1997 Vol. 3, No. 3

Display Method:
1997, 3(3): 1-3,11.
Abstract (62) PDF (156KB)(5)
Abstract:
ANALYSIS OF THE JIASHI,XINGJIANG,EARTHQUAKE AND THE RELATED TECTONIC ACTIVITY
Wu Zhenhan, Wu Ganguo, Sun Baoshan
1997, 3(3): 4-11.
Abstract (116) PDF (333KB)(8)
Abstract:
A major shock of M=6.9 followed by a swarm of strong after-shocks of magnitude between 6 and 7 occurred in the west of Jiashi County of the Xinjiang Uygur Autonomous Region from March 1996 through April of 1997 at the west margin of the Tarim Basin. And historical strong earthquakes had been located in Jiashi and the vicinity before 1990s. The strong seismic activity around the Tarim Basin including Jiashi County is mainly caused by the convergence of the fast northward lithospheric motion of India-Australia plate and the slow westward lithospheric motion of Eurasia plate and the resulting N-S compression, sinistral strike-slipping and faulting of different properties. The regional E-W-trending active marginal faults surrounding the Tarim Basin control the distribution of marginal seismic zones. The strong earthquakes are most likely to occur where the regional E-W trending faults meet the minor NS-NNW, NW and NE-trending faults as exampled by the Jiashi swarm. Although there is little possibility for large earthquake to take place between epicentral areas of the Jiashi earthquake swarm in the near future, occurrences of earthquakes with magnitude between 6 and 7 can not be precluded in the east and south adjoining regions in recent years.
GLOBAL STRESS FIELD CAUSED BY THE CHANGE OF RATE OF THE EARTH'S ROTATION
Wang Lianjie, Zhang Lirong, Wang Wei, Yuan Jiayin
1997, 3(3): 12-20.
Abstract (113) PDF (376KB)(9)
Abstract:
In this paper,a global stress field caused by the change of rate of the earth's rotation is calculated using finite element method.The principal stress resulting from the change of centrifugal inertial force is South-North and East-West oriented,and the magnitude of the stress may reach to tens to several hundreds MPa.The principal stress caused by latitudinal inertial force for a homogeneous earth is Northeast and Northwest oriented.With a varying crustal thickness along the longitude,there will be a zoning of the stress field caused by latitudinal inertial force with the resulting 4 tension zones corresponding to the locations of the present 4 Mid oceanic ridges.
ELASTIC MECHANICS APPROACH OF HELANSHAN NNE TRENDING REVERSED S-SHAPED STRUCTURE
Li Tianbin
1997, 3(3): 21-28.
Abstract (140) PDF (312KB)(7)
Abstract:
The reversed "S"-shaped structure consists of series of NNE-trending folds and faults,which are mutually parallel and en echelon arranged.The component structures are mostly expressed as compress-shear elements,with sinistral motion predominated.They were only qualitatively described previously.This article,however,gives a mathematical-mechanical model for its formation.
COAL CREEP AND GROUND SUBSIDENCE OF FENGFENG COAL MINEⅡ
Wu Lixin, Wang Jinzhuang, Meng Shunli
1997, 3(3): 29-35.
Abstract (115) PDF (277KB)(8)
Abstract:
Creep experiments of coal under uniaxial load show a low creep factor (Z=e1/ec) and a high threshold stress (eth).The samples are taken from the Fengfeng coal field in Hebei Province.Creep parameter sets determined at different stress levels were presented.Calculations of ground subsidence due to underground mining of Fengfeng coal mine Ⅱ using the present experiment results call for farther precautions.
THE INFLUENCE AND CONTROL OF SHEARING ON THE DEVELOPMENT OF THE OPTICAL ANISOTROPY OF ORGANIC MATTER
Zhong Jianhua
1997, 3(3): 36-40.
Abstract (106) PDF (208KB)(9)
Abstract:
Not far from western Baisha town of Luyan county in western Hunan, there is a shallow oil-bearing brittle-ductile shear zone, in which the organic matter has striking optical anistrophy, with Ro,min values ranging from 0.34% to 0.81%, Ro,med values from 1.01% to 1.84%, and Ro,max values from 2.52% to 3.20%, and the maximum bireflectance amounting to 87%, the Ro,max axis of the optical anisotropy ellipsoid being paralled to S foliation. The shear stress is considered to have an influence and control on the development of optical anisotropy of the organic matter.
