR DISASTER MANAGEMENT:AN OVERVIEW
LIU Yu-tao
2008, 14(3): 212-220.
Abstract (231) HTML (97) PDF (315KB)(8)
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Based on an introduction of disaster management, geomatics and earth observation science (EOS), a discussion has been made on the utility of geomatics and EOS for natural disaster management.It is believed that the development in new techniques on sensors, high-resolution satellite remote sensing system can provides multiple source, timely and accurate spatial data on disaster management can improve the accuracy of satellite image interpretation and strengthen the capability of natural disaster detection and identification.The development in SDI and related techniques, as well as the strengthening function of software, not only drives the ongoing improved data availability, accessibility and data sharing, enhances data management, processing, analysis and dissemination capability, but also improve the quality and visualization of disaster forecasting and decision-making, hence increase efficiency and effectiveness at all levels of disaster management activities.In addition, their limitations and potential research challenges in the current geomatics and EOS for disaster management have been generally discussed.
THE CONDITION AND PATTERN OF TURBIDITE FAN RESERVOIR FORMATION IN EASTERN DONGYING DEPRESSION, SHANDONG PROVINCE
SUN Hai-ning, XIA Jing-sheng, ZHONG Jian-hua, WANG Zhi-kun
2008, 14(3): 221-230.
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Abstract:
Lithologic hydrocarbon reservoir has been thought of a focal point of exploration in Dongying depression.A great amount of massive source rocks developed in Members 3 and 4 of the Shahejie Formation (S3 and S4) in eastern Dongying depression provide sufficient hydrocarbon resources for lithologic traps.In this area there are well developed fluxoturbidite in front of delta, deep-water turbidite fan and other little sand body, and such transportation systems as sand bodies, rifts, and unconformities, as well as mudstone seal, are often met with.There are good matching source rocks, reservoir bed and seal display a good match spatially and temporally, which provided a favourable conditions for formation of lithologic hydrocarbon reservoir and structure-lithologic hydrocarbon reservoir.
THE GEOMETRICAL CHARACTERISTICS AND FORMATION MECHANISM OF POLYGONAL FAULTS IN DEEP-WATER BASIN
WU Shi-guo, SUN Qi-liang, DONG Dong-dong
2008, 14(3): 231-240.
Abstract (212) HTML (85) PDF (812KB)(11)
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Polygonal fault system is a tensional fault system with small throws.Because of their polygonal shape on plan, they are named polygonal faults.They have been studied for more than ten years since they were defined in North Sea in 1994, and from then on, they have been recognized in more than fifty passive basins worldwide.Research on polygonal fault needs high-resolution 3D seismic data, so, until now no research on polygonal fault has been made in China.The mechanism of polygonal fault is the focus of preliminary studies.Many experts think that the volumetric contraction induced by syneresis during the early-stage compaction of fine sedimentation is the mechanism for the development of polygonal fault systems.Many polygonal faults formed in continental slope, so some scholars believe that gravitational spreading is the mechanism for the polygonal fault formation.Polygonal faults affect the attributes and distribution of deep-water hydrocarbon reservoir which provide pathway for fluid, so they are important for migration and accumulation of hydrocarbon and gas hydrate.
THE "MULTI-POSITION IN ONE" MODE AND DYNAMIC MECHANISM OF MINERALIZATION OF TUNGSTEN DEPOSITS IN JIANGXI
YANG Ming-gui, ZENG Zai-lin, LAI Zhi-jian, WU Xin-hua
2008, 14(3): 241-250.
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Taking the Zhangtiantang-Xihuashan tungsten band as an example, this paper proposes a "multi-position in one" mode for tungsten deposits based on lots of explorations for tungsten deposits in Jiangxi.The core of the mode is the structure-magma-metallogenic series with genetic relation, composed of different kinds of tungsten deposits and with metallogenetic granite as its main factor.It focuses on displaying the four-dimensional structure of vein-type tungsten deposits and rules on orientation as well as various modes of vertical zoning in deposits.Meanwhile, based on obserbation of the thermodynamic process of vein-type tungsten deposits, this mode reveals the alternation of zone-level extrusion and twist with induced part-vertical inner stress field, and cutting and fracture of rocks with their expanding and recharging.It also shows constraint of the process on the whole structure of tungsten deposits and their temporal and spatial distribution.
