Genesis And Prospecting Comprehensive Model Of BIF-Type Iron Deposit In Eastern Shandong Region

BIF-type iron ore is an important type of iron ore.Its resources and exploitation amount rank first in the world.The rich ore formed by BIF-type iron ore accounts for about 70%of the world's rich iron ore reserves and more than 90%of the world's iron ore production.The Eastern Shandong area and its North China plate are important distribution areas of BIF-type iron deposits in China.This paper takes Guocheng Iron Mine in Haiyang City as the research object.On the basis of collecting predecessors'geological data and field geological survey,through rock geochemical characteristics and geological characteristics of deposits,the source of materials and the degree of metamorphism are discussed,the prospecting criteria are determined,and the comprehensive prospecting model is summarized.The main understanding and research results are as follows:?1?The Guocheng iron ore mainly occurs in the metamorphic rocks of the Paleoproterozoic Jingshan Group.Iron ore is mainly rich in SiO₂ and TFe₂O₃,and also contains a small amount of Al₂O₃,MgO and CaO.This material combination indicates that the Guocheng iron ore deposit is dominated by marine chemical deposition,but contains a small amount of debris or mud.?2?The iron ores in Guocheng have light rare earth depletion,high Y/Ho and Sr/Ba ratios and positive La and Y anomalies,indicating that iron ores are deposited in marine environment,while strong positive Eu anomalies indicate that volcanic hydrothermal fluid is involved in the formation of iron ores.The Ti/V ratio has obvious characteristics of volcanic formation,which also indicates that the ore-forming materials are derived from submarine volcanic activities.The weak negative Ce anomaly indicates that there might be an anoxic atmosphere at that time.?3?The hydrogen and oxygen isotope values of wall rocks and ores indicate that the mineralization of iron ores involves the addition of submarine volcanic hydrothermal fluid and Precambrian seawater,and the later hydrothermal fluid with migmatization characteristics has the function of transformation and enrichment.?4?The regional metamorphic facies is amphibolite facies by means of electron probe analysis of biotite and amphibole from Guocheng Iron Mine.?5?Based on geological information and geophysical information,a comprehensive prospecting model is established.