滇东北巧家松梁铅锌矿床构造特征及构造地球化学

Structural Characteristics and Fault Tectono-geochemistry of the Songliang Lead-Zinc Deposit in Northeast Yunnan, China

巧家松梁铅锌矿床为川-滇-黔铅锌多金属成矿域内新发现的小型铅锌矿床,矿体产出严格受断裂构造的控制。在精细解剖矿区构造控矿特征的基础上,本文系统采集了不同中段的断裂构造岩并进行测试,通过因子分析方法讨论断裂构造地球化学元素组合特征,并绘制断裂构造地球化学异常-地质图,进行找矿预测。研究表明:该矿床不同中段断裂构造岩微量元素主要表现为地层岩石元素组合(Zr、Th、Rb、Ti、Hf、Be、∑REE、Sr、Sc、V、(U、Co))、铅锌矿化元素组合(Ga、Ag、Cd、Sn、Ge、Cu、Ba、In、Pb、(Zn))及中高温矿化元素组合(Mo、Co、Ni、(Mn)),而且不同矿体上部中段的构造岩因子元素组合相似,说明各矿体应为同一成矿流体作用而成,Ⅰ号矿体下部出现了方铅矿化和闪锌矿化元素组合因子的分离,可能反映了成矿流体组分的变化或是多阶段成矿流体叠加的缘故,各中段构造岩因子分析均表明重晶石化与铅锌成矿关系密切,这与野外地质现象相吻合,说明重晶石化是重要的找矿标志之一。构造地球化学异常的分布规律,不仅勾绘了矿体的产状,还反映了矿体显著受构造控制的特征,同时可以推测成矿流体的运移方向,并为找矿预测提供定位靶区。

The Songliang lead-zinc deposit, located in the Sichuan-Yunnan-Guizhou lead-zinc mineralization domain, is strictly controlled by faults. Based on the systematic analysis of the structural characteristics of the deposit, element association and anomalies of tectonic-geochemistry are discussed in this paper. Trace element concentrations of tectonites shows three element association of principal factors by factor analysis, on behalf of the strata rock elements, medium-high temperature ore-forming fluid and medium-low temperature ore-forming fluid respectively. In the upper parts of the ore bodies, the element association of principal factors is similar, which indicates that the ore bodies formed by the same ore-forming fluids. In the lower part of No.I ore body, the element association of principal factors associated with galena separated from element association associated with sphalerite, which may reflect the change of the ore-forming fluids or superposition of multi-stage ore-forming fluids. R-type factor analyses of tectonites in different level show that barite and lead-zinc mineralization are closely related, and this indicated that the barite is one of important prospecting indicator, which is consistent with field observation. The distribution of tectonic geochemical anomalies can reflect the migration direction of the ore-forming fluid, and provide evidence for ore-finding prediction. In this paper, geological and geochemical prospecting marks of the Songliang lead-zinc deposit are summarized. Targets are delineated on the basis of those prospecting marks, and some of targets have been verified by exploration engineering.