青海南戈滩矿区地球物理特征及找矿模式  

Geophysical Characteristics and Prospecting Model of Nangetan Mining Area in Qinghai Province

作　　者：陈瑞林[1] 马德锡[1] 陈方博[1,2] 李文良[1] 陈孝强[1] 王春生[1] 

机构地区：[1]武警黄金地质研究所,河北廊坊065000 [2]中国地质大学(北京),北京100083

出　　处：《黄金科学技术》2013年第4期54-59,共6页Gold Science and Technology

基　　金：中国地质调查局地质矿产调查项目"青海都兰-同德-甘德金多金属矿产调查评价"(编号:1212011220665)资助

摘　　要：南戈滩矿区位于青海省都兰县柴达木盆地东南部,是一个与闪长玢岩有关的矽卡岩型铁多金属矿床。以闪长玢岩岩脉为中心,矿床分为南北2个矿带。矿体赋存在断裂蚀变带中,闪长玢岩脉、矽卡岩化带、矿体和断裂产出一致。对矿区不同的岩(矿)石进行了磁性和电性参数的测定和统计。统计结果表明:矿体的磁性强、极化率高、电阻率低;而围岩的磁性低、极化率低、电阻率高。矿体和围岩存在明显的物性差异,为在本区开展磁法和电法工作提供了物性前提。通过在矿区开展1∶1万磁法和激电法扫面工作,圈定了3处磁异常和1条激电异常带。在磁、电异常重合的地段布设了3条SIP频谱激电测深剖面,圈定了3个SIP极化率断面异常,异常走向NE,倾向近直立,经钻孔验证,SIP极化率异常由矿(化)体引起。SIP的电阻率异常在矿(化)体上方显示有高阻异常,这可能是矿体赋存的裂隙空间对电流排斥的结果,所以矿体上表现的电阻率异常并不一定都是低阻。以物探在南戈滩矿区具有较好的找矿效果为基础,提出了在南戈滩矿区及其外围寻找以铁为主的多金属矿床模式:首先用磁法和激电中梯进行1∶1万扫面工作,圈定磁异常和激电异常,然后在同时存在磁异常和激电异常的地表进行SIP频谱激电测深剖面测量,剖面垂直地表磁异常和激电异常测量,圈定SIP断面极化率异常,对极化率异常进行工程揭示。The Nangetan mine located in the southeast of Qaidam Basin in Dulan County,Qinghai Province,is a skarn type iron-based multi-metal deposits related to diorite porphyry.The mineral deposit can be divided into two ore belt areas, north area and south area, by diorite porphyrite dikes.Ore bodies occur in the fracture altered zone, and the outputs of diorite porphyrite veins,skarnization belt,orebody and fault are consistent.Through the measuring and the statistics of the magnetic and electrical parameters of the different rocks and ores ,what was known is there is the strongest magnetic, highest polarization rate and the lowest resistivity for the ore bodies, while lower magnetic and polarization rate and higher resistivity for surrounding rock.The differences between the ore bodies and surrounding rock are obviously, and it is the physical foundation for the works of magnetic method and electrical method in this area.In recent years,the author carried out the works of 1：10 000 magnetic nlethod and IP method in mine sweeping surface, and delineated three magnetic anomaly areas and one IP anomaly area.By setting up three SIP spectral IP sounding profile in the areas where overlapped by the magnetic and the electric anomaly. Then, three SIP polarizability anomalies areas, with abnormal trend of northeast and the tendency of nearly erect, were delineated.The drilling results show that the anomaly of SIP polarization caused by the ore body （mineralization）, and the anomaly of the ore＇s （mineralized bodies） SIP resistivity showed different anomaly in resistance.High resistivity anomalies may be caused by the rejection of the current in the fractured ore,so the performance of resistivity anomaly is not necessarily low resistance.Based on the prospecting effect of geophysical prospecting in Nangetan mine, the model for searching the polymetallic deposit dominated by iron in Nangetan and the surrounding areas was proposed：using magnetic method and IP intermediate gradient for 1：10 000 scanning to delineat th

关 键 词：极化率 电阻率 SIP频谱激电 物理特征 找矿模式 南戈滩 青海省 

分 类 号：P631[天文地球—地质矿产勘探]