ANALYSIS ON THE KAIYATASI VOLCANIC APPARATUS AND ITS METALLOGENETIC POTENTIALITY IN GUOZHIGOU AREA OF THE WESTERN TIANSHAN, XINJIANG OF CHINA
ZENG Xiao-ping, MENG Hong, CAO Sheng-xiu
2008, 14(3): 251-262, 250.
Abstract (237) HTML (97) PDF (543KB)(4)
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The Early Carboniferous volcanic apparatus is an important metallogenetic structure for formation of gold deposit in the Western Tianshan.A study on the formation time of the volcanic apparatus, rock types, volcanic facies, eruptive cycles and metallogenetic conditions shows that the volcanic apparatus was formed about 331Ma ago, associated with calc-alkaline series rocks, and bearing volcanic cycle from explosive facies to extrusive facies and then to explosive facies.The volcanic rock has a higher background values of Sb, Pb, Mo, Bi, Au, So, constituting a good conditions for formation of the volcanogenic massive sulfide deposit.
CHARACTERISTICS OF MINERAL INCLUSIONS IN GRANITES CLOSELY RELATED WITH GOLD FORMING IN EASTERN SHANDONG PROVINCE
WANG Hai-qin, HUO Guang-hui
2008, 14(3): 263-273.
Abstract (273) HTML (119) PDF (393KB)(8)
Abstract:
In eastern Shandong Province (Jaodong area), there are distributed Linglong gneissic granite, Luanjiahe granite, Guojialing diorite and Shangzhuang monzonitic granite, which have close relation with Jiaodong gold mine.According to developing degree, type, size and characteristics of mineral inclusions, and based on temperature-measuring result by microscope, it is indicated that the Linglong rock mass was formed by remelting of granite caused by high regional metamorphism, the Guojialing rock mass was derived from crystallization of a high-temperature and high-viscosity magma, the Luanjiahe rock mass was crystallized from high-temperature, high-viscosity and CO2-rich magma at a relatively small depth, and the Shangzhuang rock mass was formed at a low-temperature and lowpressure condition.
ROCK RHEOLOGICAL MECHANICS: PRESENT STATE OF RESEARCH AND ITS DIRECTION OF DEVELOPMENT
ZHANG Yao, XIONG Liang-xiao
2008, 14(3): 274-285.
Abstract (414) HTML (156) PDF (336KB)(30)
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The development in the rock rheological test has been summarized from uniaxial rheological compression tests, multi-axial rheological compression tests, tensile fractural rheological tests, shear rheological tests of rock masses and structure planes and various influence factors in rheological tests.In addition, the development in the rock rheological model was reviewed from the empirical model, component model, damage and fracture model, endochronic theory-based rheological model and elastic visco-plasticiy model.Finally, several problems on the research are presented with respect to rock rheological mechanics in the future, such as rock nonlinear rheology with the complex stress path, hydromechanical-stress coupling effect and anisotropic effect.
MEASUREMENT OF ROCK STRESS OF HONGLING COAL MINE
ZHAO Wei-hua, SUN Dong-sheng, WANG Hong-cai, LIANG Jun-yi, WANG Ping, ZHANG Jun-hong, WANG Jun
2008, 14(3): 286-291.
Abstract (354) HTML (167) PDF (240KB)(4)
Abstract:
To get a knowledge of in-situ stress and its distribution in the Hongling coal mine, a measurement has been done for the rock stress in coal mine area by using hollow inclusion gauge method. In this paper, the results of rock stress measurement of 3 levels are introduced, the characteristics of stress distribution are discussed.The results show that the principal stress goes in nearly NNE direction and ranges in value from 18.32 to 21.5 MPa.The horizontal stress takes the dominating place and has a bigger value than the vertical one.The middle principal stress is nearly vertical and changes in value from 13.1 to 14.79 MPa. Value of the minimal principal stress is 9.54~13.08 MPa.The value of in-situ stress increased with depth.The measurement results can be applied to mine design.

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