QUANTITATIVE ASSESSMENT AND ZONATION OF REGIONAL CRUSTAL STABILITY IN CHINA
Sun Ye, Tan Chengxuan, Yang Guisheng, Wang Ruijiang
1997, 3(3): 41-52.
Abstract (224) PDF (438KB)(21)
Abstract:
China, as is located at the intersection of the circum-Pacific tectonic zone and the Mediterranean tectonic zone, has relatively strong active geological structures associated with various endogenic geological hazards. In this case it seems necessary to achieve a quantitative assessment and zonation of the regional crustal stability to better serve the economic construction and hazard reduction. The present paper attempts to present the methods to approach the problem in three steps based on the distribution of the main presently active structural systems and geological hazards as outlined in the text.
ON VERTICAL TRANSFORM FAULT IN CONTINENTAL LITHOSPHERE
Bai Wenji, Yang Jingsui, Re Yufeng
1997, 3(3): 53-58.
Abstract (270) PDF (256KB)(9)
Abstract:
In recent years,a new type of fault that cuts nearly vertically through the entire crust into the mantle is known from geophysical investigations and is named vertical transform fault by the authors.At first,they were recognized only in the lithosphere of High Asia including Tibetan Plateau,and subsequently found in Siberia and Low Asia.They are formed simultaneously with crustal thickening,Moho movement,some moutain-uplifting and basin sinking.The recognition of these faults is of significance in understanding the continental lithosphere and deep dynamics of the Earth.
GEOLOGICAL CHARACTERISTICS OF THE STRATA-BOUND GOLD DEPOSITS IN MID-XUEFENGSHAN MOUNTAIN AND ORE -CONTROLLING MECHANISM
Liu Xiangqin, Meng Xiangang, Zhao Jianguang, Xiao Zhusong
1997, 3(3): 59-67.
Abstract (255) PDF (382KB)(8)
Abstract:
In the middle part of the Xuefengshan mountain exist many types of gold deposits,of which a new type-a strata bound gold deposits often widespread and of high grade has been recently discovered.The gold deposit is closely associated with the feldspathic quartz gray-wacke of the Zhuanqiangwan Formation of the Furongxi Group (Ptfz) and the pebble-bearing feldspathic quartz gray-wacke of the Sinian Changtan Formation(Zc)."T" shaped high grad gold ores usually occur in the confluence of various types of alteration or where the NW-trending structures join the NE-trending structures.
A DISCUSSION ON IDENTIFICATION OF MECHANICAL PROPERTIES OF THE ORE CONTROLLING FAULTS
Zhang Shouting, Li Zhongquan
1997, 3(3): 68-73.
Abstract (125) PDF (241KB)(10)
Abstract:
In nature,the most of ore-controlling faults have experienced repeated movement.Identification of their activity and mechanical properties especially during mineralization,is the key to revealing the tectonic stress field and the structures leading to the control of the ores.This paper has a preliminary discussion of these problems.
ANALYSIS OF MICROSTRUCTURES AND SUPERIMPOSED DEFORMATION IN YISHU FAULT BELT
Hu Ling, Gu Delin
1997, 3(3): 74-79.
Abstract (109) PDF (267KB)(7)
Abstract:
This paper describes the microscopic structural features and superimposed deformation of the Yishu fault belt.The results show that the belt has experienced five active periods of structural deformation.
TECTONIC EVOLUTION OF THE SEDIMENTARY BASINS IN WESTERN LIAONING PROVINCE AND THEIR GENESIS TYPE
Wang Weifeng, Lu Shikuo, Sun Yueping
1997, 3(3): 80-89.
Abstract (233) PDF (406KB)(12)
Abstract:
There are several small Mesozoic coal basins in western Liaoning province.Those basins are also petroleum basins.This paper is a research report of the formation and evolution of the basins.Firstly,geodynamic background of western Liaoning province is studied.Secondly,structural geometry and kinematics of these basins are analyzed based on seismic and magmatic data.Thirdly,the mechanism of formation of the basins and their genesis are discussed.Finally,structural features and trap types of the basin are illustrated by an example.
A NEW HYPOTHESIS ON THE DEFORMATION LAW IN THE TECTONOSPHERE——AS A RESULT OF THE CHANGE OF INCLINATION THE EARTH'S AXIS
Tyapkin K F
1997, 3(3): 90-96.
Abstract (160) PDF (313KB)(6)
Abstract:
A new hypothesis on the formation of structures in the tectonosphere effected by the change of the inclination of Earth's axis and some research results are introduced in this paper.The block systems of tectonosphere and succeeding fault activity are discussed.