| 地堑形成的力学机制 |
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| 引用本文： | 张文佑,李荫槐,马福臣,钟嘉猷.地堑形成的力学机制[J].地质科学,1981,0(1):1-11. |
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| 作者姓名： | 张文佑 李荫槐 马福臣 钟嘉猷 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 地堑是受地壳断裂体系控制的狭长断陷带,其空间分布常常按一定的规律排列组合而成为地堑系或地堑带。近年来地球物理与地质相结合的研究表明,地球不仅沿垂向分成若干壳层,而且这些壳层沿横向还划分为若干块体,它们的成分、力学性质和厚度等都不尽然一样。因此,地球无论从整体或局部来看,都不能认为它是均一的。
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| 关 键 词： | , |
| 收稿时间： | 1980-03-31 |
| 修稿时间： | 1980-03-31; |
ON THE MECHANICAL MECHANISM OF THE FORMATION OF GRABEN |
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| Chang Wenyou,Li Yinhuai,Ma Fuchen,Zong Jiayou.ON THE MECHANICAL MECHANISM OF THE FORMATION OF GRABEN[J].Chinese Journal of Geology,1981,0(1):1-11. |
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| Authors: | Chang Wenyou Li Yinhuai Ma Fuchen Zong Jiayou |
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| Institution: | Institute of Geology, Academia Sinica, Beijing |
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| Abstract: | The formation of Graben is generally controlled by crustal fracture system on different levels of depth and is actually a fault-depressed belt between faulting-blocks,opening and closing with changes of stress-field (shearing-tension,shearing-compression) between faulting-blocks.Thus,in view of geomechanics,graben is generally a proto-geosyucline. The distribution of graben system is always in a zigzag pattern that is related with the zigzag fractures.Moreover,the occurrence of these zigzage fractures often have some relation with tensional stress field on the background of regional com-pressional stress field.As a result,the graben system can be frequently found on the top of an old uprising or the bottom of an old depression.The characteristics of graben system depend mainly on a series of factors,such as the mode depth,magnitude and manner of ativity of the old fracture system which controls the development of graben.The geomechaiiical and geohistoric analyses indicates that once a region is compressed,other regions adjacent to it must be tensed,and vice versa;as for a particular region,if it is compressed at one stage,it will probably be tensed at the next stage.That’s why we say that graben may have been generated by tension in some regions as well as by compression in other regions.Thus,,the graben systems,either tensional or compres-sional,may have undergone alternately tensional and compressional processes in their development which may result in different response in their sedimentary formation and magmatic activities.Therefore,from the mechanical behavoir,the graben systems can be classified into three categories: tensional,shearing-tensional and shearing-compres-sional.They developed on different levels) of depth and with varied magnitude of activity and show significantly different characteristics in their magma and sedimentary formations and deep-seated geophysical field.Hence the graben systems can also be divided into four orders i.e.superficial,foundational,crustal and lithospheric.Under tensional stress the grabens developed in the succession of superficial-foundational-crustal-lithospheric,in other words,it is a transitional process from continental crust to oceanic crust.While under compressional stress,their evolution was in an opposite direction,that is,from oceanic crust to continental crust.Since the formation and development of graben systems are in close relation to faulting systems,the problem of the driving force for graben activity should be explored in the light of world-scale fracture network.The so-called "mantle material uprising" may be a source to form a tensional stress field and to promote the formation of a graben.However,the principal factor causing the uprising of upper mantle materials is the fracture penetrating into lithosphere which provides a passage for them. |
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| Keywords: | , |
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