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本文以德勒诺尔铁矿区发育的节理为研究对象,在约20km2的研究区内布置了93个观测点,在野外共观测三百余组节理,采用数学统计方法,对节理进行分期配套,确定区内主要发育3组高倾角平面X剪节理,通过节理之间相互错断、限制关系对节理期次进行配套分析,并对不同期次构造应力场形成的共轭剪节理进行了研究,利用吴氏网绘制各观察点的主应力图解,获得各点应力轴(σ1,σ2,σ3)的产状。研究得出本区第1次构造应力场最大主压应力轴(σ1)的优选产状为181°∠8°,中间应力轴(σ2)为141°∠81°,最小主应力轴(σ3)为89°∠5°,可能是区内的主体构造格架的动力来源,在区内形成了近EW向的复式背斜及叠瓦状逆冲断裂。第2期构造应力场最大主压应力轴呈NE—SW向,最大主压应力轴(σ1)的优选产状为250°∠12°,中间应力轴(σ2)为56°∠78°,最小主应力轴(σ3)为143°∠11°,为区内形成NW—NWW向展布的逆冲断裂的主要动力来源。第3期构造应力场最大主压应力轴呈NNW—SSE向,最大主压应力轴(σ1)的优选产状为344°∠3°,中间应力轴(σ2)为79°∠80°,最小主应力轴(σ3)为252°∠13°,可能为区内NW、NE向展布的张性断裂的主要动力来源。研究总结了区内不同期次构造应力场的特征,并对动力来源进行了初步探讨。
In this paper, the joints developed in the iron ore district of De Lenoir are studied. 93 observation points are arranged in the study area of about 20km2. Three hundred groups of joints are observed in the field. Mathematical statistical methods are applied to the joints, Three groups of high-shear plane X-shear joints are mainly developed in this area. By means of the mutual relations between the joints, the analysis of the relationship between the joints and the joints is carried out and the conjugate shear joints formed by the different stages of the structural stress field are studied. The principal stress diagrams of each observation point were drawn by using Wu’s mesh to obtain the shape of the stress axis (σ1, σ2, σ3) at each point. The results show that the maximum principal compressive stress axis (σ1) of the first tectonic stress field in this area is 181 ° ∠8 °, the middle stress axis (σ2) is 141 ° ∠81 °, the minimum principal stress axis (σ3) Is 89 ° ∠5 °, which may be the main source of tectonic framework in the area. In the area, there are nearly EW-oriented double anticline faults and imbricate thrust faults. The maximum principal compressive stress axis of the tectonic stress field in the second tectonic stress field is in the NE-SW direction. The maximum stress axis (σ1) is 250 ° ∠12 ° and the intermediate stress axis (σ2) is 56 ° ∠78 ° The main stress axis (σ3) is 143 ° ∠11 °, which is the main source of thrust for NW-NWW distribution in the area. The maximum principal compressive stress axis of tectonic stress field in the third period is NNW-SSE, and the maximum stress axis (σ1) is 344 ° ∠3 ° and the intermediate stress axis (σ2) is 79 ° ∠80 °, the minimum The main stress axis (σ3) is 252 ° ∠13 °, which may be the main source of tension for NW and NE spreading in the area. The characteristics of tectonic stress field in different periods in the area are summarized and the sources of power are discussed.