1、第五章 断层制图技术(2)第四节 断层模型的类型 一、伸展断层作用 二、挤压断层作用2023-1-172一、伸展断层作用 定义：上盘相对于下盘发生沿断层面倾向向下的运动。一般倾角较陡。通常，每个断层都有不同的滑移量，位移较大的断层称主断层；位移较小的断层称反向断层，或称补偿断层。2023-1-1732023-1-174 在测井曲线上，正断层一般导致地层缺失；在构造图上，在断层与上升盘及下降盘制图地层的交汇处出现间隙。正断层可以是生长的或非生长的；可以是单一的或是复杂的；在剖面上可以是平面的、犁式的或反犁式的；能够向下尖灭，也可以发生变形。5.4 断层模型的类型2023-1-1752023-1-
2、176Normal Faults in Morgantown Sandstone and Birmingham Shale,Bakerstown Station,PA 2023-1-177A small normal fault cutting Miocene tuffs and conglomerates east of Shoshone,California,near Death Valley.2023-1-1782023-1-179除单一的正断层外，伸展区还有三种基本的正断层相交及终止模式：（1）分支断层模式（2）补偿断层模式（3）交叉断层模式5.4 断层模型的类型2023-1-1710
3、（1）分支断层模型 由两个倾向相同且沿走向合并成一个断层的正断层构成。两个断层合并的线称分叉线或交汇线。分叉线两侧断层的垂直断距总和必须守恒。这意味着单一断层的垂直断距等于或几乎等于另一侧两个断层的垂直断距之和。5.4 断层模型的类型2023-1-17112023-1-17122023-1-17132023-1-1714说明三个问题：1、两个断层面的倾向基本相同；2、两个断层在相同等值线处相交；3、分叉线两侧垂直断距相等。5.4 断层模型的类型2023-1-17155.4 断层模型的类型2023-1-1716LK2023-1-17172、补偿断层模型 由两个倾向相反且沿走向呈锐角相交的正断层构
4、成。在相交线上，一个断层终止于另一个断层。相交线两侧的垂直断距保持不变。5.4 断层模型的类型2023-1-17182023-1-17192023-1-17202023-1-1721考虑这一模型：在断层相交线的北西侧，断层1的地层缺失是300ft；而断层2是200ft，它在断层相交线的东南从断层1带走了200ft的位移，为断层1留下100ft的位移。5.4 断层模型的类型2023-1-17225.4 断层模型的类型2023-1-1723 问题：你能看出新断层的方位是分支与补偿断层模型之间唯一的基本差别吗？分叉 合并 补偿 终止5.4 断层模型的类型2023-1-17243、交叉断层模型 两个断
5、层（正断层或逆断层）以一种方式倾向交叉后，两个断层继续向下延伸（好像互不影响）；既不同于分支断层的合并，也不同于断层终止的补偿。5.4 断层模型的类型2023-1-17252023-1-17262023-1-1727相交地垒地堑断层 2023-1-1728对于有限的资料，必须决定相交断层是否同时形成，或具有两个不同的活动阶段。5.4 断层模型的类型2023-1-1729地堑地垒2023-1-1730Fault Intersection on Maps and Seismic Sections The relationships between eroded surfaces,subcrop m
6、aps or seiscrops(all with flap topography)and the correlative cross-sections or seismic profiles are quite illustrated on these blocks diagrams.The geometry on the cross-sections or on seismic lines must match with the geometry on the flat surfaces.When a seismic interpreter recognizes a curvilinear
7、 normal fault on a seiscrop,the fault on a seismic profile must show,in depth,an increasing hade,i.e.,its fault plane must flat in depth.Similarly,when two rectilinear normal faults intersect,on a flat surface,as well as on a cross-section,the youngest fault displaced the oldest.This hypothesis,whic
8、h is only valid when the map(upper surface)is without or with a flat topography,is illustrated by two the lower right blocks.2023-1-1731The relationships observed in extensional structures between horizontal surfaces(geological maps without topography,or seiscrops)and cross-sections(or seismic lines
9、),must also be respected on compressional structures,particularly in those deformed by concentric folding.These relationships are summarized in this block diagram,in which the basic principles of 3D seismic interpretation are depicted.The strike of the more dipping beds gives roughly 2(2=strike of v
10、ertical bed)and the dip of the less dipping beds gives the axial plunge.In other words,in an area with horizontal beds,the axial plunge of the structures is zero and the strike of the vertical beds is parallel to the axial plane of the structures(perpendicular to 3).2023-1-1732This seismic line from
