Geological Characteristics And Metallogenesis Of Hongshan Iron Deposit In Beishan Region,gansu Province

Beishan region underwent complicated tectonic evolvement and magmatic activities during the long geological history,which create excellent geological structural conditions for mineralization and almost 100 deposits of ferrous,non-ferrous,rare,noble metals and non-metal have been explored in this region.This dissertation,supported by the investigation of iron ore in Hongshan region,Beishan,Gusu province project issued by Chinese Geological Survey,put the No.4 and No.5 segments of Hongshan iron ore in Beishan region as main research objects.Based on geological backgrounds and Magnetoelectric geophysical data,we research the characteristic of deposit,identified main ore-bearing horizons,ore texture and structure,occurrence of iron,and analysis the type of deposit and summarize the ore prospecting criteria.The main conclusion and understanding were as follows:1.The forth formation in Dahuoluoshan group of Qinbaikou system is ore bearing stratum in this region,and the ore bearing rock is magnetite-quartzite.Because the ore bearing stratum is controlled by the subsidiary anticline of the Shuanyingshan synclinorium and faults,the ore body on the surface occurs as lots of stripped in the both sides of anticline.The alteration of country rock is mainly and chloritization and tremolitization.2.The occurrence of the ore is consistent with country rock.The ore has small range of grade and has tripe and disseminated structures,and its tripe parallel with the bedded of country rock.3.Abundant occurrence of jasper mass and silicon strip in iron ore indicate that the mineralization has closely relationship with hot brine and high silicon colloid associated with volcanic activity.4.Statistical analysis of bulk phase indicate that the TFe in ore is mainly derived from magnetite and followed by hematite and limonite.5.We newly discovery a iron deposit producer and delineate five prospecting target areas,and the iron reserve(333+334)we estimate in this area is 14.078 million tons.6.Drilling programs confirm that iron ore body exist in the depth of the mining area.The depth of the ore body controlled by drill holes is about 400 m,which is twice as much as before.The newly added ore resource we estimated is 1.99 hundred million tons after exploration engineering.7.Comprehensive analysis show that the genesis of the Hongshan iron deposit should be hydrothermal sedimentary and metamorphic type,and the ore prospecting criteria of the same type deposit in this region has been established.