陕西凤太地区铅锌矿床关键控矿要素探讨

Discussion on the Ore-Controlling Factors of Lead-Zinc Deposits in the Feng-Tai Area,Shaanxi Province

本文从陕西凤太矿集区容矿盆地的地层和沉积建造入手,对本区找矿勘探密切相关的赋矿层位、容矿岩、矿床建构样式和矿化分带等原生控矿要素和矿化空间特征进行了梳理与分析,认为凤太地区铅锌矿应属于盆地热卤水喷流沉积矿床;成矿后区域挤压和盆地反转,导致容矿沉积建造发生褶皱变形与浅变质,也使一些矿体最终定位于褶皱枢纽及附近两翼;但成矿后褶皱变形对原生沉积喷流成矿系统的完整性并无重大改变。鉴于上述认识,建议今后的找矿勘探应减少对成矿后"背斜控矿"现象的过度依赖,应重视沉积喷流成矿系统原生控矿要素的分析与研究,并借助沉积喷流矿床特有的原生地球化学向量、找矿线索与找矿标志,配合有效的深部地球物理探测技术,切实将成矿规律和矿床成因认识转化为勘查找矿的工具。

This work focuses on the Sedex Zn-Pb deposits in the Feng-tai region,Southern Qinling,Shaanxi Province.We analyze the basin sedimentary sequences,host horizons and rocks,deposit architectures and zoning patterns of this area,which are the principal original ore-controlling elements and spatial attributes of Zn-Pb mineralization critical to mineral exploration.Our study suggestes that post-mineralization regional compression regime and basin reversion resulted in folding,faulting and low-grade metamorphism of the hosting sedimentary sequences of Devonian age,thus making some ore-bodies relocate at the hinges and ambient wings of anticlines.However,the post-mineralization tectonics did not alter the integrity of the Sedex deposits generally.By this reason,it is suggested that much more attention should be paid on the original ore-controlling elements of the Sedex systems with decreasing reliance on“anticline-controlling-ore”in previous ore-finding practices.At the same time,the geochemical vectors,ore-finding indicators and criteria derived from local Sedex deposits are strongly recommended to integrate into future regional exploration.