11、 Gulf of Mexico,illustrates a typical example of normal faults in X.The younger fault,dipping to the right,offsets the older on which dips to the left.In a seiscrop,or in a flat geological map,also the younger fault displaces the older one.However,as we will see below,in a time structural map or in
12、a geological map with a significant topography,that is quite more complicated.2023-1-1733In a cross-section(or seismic line)the intersection of the normal faults X faults)are characterized by a graben structure overlying,in the same vertical,an horst structure.,as illustrated on this block diagram.T
13、he mapping of these faults depends on the level of cartography.In upper levels the mapping is relatively easy.We just need to make a dextral rotation of rotate 270 to get the geometry on the ground surface.However,as we will see in the next,the influence of the topography is quite important.2023-1-1
14、734This map illustrates various combinations of faults intersecting at different angles on a planar surface or on a non-conformity.The intersection of the intersected fault(in black)and the surface is invariably offset by the intersecting faults(red and green)in the direction of its dip in the upthr
15、own block.This offset is independent of the intersection angle of the faults,providing the direction of movement of the intersecting fault is dip slip.2023-1-1735Very often explorationists,when interpreting isochrone maps(time structural maps)do not take into account influence of the topography this
16、 possibility,i.e.time contour maps of deformed chronostratigraphic surfaces.In fact,on these maps,as a consequence of the topography,often younger faults are apparently offset by older faults.2023-1-1736TIPS：这些模型可能非常复杂，可能在一个地区包含许多断层。断层模型在侧向延伸时可能并不保持不变。换句话说，在一个地区的断层是补偿断层模型的一部分；在另一个地区可能转变为交叉或分支断层模型的一部
17、分。5.4 断层模型的类型2023-1-1737二、挤压断层作用 定义：断层上升盘沿断层倾向面相对于下降盘发生向上的运动。逆断层制图的常用断层要素：测井曲线上的地层重复。2023-1-17382023-1-17395.4 断层模型的类型2023-1-1740 在挤压区，首先通过测井曲线对比，获取断层数据。通过与周围井的测井曲线对比确定，逆断层地层重复的值与垂直断距大小相同。注意：落差不能由测井曲线对比测量，同样落差也不等于地层重复。5.4 断层模型的类型2023-1-1741逆断层倾向与地层倾向相反：地层重复等于垂直断距。垂直断距大于落差。2023-1-1742逆断层倾向与地层倾向相同：地层重
18、复等于垂直断距。垂直断距小于落差。2023-1-1743逆冲断层的发育环境：挤压板块边界；与褶皱有关的次级断层。5.4 断层模型的类型2023-1-1744美國地質調查所於1996年繪製的最新全球板塊分布圖 2023-1-1745挤压板块边界5.4 断层模型的类型2023-1-1746与褶皱有关的次级断层（断层相关褶皱）5.4 断层模型的类型2023-1-1747秦岭造山带南缘逆冲推覆带不同区段构造剖面 1.宁强大安剖面(张国伟等，2001)；2.石泉县曾溪河口龙湾剖面(张国伟等，2001)；3.城口鲁家坪剖面(张国伟等，2000)；4.巫溪两河口剖面(何建坤等，1997)；5.房县三叶湖两河
19、口剖面(蔡学林等，1988)5.4 断层模型的类型2023-1-17481、单一挤压断层5.4 断层模型的类型2023-1-17492、交叉挤压断层 两个倾向相同的逆断层构成挤压断层模型。在挤压断层模型中，垂直断距穿过相交线后大小不变。5.4 断层模型的类型2023-1-17502023-1-17512023-1-17522023-1-17533、坡坪式挤压断层 坡坪式断面的发展是，断面在非强干层中近似平行于地层移动，并向上斜冲到较高的强干层层位。假如断坡相交另一个非强干岩层，那么断坡可以再次转换到另一个断坪。象其它的断面图一样，推荐解释性等值线图制图方法。5.4 断层模型的类型2023-1-
20、1754R.W.Allmendinger 2023-1-1755These two models illustrate typical structures developed in fold and thrust belts.The photograph below shows a fault-bend fold from the Eohimalayan Fold and Thrust belt developed in Jurassic Kyoto Limestone,Spiti Valley,NW Himalaya,India(photograph by Gerhard Wiesmayr,Vienna).Offset is difficult to estimate but is in the range of several hundreds of metres.2023-1-1756关于断层倾角变化与岩石力学性质的关系？2023-1-17572023-1-17585.4 断层模型的类型2023-1-17595.4 断层模型的类型2023-1-17605.4 断层模型的类型
