鞍山深部铁矿综合地球物理研究

Comprehensive Geophysical Study on Deep Iron Ore in Anshan Area

在我国众多沉积变质型铁矿矿床中,鞍山铁矿以其成矿作用和地质、地球物理特征具有明显的代表性。通过开展航空物探工作,确定了磁异常范围和重力异常区域,并通过在异常区域开展可控源音频大地电磁法查证工作,目的是研究异常成因、深部构造及推断可能隐伏铁矿体的埋深、宽度、规模及产状。通过收集工区地质资料并结合CSAMT勘查成果综合分析,发现深部低阻异常,并初步确定了低阻异常的位置、规模等分布特征及其成因;发现了2个有意义的隐伏低阻异常体,推测是由磁铁矿(化)体引起;基本查明了工区内的地层分布特征;推断了6条隐伏断裂构造及其产状特征;对工区内各类岩矿石露头实施了电性参数测量,获得工区内岩矿石的电性特征。本次工作,为鞍山-本溪地区的铁矿资源潜力的快速评价提供了不可或缺的基础资料,为指导下一步深部勘查工作提供了依据。

Anshan Iron mine,owing to its＇ mineralization,geology and geophysical features,becomes the main representative in many sedimentary metamorphic iron-ore deposits in China.The area of magnetic and gravity anomaly is determined by airborne geophysical prospecting and the controlled source audio frequency magnetotelluric（CSAM）is applied to this anomaly region in order to research the anomalous reasons,deep structure and to deduce the depth,width,scale,occurrence of latent iron ore body.Through the collection of geological data and combining the exploration results of CSAMT comprehensive analysis,the deep low resistivity anomaly region is found and the distribution feature and origin of the location and scale of low resistivity anomaly is determined roughly;two significant latent low resistivity anomalies which might be caused by the magnetite body are found;the stratigraphic distribution in the work area is basically identified;the six latent fault structures with its occurrence characteristics are deduced.In addition,the electrical feature of the rocks and minerals in this region is acquired by making a test to every type of rock and mineral in the laboratory.This project provides indispensable and basic materials for the quick estimation of iron ore resources in Anshan-Benxi region and helps a lot for the next deep exploration.