1999 Vol. 5, No. 2

Display Method:
STUDY OF STABILITY OF YANGJIACAO SLIDE MASS IN THE GEHEYAN RESERVOIR ON QINGJIANG RIVER
XU Ruichun, XU Tongha
1999, 5(2): 2-10.
Abstract (157) PDF (281KB)(8)
Abstract:
A modern newly built town is found to be located on an old slide mass after the resettlement.The local government and the residents are much concerned about the stability of the town.So a detailed geological investigation has been carried out.The slide is dated as being of an age of 22 000-24 000a B P.An analysis of the sliding mechanism the canstitution and structure of the slide mass and the properties of the sliding zones brings to light that the old slide mass will be stable over a considerably long time.Moreover, a large cave system was revealed in the slide mass with on underground river which empties into the Qingjiang river forming a natural underground drainage conducive to reducing a landslide.Some countermeasures are suggested to be immediately taken to ease the anxiety of the local people to resume their normal life.
STUDY ON 3-D STRESS FIELD OF SHUIBUYA DAM SITE ON QINGJIANG RIVER
HU Daogong, SHI Ling, TAN Chenxuan, XU Ruichun, MEI Yingtang
1999, 5(2): 11-15.
Abstract (150) PDF (144KB)(6)
Abstract:
The Shuibuya hydroelectric project will be built in gorge morphology on Qingjang River, the gravitation is key factor which decides whether the rock in dam site is stable or not.In this paper, we study stress and strain field of rock body in dame site under the gravitative using 3-D finite-element simulation method, the result provides an important evidence for project construction and assessing the stability of rock slope.
ENGINEERING EVALUATION OF ACTIVITY OF JIANSHI FAULT IN WESTERN HUBEI PROVINCE
WANG Huabing, WU Shuren, YI Shunhua
1999, 5(2): 16-21.
Abstract (171) PDF (108KB)(10)
Abstract:
A detailed study of the fractal geometry deformation structure, as well as the latest and present tectonic activity of Jianshi fault has been made to bring to light the kinematic and dynamic characteristics of the fault and its evolution.It was a thrust fault in the main episode of the Yanshanian epoch, an extension fault in the late Yanshanian and a sinistral strike slip fault in the Himalayan.In the Neogene, the northern segment of the fault underwent a stronger dextral strike slip than its central and southern segments.In Q1-Q2 it was once active, and age of the latest activity is determined to be about 197.6±160 thousand years and is presently weak in seismicity.It is therefore concluded that the Jianshi fault is an in active fault, in the engineering sense, causing no essential harm to the nearby hydropower works.
RESEARCH ON WANGJIAWUCHANG LANDSLIDE IN THE NEWLY BUILT WUSHAN COUNTY,THE THREE-GORGES RESERVOIR REGION
ZHANG Jiagui
1999, 5(2): 22-29.
Abstract (197) PDF (179KB)(7)
Abstract:
The resettlement project is the key part of the Three Gorges Project on the Yangtze River.The geology of the new Wushan County site is the focus of current public concern a problem common in the Three-gorges Reservoir region.The geomorphology and structure of the slide mass is analysed in detail.The results reveal that the landslide has gone through two stages of development;in the earlier stage there having been repeated small slides, while in the later stage, restructuring of the slidemass becoming dominant. Karstification was well developed especially where the rocks were structurally fragmented, leading to undermining the mass from depth.Although the slidemass now remains relatively stable, precautions should be taken to prevent the mass from saturation.
THE ORIGIN AND MECHANIAM OF THE COUPLED TWISTING OF EARTH'S SPHERICAL LAYERS
ZHANG Yonghong
1999, 5(2): 30-39.
Abstract (98) PDF (246KB)(7)
Abstract:
The global torsion tectonic system does not only involve the surface but also the interior of the spherical Earth. This paper describes emphatically the mechanism of the coupling of twisting of the Earth's individual spherical layers, that controls the plate tectonics.
