山东禹城李屯地区重磁异常特征与找矿预测

Magnetic Field Anomany Characteristics and Ore Predictions in the Litun Area of Yucheng,Shandong

近年来,山东禹城取得了富铁矿找矿重大突破,具有良好的找矿潜力,但区内尚有多处局部异常尚未查证。该区新生界厚度大(900~1100 m)、磁铁矿体埋藏深,矿体引起的地球物理异常弱,找矿难度大。为系统总结该区磁铁矿异常特征,为钻孔部署提供依据,重点剖析了禹城李屯地区航空重磁平面异常特征、地面高精度磁测异常特征,总结了矽卡岩型铁矿主要重磁异常找矿标志,主要为化极磁异常、剩余磁异常、垂向导数和总梯度模的异常中心,圈定了叠道村和于庄村2处找矿靶区。通过地震约束下的2.5D重磁剖面反演,推断了矿体赋存位置,指导部署了验证钻孔孔位,经钻探验证在禹城市李屯地区叠道村异常取得重大找矿新突破。研究成果对于该区下一步找矿勘查和其他深覆盖区矽卡岩型富铁矿找矿具有指导作用和借鉴意义。

Recently,significant breakthroughs have been made in the exploration of rich iron deposits in Yucheng,Shandong.However,there are still multiple local magnetic anomalies in the area that have not been verified,which have a promising ore-prospecting potential.However,the Cenozoic Erathem in this area is very thick,about 900-1,100 m,and the magnetite orebody is deeply buried,which leads to weak signals of geophysical anomaly,making it challenging to find the iron ores through surface exploration.In order to systematically summarize the abnormal characteristics of magnetite in this area and provide a basis for drilling deployment,the paper focuses on analyzing the abnormal characteristics of airborne gravity and magnetic plane and the abnormal characteristics of high-precision magnetic survey on the ground in Litun area,Yucheng,and summarizes the main prospecting signs of gravity and magnetic anomalies of skarn type iron ore,which are mainly the anomaly centers of polarized magnetic anomalies,residual magnetic anomalies,vertical derivatives and total gradient modes.Accordingly,two prospecting targets in Diedao Village and Yuzhuang village were delineated.Through the 2.5D gravity and magnetic profile inversion based on the electrical seismic constraints,we delineated two ore target areas,which can further guide the deploying the locations of the verification drilling holes.Significant breakthroughs in ore prospecting have been made in the Litun area of Yucheng City after the drilling verification of stacked-channel anomalies.The results in this study are of great significance and guidance for the future mineral exploration in this area and the search for iron-rich skarn-type ores in other deep ore hidden areas.