Spatial Form And Ore-Controlling Factors Of The Ore Bodies Of Iron Deposit In Panzhihua?Sichuan Province

The geotectonic position of study area belongs to the western margin of the Yangtze platform.In this area,the geologic structure is very complex.Volcanic rocks are widely distributed in this area.For a long time,Panzhihua ore bearing rock is considered to be a typical layered rock mass,which is about 30 square kilometers in area.In this paper,through the collection of information on the mining area,combined with field verification,i got the following points:(1)Orebodies of Panzhihua iron deposit are hosted in the fine-medium grained gabbro,medium grain gabbro,fine grained gabbro,fine pyroxenolite and the dolomite of Upper Sinian Dengying Formation.The ores mainly are:(1)Gabbro type iron ore,which is the main ore type of mining area.The main gangue mineral include pyroxene,plagioclase and hornblende,with ophitic.(2)Pyroxenite type iron ore,The gangue minerals are mainly pyroxene,olivine and small amount of plagioclase and hornblende,etc.(3)The massive rich iron ore,The gangue minerals are mainly hornblende,biotite,sulfide and small amount of plagioclase,etc.(2)Ore body shape of the mining area is varied variety,the mainly shape are:(1)Stratiform,stratoid orebody,it is hosted in gabbro.The orebodies are located in the lower part of the rock mass,has the same occurrence as gabbro,about 50 degrees.Development of rhythmic layering is good.There is no intrusive contact relationship between rhythmic layering.(2)Lenticular or veined iron ore body,which is hosted inthe medium grain gabbro,fine-grained gabbro and the marble.The orebody often distributed nearly parallel or skewed with rhythmic layering.(3)The irregular ore body outputed along the magma(pulp)channel.(3)The ore controlling factors are:(1)Crystallization differentiation,Magmatic crystallization differentiation formed the silicate melt in the upper part,rich in iron and titanium oxide melt in the lower part.The lower part invade in dolomite and formed the rhythmic ore body.(2)Slurry penetration,The rich iron titanium oxide(pulp)fluid from the deep or magma chamber penetrated into the dolomite,gabbro along the magma channel,rock mass contact zone or weak zone,and formed the lenticular,veined and irregular ore body.(3)The reform by the emplacement of syenite magmas and granite magma which are formed by homologous magma evolution.The syenite inject into the fine-grained gabbro along the joint or fracture of the surrounding rock.The granite main penetrated into the fine-grained gabbro and marble.The assimilation-contamination is general developed at the the contact zone.(4)After the mineralization,the fault has a certain damage to the ore body.The fault distance is usually small.(4)Sequence of rock massAccording to the space position of rock mass and with relations,the emplacement of the rock mass from morning to night:Fine grained gabbro?fine-medium grained gabbro,medium grain gabbro(rhythmic iron ore body)?leucocratic gabrro,plagioclasite?(penetration type ore bodies,pegmatite type ore body)gabbro pegmatite?hornblende syenite?granite...