There is an inclination of 62°36' between the Earth's equator and the galactic equator. When the galactic center moves from the north to the south of celestial sphere, the plastic mantle of the Earth will migrate towards its southern hemisphere and the continental plate will drift to its northern hemisphere under the control of the centrifugal force of revolution. Such a process will lead to the asymmetry of southern and northern hemisphere and a twisting of the two hemispheres. So there is a correpondence between the rhythm of the Earth's continental drift and the cycle of spirals of the galaxy. In solar system planets (or satellites) which revolves in the same way as the Earth will undergo a synchronous twisting.
LATERAL SLIP OF MERIDIONAL STRUCTURAL BELTS IN CHINA
ZHAO Jianwei
1999, 5(2): 40-45.
Abstract (145) PDF (114KB)(6)
Abstract:
In the past, meridional structural belts in China were mostly described as purely compressional and tensional, but in recent years there have been found evidence to show they have undergone some lateral slip. In west China, they are mostly dextral, and in east China, they are dominantly sinistral. The overall result of such a gliding regime points to a southward movement of the China.
FRACTAL ANALYSIS OF MOUNTAIN RANGES AND FAULTS IN CHINA
ZHU Xiaohua
1999, 5(2): 46-51,71.
Abstract (250) PDF (135KB)(10)
Abstract:
A fractal and statistical analysis of mountain ranges and faults has been made respectively for southwest China and the whole continental area of China. It is found that the fractal dimension is 1.63 for mountain ridges in continental area of China, and 1.35 for those in southwest China. The fractal dimension is 1.65 for mountain ranges or faults indicates the difference of the frequency of distribution of mountain ridges or faults. The higher frequency of long mountain ranges or faults in southwest China than in the whole continental area of China, leads to the smaller fractal dimension of mountain ridges or faults in southwest China than in the whole continental area of China. It is concluded that both faults and mountain ridges are results of tectonic movements.
PRIMARY STUDY ON THE WESTERN GUANGDONG NAPPE ZONE IN THE HERCYNIAN AND INDOSINIAN EPOCH
ZHU Dagang, MENG Xiangang, PENG Shaomei, FENG Xiangyang, WANG Jianping
1999, 5(2): 52-59.
Abstract (139) PDF (151KB)(8)
Abstract:
The NE-NNE trending western Guangdong nappe zone extends along LuodingYunfu-Qingyuan-Yingde for 350 km, forming an arc bending towards the southeast.It was thrust from northwest to southeast with a distance of more than 40 km.The allochthon consists of the Presinian, Sinian and Cambrian system.The autochthon comprises the Devonian and Carboniferous system.It was mainly formed in the Hercynian and Indosinian epoch, and underwent strong tectonism movement, magmatism and sedimentation in the Yanshanian movement.Subsequent erosion caused the development of structural windows.It is a large strongly modified syn-collision nappe zone.
THE FRACTURES PATTERNS AND TECTONIC STRESS FIELDS IN SHANSHAN OIL FIELD, XINGJIANG
YUE Leping, ZHANG Li, WU Shiping, ZHU Yongxian
1999, 5(2): 60-65.
Abstract (225) PDF (71KB)(10)
Abstract:
Based on the investigation of field joints and cracks in the field paleomagnetic orientation of cracks in cores, and identification of cracks in dip logging curve, we have analyzed the tectonic stress field in Shanshan oil field.Xinjiang N30-40E-and N30-50 Wtrending conjugate shear fractures are well developed in the reservoir rocks.And high-angle, especially vertical fractures are predominant.
The structures in the Shanshan oil field were formed by a nearly N-S compression at the Yanshanian movement in Late Jurassic.The structures comprise the N-S-trending normal faults and the NE-NW conjugate fractures.
The present maximum horizontal principal stress determined from an analysis of the changes of the diameter of the drilling holes by dip logging is about 140° which is consistent with equivalent to the direction of fractures that would be artificially produced in the oil field.
GEOCHEMICAL FEATURES OF THE VOLCANIC ROCKS OF LINZIZONG GROUP IN CHUOQIN BASIN
SONG Quanyou
1999, 5(2): 66-71.
