摘要
成矿构造应力场研究是控矿构造研究、认识矿体空间展布形态、位置、预测及布置探矿设计的基础。依据弹性力学和莫尔库仑剪切破裂理论,推导出形成共轭及在剪切构造带内形成羽列、雁列等构造应力场的产状和形成羽列、雁列主应力大小的数学解析表达式,进而应用计算机对新城金矿床主矿体进行了测算。结果显示:该矿主容矿构造是在NNW向缓倾拉张主应力、NE向陡倾主压应力、焦家构造带平面呈右行扭动下形成的。NWW向中间主应力控制新城Ⅰ号主矿体在NW向倾斜平面上延深的长轴方向。该轴在水平面上投影的倾伏向为281°,与水平面的夹角倾伏角为26°,在N40°E纵投影面上向SW侧伏,侧伏角为45°,富矿柱产状亦与中间主应力轴产状一致。在已获取容矿构造产状基础上,据相关岩石力学性质测试成果,分析并建立了主容矿羽列与控制剪切构造带两者的力学关系和剪切破裂方程式。联立解出成矿应力场的最大和最小主应力的量值,再由陡倾主应力大小估算出该矿头部的成矿深度在2 750m左右。
The study of tectonic stress field is the basis for the understanding of ore-controlled structure,ore body’s spatial distribution and forecasting.According to the elastic mechanics and Mohr-Coulomb shear failure theories,the tectonic stress field conditions giving rise to the conjugation,feather-echelon and en-echelon structures were figured out and thus a mathematical analysis method for calculating the parameters needed in forming the above structures was proposed.This method was applied to the Jiaojia-type Xincheng gold deposit,and the result shows that the main structure hosting the ore bodies in this deposit occurred in a right-twisting structural plane,suffering NNW trending low-angle extensional stress coupled with NE trending high-angle compressive stress.The NWW trending intermediate principal stress that controlled the occurrence of the plunge and lateral trending of the No.I orebody pitches to the direction of NW281° with the angle of pitch of 26° on the horizontal projection,however it pitches to the SW direction with the angle of 45° on the N40°E direction projection.On the basis of the occurrence of host structure and the test results of rock mechanical properties,the authors have built the mechanics relationship and formula between the feather-echelon and the shear structure.According to this formula,the maximum and the minimum principal stress have been solved and the upper limit of the mineralization depth is estimated to be about 2750 m.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第4期312-319,共8页
Earth Science Frontiers
基金
中国地质调查局地质调查项目(1212011220935)
关键词
羽列
构造应力场
莫尔库仑破裂理论
主应力产状
主应力量值
新城金矿
feather-echelon
tectonic stress field
Mohr-Coulomb shear failure theories
occurrence of principal stress
principal stress value
Xincheng gold deposit
