摘要
铜陵市冬瓜山铜矿是中国目前最大的现代化井下坑采铜矿山,目前浅部矿产开发已近成熟;矿体埋深在-690～-1007 m,开采历史已经超过50年.为在冬瓜山铜矿床地区寻找第二成矿空间,查明区内-1～-3 km深度的地层、构造及岩浆岩分布,揭露和成矿密切相关的奥陶系—志留系界面的空间分布,本文针对冬瓜山铜矿强电磁干扰的勘探环境,开展了三维广域电磁勘探.通过现场干扰情况调查和数据采集试验设计了合理的广域电磁数据采集参数,获得了高质量广域电磁数据;在对强干扰区含噪数据进行精细去噪后,开展了拟二维反演;综合区域物性资料、钻孔资料、拟二维反演结果以及巷道揭露的1000 m以浅的地层、岩体和矿体空间分布,开展了基于地质模型和岩石物性引导的广域电磁三维反演,验证了探测区1000 m以浅的精细电性结构,并遵循"从已知到未知,从浅部到深部"的解译原则,推断了-1～-3 km范围内深部岩体及奥陶系—志留系界面的空间分布.研究成果可为冬瓜山矿体深边部找矿、成矿靶区预测及钻探选址提供了地球物理依据.
Abstract
The Dongguashan copper mine in Tongling City is currently the largest modern underground open-pit copper mine in China.The shallow mineral resources in the area have been developed to maturity,with ore bod-ies buried at depths ranging from-690 m to-1007 m,and the mining history has exceeded 50 years.To search for a secondary mineralization space in the Dongguashan copper mine area,to clarify the distribution of strata,structures,and magmatic rocks at depths between-1 km and-3 km,and to reveal the spatial distribution of the Ordovician-Silurian interface closely related to mineralization,a three-dimensional wide-field electromagnetic exploration was carried out in the Dongguashan mining area.In this paper,for the strong electromagnetic interfer-ence exploration environment of the Dongguashan copper mine,reasonable wide-field electromagnetic data acquisi-tion parameters were designed through on-site interference investigation and data collection experiments,obtaining high-quality wide-field electromagnetic data.After fine denoising of the noisy data in the strong interference area,a pseudo-two-dimensional inversion was carried out.Then,based on the geological information,combining regional physical property data,inversion results,drilling data,and the spatial distribution of strata,rock bodies,and ore bodies exposed by tunnels within 1000 m,the three-dimensional inversion of WFEM data guided by geological structures and rock physical properties was carried out.This validated the fine electrical structure of the survey area within 1000 m and,following the interpretation principle of"from known to unknown,from shallow to deep",inferred the spatial distribution of deep rock bodies and the Ordovician-Silurian interface within the range of 1-3 km.It provides geophysics basis for the exploration of deep and marginal ores of the Dongguashan ore body,prediction of mineralization target areas,and site selection for drilling.
基金项目
云南省重点研发计划项目(202303AA080006)
国家自然科学基金项目()
NETL
NSTL
万方数据