Abstract (156) PDF (218KB)(6)
Abstract:
Violent volcanic eruption occurred in the Chuoqin Basin of Qinghai-Tibetan Plateau during Cenozoic era, resulting in volcanic rocks consisting of andesite, rhyolite, intemediate-acid lava flow and pyroclastics known as the Linzizong Group which are distributed mainly in the Gangdise tectono-volcanic belt of the central uplift in the Chuoqin Basin but sparsely scattered in the north depression. Petrochemical study suggests the volcanics are of calc-alkalic to high potassium calc-alkalic suite; Geochemical study indicates that they are akin to the island are type formed by collision of the Himalayian plate with the Gangdis-Nianqing Tangula plate.
MECHANISM OF FORMATION OF DECOLLEMENT THRUST ZONE AND THE PROSPECT OF OIL-GAS IN KUCHE DEPRESSION IN NORTH TARIM BASIN
ZHOU Xingui, SUN Baoshan, LI Yuehui, SHAO Zaogang
1999, 5(2): 72-77.
Abstract (183) PDF (82KB)(20)
Abstract:
This paper describes detailedly the characteristics of decollement thrust zone both in plane and in section of Mesozoic-Cenozoic rocks in the Kuche depression in the south foreland North Tarim basin by an analysis of the geophysical and geological data available. A mechanism of the formation of the thrust zone is first put forward and is followed by a preliminary evaluation of the oil-gas resources. The fault bend folds behind the Qiulitake arc and the triangle zone and the salt domes in the front of the thrust stack are considered the likely oil traps.
A MIRROR IMAGE SYMMETRY HYPOTHESIS FOR THE METALLOSENY OF YIMEN COPPER DEPOSITS AND ITS SIGN IFICANCEIN IN MINERAL EXPLORATION
HAN Runsheng, SUN Jiacong, LI Jun, MA Dyun, LUI Wei
1999, 5(2): 78-83.
Abstract (246) PDF (274KB)(22)
Abstract:
Based on the correspondence of ore deposits (mineralization points) on the two opposite sides of a certain reference line (or plane) in the western of the Yimen copper ore field, the late Prof. Sun Jiacong had an idea of the mirror image symmetry of the ore distribution of the a tea. This is considered to have a bearing on prediction and exploration of mineral resources for the Yimen ore field and other similar mineral areas.
DYNAMIC MODEL OF THE CENOZOIC TECTONIC EVOLUTION OF THE LIAOHE BASIN
CHEN Zhengle, MA Yinsheng, WANG Xiaofeng, WU Tiesheng, WU Honglin, YIN Xiulan, CHEN Xuanhua, HUO Guanhui, WANG Qingfeng, ZHENG Zhiyu, LAN Xiufeng
1999, 5(2): 84-90.
Abstract (154) PDF (181KB)(7)
Abstract:
The petrology of the Cenozoic volcanic rocks and their distribution in the Liaohe basin indicate a continental rift environment;The uparching of the upper mantle revealed by geophysical data has controlled the development of the structures on the surface.Four periods of tectonic stresses were determined from the combination pattern of the Cenozoic fractures.Finally, the authors propose a model of the formation and evolution of the Liaohe basin, combining orogeny with basin formation.
QUASI-DUCTILE FRACTURES AND THEIR GEOLOGICAL SIGNIFICCANCE
WANG Yiqiang, LU Guxian, DU Zitu
1999, 5(2): 91-97.
Abstract (130) PDF (108KB)(7)
Abstract:
A Quasi-ductile fractures is a new type of fractures which is different from either the brittle ruptures or the ductile shear zone.It occurs mainly at the centre of a ductile shear zone and may develop later from a further, shearing of the rocks.Such fractures are often Characterized by breccias composed of mylonites and by vertical and horizontal zoning of mineralization at high temperatures and pressures.Fluid carrying Pb.S etc may partly come from the mylonites.There are decrease or loss of some elements in the wall rocks at the both sides of mineralized belts.Microfissures, cataclastic flows and strain localization are found in them.