Magnetic Fabric And Fluid Inclusion Plane Of The Gold Deposits In Zhaoping Fault Zone, Shangdong, China

In order to discuss the structure character, fluid inclusion and mineralizing dynamics of the gold deposits in Zhaoyuan-Pingdu fault zone, we have carried on research to the magnetic fabric and fluid inclusion plane, investigated the magnetic fabric and the fluid inclusion plane and their correlations during the ore-forming period, analyze the tectonic deformation, fluid displace, force of ore-forming and their correlations during the ore-forming period .The results are as follows:(1) The P value (the degree of AMS) of the 82 points where we sampling which is <1.1 takes 68%, which shows ore-forming is major influenced by fluid, and then the tectonic deformation. The curves of F and L values change coordinate with P, but have negative correlation with changes of gold grade.(2) The magnetic foliation of Damoqujia ore mine in N60°E-striking mainly coordinates with the strike of the Zhaoping fault, and its space distribution of samples is coordinate with the mainly fault of Zhaoping fault zone. The magnetic foliation dominated by mobilization shows the orientation distribution of minerals before which is suffered deformation. The mobilization of magnetic foliation of Dayingezhuang is remarkable.(3) The magnetic foliation of Dayingezhuang ore mine distributes mainly in SN, NE and NW directions. The magnetic foliation that of the No. 1 ore body mainly in sub-NE and ENE directions and that of the No. 2 ore body mainly in NW direction, which probably reflects the differences of the contribution provided by multi-stages of structure- fluid- ore-forming. (4) Petrography of FIP and fluid inclusion study shows:FIP in the quartz veins containing thegold in Xiadian ore mine is developed along three dirctions, approximately EW, NE and NW directions; FIP in EW is formed first, Most fluid inclusions are CO₂-bearing three-phase type; FIP in NE is developed most completely, and later than that in EW, Most fluid inclusions are NaCl-H₂O type; In NW direction is the latest stage, Most fluid inclusions are NaCl-H2O type.(5) From microthermonertry of the two-phases FIP in Xiadian ore mine, the covariance of the salinity and ice point shows gradually getting lower trendly. The fluid inclusion with lower Th-Tmice occurs in sub-NW direction, with the homogeneous temperature range 130-250℃, which reflects the gradually cooling of the hydrothermal period, and shows that the mineralization process is drawing to a close. Early fluid filling along with nearly SN fracture to mineralize, and after the fluid releasing of a large number of volatile, the EW fracture superposed them. As the main mineralization fluid filling along the NE fracture to form the main ore-controlling fractures, the late-stage mineralization fluids may be filling along NW cracks.(6) Combining the record of MF and FIP in the mineralization process specific tectonic deformation and fluid flow of information, with the tectonic evolution, according to MF to restore the NW secondary fracture.Combined FIP to discover the early mineralization, the main mineralization and later-stage mineralization Fluid filling along EW, NE and NW direction, and the minimum caught temperature of Fluid inclusions was in the gradually decreasing trend. Key words: In order to discuss the structure character, fluid inclusion and mineralizing dynamics of the gold deposits in Zhaoyuan-Pingdu fault zone, we have carried on research to the magnetic fabric and fluid inclusion plane, investigated the magnetic fabric and the fluid inclusion plane and their correlations during the ore-forming period, analyze the tectonic deformation, fluid displace, force of ore-forming and their correlations during the ore-forming period .The results are as follows: (1) The P value (the degree of AMS) of the 82 points where we sampling which is <1.1 takes 68%, which shows ore-forming is major influenced by fluid, and then the tectonic deformation. The curves of F and L values change coordinate with P, but have negative correlation with changes of gold grade. (2) The magnetic foliation of Damoqujia ore mine in N60°E-striking mainly coordinates with the strike of the Zhaoping fault, and its space distribution of samples is coordinate with the mainly fault of Zhaoping fault zone. The magnetic foliation dominated by mobilization shows the orientation distribution of minerals before which is suffered deformation. The mobilization of magnetic foliation of Dayingezhuang is remarkable. (3) The magnetic foliation of Dayingezhuang ore mine distributes mainly in SN, NE and NW directions. The magnetic foliation that of the No. 1 ore body mainly in sub-NE and ENE directions and that of the No. 2 ore body mainly in NW direction, which probably reflects the differences of the contribution provided by multi-stages of structure- fluid- ore-forming. (4) Petrography of FIP and fluid inclusion study shows:FIP in the quartz veins containing the gold in Xiadian ore mine is developed along three dirctions, approximately EW, NE and NW directions; FIP in EW is formed first, Most fluid inclusions are CO2-bearing three-phase type; FIP in NE is developed most completely, and later than that in EW, Most fluid inclusions are NaCl-H2O type; In NW direction is the latest stage, Most fluid inclusions are NaCl-H2O type. (5) From microthermonertry of the two-phases FIP in Xiadian ore mine, the covariance of the salinity and ice point shows gradually getting lower trendly. The fluid inclusion with lower Th-Tmice occurs in sub-NW direction, with the homogeneous temperature range 130-250℃, which reflects the gradually cooling of the hydrothermal period, and shows that the mineralization process is drawing to a close. Early fluid filling along with nearly SN fracture to mineralize, and after the fluid releasing of a large number of volatile, the EW fracture superposed them. As the main mineralization fluid filling along the NE fracture to form the main ore-controlling fractures, the late-stage mineralization fluids may be filling along NW cracks. (6) Combining the record of MF and FIP in the mineralization process specific tectonic deformation and fluid flow of information, with the tectonic evolution, according to MF to restore the NW secondary fracture.Combined FIP to discover the early mineralization, the main mineralization and later-stage mineralization Fluid filling along EW, NE and NW direction, and the minimum caught temperature of Fluid inclusions was in the gradually decreasing trend.