重庆银矿垭口铝土矿床镓地球化学特征及成矿环境研究

通过对重庆银矿垭口铝土矿床的研究，发现该矿床中镓含量普遍超过了工业综合利用的最低指标，在含矿岩系中均有分布，且镓和Al₂O₃呈弱的正相关关系。通过Sr与Ba比值推断，矿床以陆相沉积为主，沉积过程中有海水的介入；样品Rb/K值小于标准海洋沉积值（0.006），属半咸水海陆过渡带沉积~淡水沉积；U/Th比值和V/Cr比值分别在0.1~0.73和0.5~2.04之间，由此可以判别含矿岩系属于典型氧化环境；对Ni/Co比值的计算发现含矿岩系可能在沉积过程中受到了海水的改造；Ga/Al比值变化范围主要在0.53～1.74，成矿介质酸碱度的变化幅度较小；从含矿岩系矿物组合中含黄铁矿、高岭石等矿物可以推断介质为酸性的可能性较大。稀土元素球粒陨石标准化分布模式表明，轻稀土富集，重稀土亏损，据样品统计，δCe<0.95为负异常的4个样品分布在探槽工程底部，0.95<δCe<1.05为正常的样品个数为3，其余19个为正异常，Eu显示为负异常；总体水介质应以淡水为主、基本处于氧化环境、弱酸性介质。因此该矿床是以陆相沉积、淡水作用为主的海陆交互环境。

Analysis on Gallium Geochemical Characteristics and Ore-forming Environment of Bauxite Mine in Yinkuangyakou of Chongqing

Research on the Chongqing Yinkuangyakou bauxite deposit revealed that gallium is generally more than the lowest indicators of comprehensive utilization of industrial,gallium content of the bauxite deposits in the ore-bearing series are distributed, and gallium to Al₂O₃ weakly positive correlation. Sr/Ba ratio inferred continental sedimentation is main; the result which the sample Rb/K value is less than the standard marine sedimentary 0.006 reflected brackish transitional zone deposition to freshwater deposition; U/Th ratio range 0.1 to 0.73 and V/Cr ratio from 0.5 to 2.04, which can distinguish ore-bearing rock series are typical oxidizing environment; Seawater may influence ore-bearing rock series during deposition by the calculation of the ratio of Ni/Co found; Ga/Al ratio varied from 0.53 to 1.74, the mineralization medium pH changed magnitude smaller; containing pyrite from the ore-bearing rock mineral assemblage, kaolinite and other minerals can be inferred that the medium is acidic likely. Chondrite-normalized distribution patterns shows LREE enrichment and HREE losses, δCe <0.95 ( four samples )is negative anomalies, 0.95 <δCe <1.05 for normal samples 3, 19 positive anomalies,Eu shows negative anomalies; the overall aqueous media should mainly freshwater basic in oxidizing and acidic environment.  The deposit is a continental deposit  with  the main freshwater to  paralic environment.