| As for the tectonic location,Yanqianshan Iron Ore Mine is located in the intersection part of northeastern margin of the North China Craton,Qidashan-Hujiamiaozi in Anshan(Northwestern the iron ore belt)and the west Anshan-Yanqianshan(East to west iron ore belt),from which the stratigraphic is mainly included Archean Anshan group Yingtaoyuan formation and Proterozoic Liaohe group Langzishan formation.As a typical representative of the BIF deposit in Anshan-Benxi area,this area developed fault structure and possess good,metallogenic prospectsIn this thesis,according to collecte and analysis the data of many years' geological scientific research and exploration in Yanqianshan Iron Mine and Anshan-Benxi Iron Mine,though the field investigation,scientific sample collection,indoor microscope observation about the light and thin section,geochemistry element test analysis in major,trace and rare earth element,analysis the characteristics of the Yanqianshan iron bearing system,shape andsize of the ore body,tectonic type of the mineral deposit,time-space relationship of ore controlling tectonic and the composition and structure of the ore surrounding rock,focuses on the study of the regularity of the ore controlling,tectonic,combining of the Yanqianshan iron ore mine forming environment and tectonic evolution model,obtains the following findings:1.The orebody characteristics:outcropping stratigraphics are Archean Anshan group,early Proterozoic Liaohe group and Quaternary cover,Archean Anshan group are most,includeing the phyllite section at the bottom,magnetite quartzite in the middle and phyllite section in the top.The overall trend of the deposit is near NWW-EW,which is composed of three ore bodies include Fel,Fe3,Fe2,Fel is the biggest.The ore body presents a structure with a S shape in the three-dimensional space.2 Tectonic features:The Yanqianshan iron ore deposit is located in the intersection of two metallogenic belts in Anshan,drape structure and faulted structure are all developed.Drape structure is affected by the late tectonic dislocation,which are relatively fracture,and many small drape structure can be seen in the field,such as the sharp prismatic fold,the wide slow fold,etc,which correspond to the style of Anshan.The fault structure can be divided into three groups of EW,NW and NE.The EW trending fault is the oldest and almost through the whole body.NW trending and NE trending faults,tensional-slip fault,are cut to EW trending faults.3.The tectonic period and control rule of ore:Yanqianshan iron ore mine are mainly controlled by the fault structure,and fold structure controlled subsidiary.So it can be divided into two phases,the EW trending faults is represent the first period of phase change and the NE trending faults is represent the second.The first period of phase change reflects the EW trending shear function in Anshan is almost parallel distributed with the ore body.The F13 fault controls the shape of the Fel body.And most folds in the region is before or after the period.The second period of phase change is influenced by the Hanling fault zone in Yanshan period,which is the main controlling tectonic function in the study area,multi period,large-scale,cutting deep,controlling the ore body of Fe1 and Fe2.Overall,the development degree of the west side of the Yanqianshan iron ore mine is higher than that of the east side.4.Structural background analysis:Archen geotectonic original deposit environment in the Anshan-Benxi region is the arc and back arc basin.The material source of this mine is closely related to the seafloor hydrothermal activity.The siliceous sources in the BIF structure is dominated by the oceanic hydrothermal,with a small amount of terrestrial weathering debris mixed in.5.The tectonic ore controlling evolution model:The tectonic group of the Anshan area is based on the structural pattern of the basement and the cover layer structure,and the same to the Yanqianshan iron mine.The evolution of structure controlling ore body in Yanqianshan includes three stage deformations,including early rock formation contained iron appearance stage,ductile shear stage and fault damage transformation stage.And ductile shear stage controls the iron mine's form,which contains fold and ductile shear band,and it can be divided into three periods,which are closed fold stage,ductile shear stage and ductile shear zone in late stage.The fault damage transformation stage is to dislocate the iron mine which represent two sets of faults in Yanqianshan. |
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