贵州遵义锰矿床地球化学特征及成因分析  

Geochemistry and Ore Genesis of Zunyi Mn Deposit, Guizhou Province, China

作　　者：刘志臣[1,2] 王聪[2] 张远国[2] 范波[2] 陈登[2] 魏泽权[2] 崔忠强[2] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]贵州省地矿局102地质大队,贵州遵义563003

出　　处：《矿物学报》2015年第4期481-488,共8页Acta Mineralogica Sinica

基　　金：贵州省地质矿产勘查开发局地质科研项目(黔地矿科合[2011]3号);贵州省遵义锰矿国家级整装勘查项目(2013)

摘　　要：遵义锰矿为我国南方重要的沉积型锰矿之一,其矿石自然类型为碳酸盐岩型锰矿石,工业类型为高硫、中-高铁、低磷和低硅贫锰矿石。本文在选取典型钻孔所揭露含锰岩系详细观察的基础上,对锰矿石及其顶、底板岩石,进行了较为系统的主-微量和稀土元素以及碳-氧同位素组成分析。本区锰矿石主量元素中Fe/Ti为12.35~140.5,平均59.35（〉20）,（Fe＋Mn）/Ti为153.88~520.5,平均271.05（〉25）,Al/（Al＋Fe＋Mn）为0.05~0.20,平均0.12（〈0.3）,表明锰矿石的形成与海底热液活动密切相关。锰矿石的U和Th平均含量分别为6.37×10-6和2.79×10-6,U/Th均值为2.52（〉1）,Ni和Co平均含量分别为191.9×10-6和93.03×10-6,Ni/Co均值为2.16（〈3.6）,具有热水沉积特征,∑REE变化为123.54×10-6~424.08×10-6,普遍小于200×10-6,总量较低,配分型式表现为右倾型,∑LREE/∑HREE比值变化为2.23~119.22,明显大于1,（La/Yb）N比值4.58~18.83,负Ce异常（δCe=0.45~0.72）,与热水沉积锰矿稀土特征相似。综合矿床地质、地球化学特征,认为锰矿石及其底板硅质岩为海底热水沉积成因,并混有少量化学沉积物,而其顶板岩石属非热水沉积成因。Zunyi Mn deposit is one of important sedimentary manganese deposits in the South China. Its natural type of ores is carbonate manganese, with high sulfur, high-low phosphorus and low silicon iron lean manganese. In this paper, on the basis of detailed observations of manganese ore major, trace and rare earth elements and carbon-oxygen isotope composition were analyzed. Results show that Fe/Ti values range from 12.35 to 140.50, with the mean of 59.35（〉20）;（Fe＋Mn）/Ti values range from 153.88 to 520.5, with the mean of 271.05（〉25）; and Al/（Al＋Fe＋Mn） values range from 0.05 to 0.20, with the mean of 0.12（〈0.3）, suggesting that the manganese ore is closely tied to hydrothermal activity. As for the trace elements, it is noted that the mean U and Th contents are 6.37×10-6 and 2.79×10-6, respectively and average U/Th is 2.52（〉1）. Similarly, mean Ni and Co contents are 191.90×10-6 and 93.03×10-6, respectively and the mean Ni/Co value is 2.16（〈3.6）, similar to the characteristic of hydrothermal deposits. In addition, total REE contents range from 123.54×10-6 to 424.08×10-6, with most values lower than 200×10-6, belonging to LREE-enriched type with ∑LREE/∑HREE ranging from 2.23 to 119.22（〉1）,（La/Yb）N ranging from 4.58 to 18.83, and negative Ce anomaly（0.45 to 0.72）, indicating its hydrothermal origin. According to the ore deposit geology and geochemical characteristics of ore deposits, manganese ore and its bottom siliceous rocks are originated from submarine hot water deposition formation, in the process of sedimentary mixed with a small amount of the normal biological chemical deposition, with the roof rock of a hot-water sedimentary origin.

关 键 词：主-微量和稀土元素 热水沉积 矿床成因 遵义锰矿 

分 类 号：P59[天文地球—地球化学] P618.32[天文地球—地质学]