| Pulang copper deposit located in east porphyry belt of the Geza island arc in southern of the Yidun island arc belt,it is one of the most important prospecting result in recent years of China.This paper is mainly to construct structure of deposit scale as research object,based on detailed field geological investigation,especially for investigation of roadway system structure in the first mining area,combined with a large number of previous research data analyzed rocks and ore-controlling structure,such as the knowledge gained:1.Statistics analyzed 828 attitude of faults in the first mining area showed that 3660 middle only developed 1 sets of fault groups and the strike range from 65° to 135°;3700 middle developed 4 sets of fault groups and the strike range from 10° to 35°,60° to 90°,100° to 120° and 150° to 180°;3720 middle developed 4 sets of fault groups and the strike range from 20° to 50°,55° to 80°,110° to 130° and 140° to 180°;3735 middle developed 4 sets of fault groups and the strike range from 10° to 25°,50 to 90°,120° to 140° and 155° to 180°.Observed tectonic rocks under the microscope,speckle structure is widely developed,mylonitic zone and cataclastic zone has obvious zonation,the overall reflecting tectonic rocks experienced from the evolution of pressure to tension.2.Statistics analyzed 2784 attitude of joints showed that:3720 middle of the first mining area developed 3 preponderant joint groups,the strike range from 40° to 70°,90° to 110° and 120° to 150°;3735 middle developed 4 preponderant joint groups,the strike range from 400°to 60°,65°to 90°,95°to 1300°and 1400°to 175°;Statistics ore bearing property of joint show that the ore bearing joints was mainly divided into two preponderant groups,the strike range from 30° to 65° and 90° to 130°;Non ore joint has 4 preponderant joint groups,the strike range from 350° to 10°,20° to 30°,40° to 60° and 70° to 110°;Surrounding rock in Tat2 developed 3 preponderant joint groups,the strike range from 350° to 10°,60° to 90° and 100° to 110°.3.Based on the detailed study on the characteristics of rocks and ore-controlling,and setting up 3D model of the fault,the fault of the mining area is divided into three structural zones:NW-NNW direction,NWW direction and NE-NEE direction.The regional NNW Heishuitang fracture has the property of rock and ore hosting,is the pro-mineralization structure;Two stage faults of NWW,NE-NEE direction and NW and NE intersection of ore-controlling structure in the first mining area has obvious nature of metallogenic tectonic;The joints distributed of two stage structure in NW-NWW and NE direction are ore bearing structure,control the spatial distribution of ore vein;SN direction and NE-NEE direction structure of superimposed on the mineralization structure should be formed in after-mineralization,with the transformation effect on early tectonic and ore body.4.Analysis of the regional structure and the conjugate shear joints,combined with field observation research,and determine the tectonic principal stress direction(?1)can be divided into 6 groups,the azimuth respectively range from 15° to 43°,63° to 70°,15° and 183°,223° to 258°,300° to 329°and 352° to 0°.It is shown that direction of the maximum principal stress undergoes the process of rotating counterclockwise and then clockwise.According to relationship between the ore and non ore conjugate joints,preliminary determination of maximum principal stress of tectonic stress field in pro-mineralization,metallogenic period,and after mineralization,and changing process of stress range:NEE-NE(pro-mineralization)to NE,near SN,NNW(metallogenic period)to NW-NNW,near SN,NE,near EW(postmineral).It shows that pro-mineralization is mainly from NEE-NE compressive,and the NW main structure in the mining area is characterized by compaction.Mineralization period is mainly from NE,near SN,NNW compaction and the NW main structure in the mining area is converted into tensional and torsional characteristics.5.Regional NNW faults control the output of Pulang area rock belt,a series of complex fault and fracture systems are created by the intersection of several groups,which provide a good space for the emplacement of the late rock mass and the migration and precipitation of the ore bearing hydrothermal fluid.The output and morphology of the orebody in the first mining area are strictly controlled by the intersection of NNE and NE faults. |
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