The Study Of The Geological Characteristics And Enrichment Regularities Of Mineralization Of Shanhou Deposit In Laixj City, Shandong Province

Jiaodong peninsula is located in the composite parts of north China massif andYangtze massif.The gold mine in the peninsula is numerous and it has huge reserves，itconstitutes the most important gold producing area in China,the resource and the goldresource which has been proved is the first one in China.The Shanhou gold deposit islocated in northwest of jiaodong peninsulathe which it is the gold deposit concentrationareas,34km south from the Laixi city,30km north from the Zhaoyuan city and located inthe south of Zhaoping fracture zone.Among the eraly and the middle of the mesozoic, ThePacific plate subduct to the Eurasian plate quickly from the direction of southeast to thenorthwest, the Jiaodong region went into the important collision orogenic stage.The main reveal stratum of the Shanhou gold mine is Archean Jiaodong Grop andThe proterozoic jingshan formation. The Archean Jiaodong is located in the northeast ofthe mining，the main lithology is biotite plagioclase metaconglomerate, bearing biotiteplagioclase gneiss; The main lithology of the Jingshan formation is marble. Magmaticrocks are widely distributed in the mining area,mostly are medium-coarsebiotite adamellite and gneissoid-biotitic granite, based on the Analysis of the Zircon U-Pbdating of the Coarse grained biotite monzonitic granite and Gneissic biotite granite,themetallogenic age is148.8±1.5Ma and144.1±1.2Ma,it is late Jurassic epoch. Within the mining area development diorite porphyrite just like dioritic porphyrite andlamprophyre.The Structure in the mine is development,the two groups of fractures arenorth east direction’s ZhaoPing fracture and east west direction’s HeiHuShan fracture.themain Ore controlling structures in area is ZhaoPing fracture and the gold mine is mainlycome from The scope of the footwall of the ZhaoPing fracture main section.The mining area has delineated sixteen industrial ore bodies. Ⅰ-2is the mainorebody, with the shape of veinlike,lenticular,columnar. Ore body has stable occurance oftrend30°-33°；Trend SE,dip angle26°-46°。Ore body has a trend of75m-349m at lengthand has a thick of0.53m-17m.,belongs to rather stable ore body. Metal quanty is7584Kg.Ore quanty is1641012t. Gold grade is4.62×10-6on average.Ore types are mainly pyrilicphyllic alteration and beresitization cataclastic rock type,the texture of ore are mainlyinterstitial structure,solid solution separation structure,crushing structure and metasomaticstructure.The structure of the ore are mainly vein structure,mesh-vein structure and veinletdisseminated structure.Alteration of surrounding rock in the mining area are mainlypotsashfeldspathization, sericitization, silicification, beresitization, chloritization,carbonatation. Among these, beresitization and silicification have the closest relationshipwith gold mineralization.these are also important prospecting marks in this area.Shanhougold deposit has experienced two metallogenic periods, including hydrothermal stage andsupergene oxidation stage. The hydrothermal mineralization period is divided into fourmetallogenic stages: Ⅰ Pyrite-quartz(potassium) phase, Ⅱ Quartz and pyrite(silklithification) phase, Ⅲ Gold-quartz-polymetallic sulfide phase, Ⅳ Quartz-carbonatephase. The main metallogenic stage is the Ⅲ stage.It is showed from the study on inclosure in quartz of the ores,the ore-forming fluidis low salinity（8～10wt%NaCl.eqv）、low density（0.85～0.89g/cm3）NaCl-H2O-CO2system,mineralization temperature is concentrated in230~290°C, mineralization pressureranges from80~101MPa, while mineralization depth ranges from7.09-8.61km. Hydrogenand oxygen isotopes diagram shows ore-forming fluids derive mainly from deep mantle fluids, and accompanied by a small amount of magmatic fluids.Sulfur and lead stableisotope diagram shows that ore-forming materials derive mainly from mantle. From theabove, we can determine that the genetic type of the Shanhou gold deposite is themiddle temperature hydrothermal vein type gold deposit which has mantle-derived fluidsto participate in.The Shanhou gold deposit deposit’s Industrial ore bodies is strict controlled by northeast direction’s Zhaoping fracture, because of the shielding effect gouge hydrothermal ore,resulting in ore bodies are produced in the main fracture surface footwall; enriched ore inthe fracture site and more easterly strike, dip slowed by the steep location;and it haspiecewise enrichment characteristic. The analysts believe that Zhaoping faultmineralization dextral inverse performance characteristics of breaking activity and orebody has obvious regularity of lateral prostration,the direction of lateral prostration ofthe ore is north east,the angel of lateral prostration is about75°. Combining spatialvariation of ore controlling structure research analysis, segmentation enrichment law, basicrules and the industrial side volt ore mineralization enrichment spatial orientationmechanisms on the law, the preliminary view that the Shanhou gold deposit in the deeppresence of another mineralization enrichment section is the next focus of prospecting.