摘要
大型-超大型金矿床具有群聚产出的空间分布规律,这种空间产出规律与断裂带的渗透性结构有关。通过应力转移模拟,计算库伦破裂应力(CFS)的变化值,获取断裂带渗透性结构可以为成矿流体通量及其中金属沉淀成矿概率提供半定量约束。胶西北焦家金矿田是我国第一个千吨级金矿田,其内金矿化严格受NE-NNE向的焦家断裂带构造控制,而其深部隐伏的近EW向基底构造带对成矿的贡献尚不明确。为此,我们根据地球物理资料解译的基底构造带空间形态,通过三维有限元模拟计算基底构造带对理想模型和焦家断裂带内库伦破裂应力变化的影响,探讨基底构造对矿床定位的控制机理。研究表明,EW向基底构造带对区域库伦破裂应力的变化有明显影响,模拟结果图像可视作该深度上NE-NNE向浅表断层和EW向基底构造带分别引起的库伦破裂应力变化之和。成矿深度上某一点因基底构造带活动引起的库伦破裂应力变化的值与基底构造带埋深与成矿深度间距的平方呈反比。当基底构造带和浅表断层运动方向指向同一象限时,基底构造带和浅表断层交汇部位的库伦破裂应力变化值相对减小;而基底构造带和浅表断层运动方向指向不同一象限时,基底构造带和浅表断层交汇部位的库伦破裂应力变化值相对增大。焦家金矿带内基底构造带在成矿期发生右行为主的走滑活动,滑动侧伏角不大于30°,滑动位移量略大于浅表的焦家断裂带。基底构造带在成矿期的再活动导致在其与浅表断裂交汇部位形成构造节点(如新城、焦家),引起该处断层破裂的传播受到阻滞,库伦破裂应力增大,而岩石破碎,有利于高渗透性的裂隙-网脉系统的发育和大型-超大型金矿床的产出;在远离焦家主断裂带的前孙家、洼孙家等部位,浅表断裂引起的库伦破裂应力变化不明显,而基底构造带引起的库伦破裂应力�
The giant,super-giant gold deposits always occur in clusters,whose spatial distribution is related to the permeability structures of fault zones. By conducting stress transfer modeling,the change of Coulomb Failure Stress( CFS) is calculated,from which the permeability structures of fault zones can be obtained,and the metallogenic fluid flux and metallogenic probability of metal precipitation can be semi-quantitative constrained. The Jiaojia gold belt is the first place where the kiloton class gold ore field in China was found. In this belt,the gold deposits are structurally controlled by the NE-NEE trending Jiaojia fault. However,the contribution of nearly EW trending basement structure beneath the Jiaojia fault to gold mineralization remains unclear. Therefore,according to the spatial morphology of basement structures interpreted from geophysical data,the influence of basement structures on the CFS was calculated in three-dimensional finite element simulation to reveal the control mechanism of basement structures to deposit locations.The research shows that the EW trending basement structures have apparent influence on the change of regional CFS,and the simulation results imagine can be regard as the sum of the change of CFS caused by NE-NNE trending shallow faults and EW trending basement structures respectively. The variation value of the CFS caused by the activity of basement structures at a certain point in the metallogenic depth is inversely proportional to the square of the distance between the buried depth and the metallogenic depth. When the movement direction of the basement structure and the shallow fault points to same quadrant,the change of CFS near the intersection of the basement structure and the shallow fault decrease relatively. On the contrary,when the movement direction of basement structure and shallow fault points to different quadrants,the change of CFS increases relatively near the intersection of basement structures and shallow faults. The basement structures beneath Jiaojia fault zone h
作者
王偲瑞
杨立强
成浩
李大鹏
单伟
袁建江
WANG SiRui;YANG LiQiang;CHENG Hao;LI DaPeng;SHAN Wei;YUAN JianJiang(State Key laboralary of Gedlogical Proces and Mineral Reowrces,China Universily of Geusciences,Beijing 100083,China;Shandong Gold Mining(laisheu)Limited Company Jiaojia Gold Deposit,Laishou 261400,China;Shaundong Institude of Geolgical Science,Jinan 250013.China;Explorution and Reseurch lustiule,CNACC,Beijng 100039.China;Key Laboratory of Rare Mineral,Ministy of Naturl Resoures,Wuhun 430034,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第5期1529-1546,共18页
Acta Petrologica Sinica
基金
国家重点研发计划(2019YFA0708603、2016YFC0600107-4)
国家自然科学基金项目(41230311、41572069)
高等学校学科创新引智计划(BP0719021)
地质过程与矿产资源国家重点实验室科技部专项经费(MSFGPMR201804)
自然资源部稀土稀有稀散矿产重点实验室开放基金资助项目(KLRM-KF201803)联合资助.
关键词
焦家金矿带
基底构造带
矿床空间分布
库伦破裂应力
数值模拟
Jiaojia gold belt
Basement structure
Spatial distribution of gold deposits
Coulomb failure stress
Numerical modeling
