Characteristic Of Ore-controlling Structure And Distribution Of Mineralization Intensity In The Sanshandao Gold Deposit,Jiaodong Peninsula,China

Jiaodong is China's major gold camp and gold industrial base.Sanshandao gold deposit is a super-large and typical “Jiaojia” type gold deposit with higher geology research degree.But the distribution of gold grade and its supporting research for construction was relatively weak.Through detailed geological investigation,combinating of gold concentration digital-dimension fractal and multifractal model,we found out the ore-controlling structure in Sanshandao gold deposit.we analyzed the influence factors of gold mineralization intensity in Sanshandao gold deposit.The main achievements were summarized below:Before mineralization,the regional principal compressive stress direction was the NW and the formation of Sanshandao-Cangshang fault and its associated NE-NNE fracture appeared pressure characteristics.The connectivity among every NNE fracture was not good which was not conducive on fluid flow and formation of ore bodies.As the principal stress direction in the zone turned into NNE,near E-W stretch was happened,along with the extension of near SN fracture.This was the main passable structure and ore-hosting structure.After metallogenic,the NW structure(Sanshandao-Sanyuan structure)destroyed a large number of structure and ore body.We identified four main mineralization stages for Sanshandao gold deposit,as pyrite-beresite(?),gold-quartz-pyrite-arsenopyrite(?),gold-quartz-metal sulfides(?),and quartz-carbonate(?).?,stage is the gold main metallogenic stage.The ?metallogenic stage has no directional property in stage and pyrite is cloddy to main ?in this stage.The polymetallic sulfide mainly vein in ?metallogenic stage,and the strike was north-east or north-south.Through the distribution and mineralization of gold orebody parameters style in Sanshandao gold deposit,we can divide the drifts into three level,intensely mineralized drift(for example: drift 46 at-465 m level);moderately mineralized drift(for example: drift 54 at-510 m level);weakly mineralized drift(for example: drift 51 at-510 m level).In digital-dimension fractal method,with the increase of mineralized rank,the threshold became greater and the dimension tended to be smaller.In multifractal spectrum,the multifractal spectra of intensely mineralized drift was narrow than the multifractal spectra of moderately mineralized drift and weakly mineralized drift.Applying the method of multifractal spectrum,we calculated the ?? value in intensely mineralized drift(?)was smallest;medium in moderately mineralized drift;largest in weakly mineralized drift(?).The gold grade distribution in moderately mineralized drift was the most uniformity,the most uneven in weakly mineralized drift.The gold grade distribution in Sanshandao gold deposit suited the method of fractal and multifractal.In the second mineralization stage(?),there was no unified direction of tectonic with with fewer microcracks.The mineralization was mainly controlled by water-rock reaction,and the gold grade distribution was relatively uniform.In the third mineralization stage(?),the structure was intense extending action,causing microcracks increases and the threshold became greater.Ore body was controlled by fractures and the the gold grade distribution was more concentrated.