摘要
呷村火山成因块状硫化物矿床是“三江”地区的超大型含金富银多金属矿床 ,其综合找矿模式的建立对“三江”有色、贵金属成矿带的成矿预测具有重要意义。文章在大量实测物探资料的基础上 ,结合区域地质、遥感和矿床地质资料 ,从 6个方面总结了该矿床的综合找矿模式 :即大地构造背景 ;局部 (矿区 )成矿地质环境 ;地质找矿标志 ;区域物探、化探、遥感示矿要素 ;岩石、矿石物性特征 ;综合物 (化 )探异常特征。并给出了针对呷村型矿床的勘探程序和最佳勘探方法组合 ,对指导区域找矿及勘查工作部署具有重要意义。
The Gacun volcanics_hosted massive sulfide (VHMS) deposit is the largest gold_bearing and silver_rich polymetallic deposit in southwest 'Three River' area, and hence a comprehensive prospecting model is needed for regional ore prognosis. Extensive geophysical experiments, such as magnetics, Control Source Audio Frequency Magnetotellurics (CSAMT), Transient electromagnetic Method(TM) and high density electric method, were conducted in the deposit. The results obtained, combined with other studies such as mineral geology, geochemistry, remote sensing, have led to the formulation of a comprehensive prospecting model followed by six principal headings: (1) Regional geological setting; (2) Local geological setting; (3)Geological prospecting criteria; (4)Regional geophysical (geochemical) and remote sensing definition of the deposits; (5) Physical properties of the ore and host rocks; (6)Geophysical expression of the deposits. According to the six principal headings, the ore_prospecting model for VHMS deposits can be summarized as follows: the deposits were produced in back_island arc rift settings related to extensional regimes, and controlled by local fault basin. The magmatic activities were moderate and lasted for a long time, and the intrusion evolved from acid to basic, with the acid magmatism being dominant. The geological prospecting criteria include the presence of copper mineralization or vein type lead_zinc mineralizations which fill in rock cracks, the presence of oxidized sulfide minerals such as malachite and azurite, the existence of the intrusion center and some characteristic rocks such as magmatic_hydrothermal breccia, barite, and dolomite, and the presence of such alterations as chloritization, sericitization and silication. The deposits and neighboring areas show positive magnetic anomalies and gravity gradient anomalies in regional map, the deposits lie at the intersection points between the remote sensing circular structure and the linear structure, and there exist regional geochemical Pb, Zn, Cu, Ba and As anomalies. The massive orebodies are characterized by high density, low or negative susceptibility, high polarizability and low resistivity; nevertheless, the vein_stockwork orebodies assume moderate density, low susceptibility and high polarizability. Correspondingly, the deposits show low magnetic, low resistivity and high polarization anomalies. In addition, this paper summarized the technologies used at various stages in the exploration of VHMS deposits, which are of great significance in regional reconnaissance and evaluation.
出处
《矿床地质》
CAS
CSCD
北大核心
2001年第4期313-322,共10页
Mineral Deposits
基金
国家"九五"科技攻关 914项目 (编号 :96_914_0 3_0 1)
