长江中下游成矿带含稀散金属矿床特征初探

稀散金属是关键金属的重要部分,其矿化特点和成矿规律等方面受到矿床学界高度关注。文章总结了全球稀散金属矿化类型和分布规律,除了镓、镉和铊矿床外,其他锗、硒、铟、碲和铼5种稀散金属普遍伴生于斑岩-矽卡岩铜矿系统。笔者初步地绘制了全球斑岩型和矽卡岩型稀散金属的分布图、长江中下游成矿带含稀散金属矿床的分布图,指出长江中下游成矿带有2种不同类型含稀散金属矿床:一类呈伴生产于斑岩-矽卡岩铜铁金和铅锌矿床,以多种稀散金属为特征;另一类呈独立稀散金属矿床;以前者为主。文章以长江中下游矿成矿带鄂东南丰山矿田为例,介绍碲和铊的赋存状态,初步地建立了矽卡岩铜金碲矿床+远接触带低温金铊碲矿床组合模型。最后提出矽卡岩型稀散金属矿床重点关注的科学问题,建议加强氧化型含金矽卡岩矿床伴生的稀散金属矿床的成矿机制研究。

A preliminary study of characteristics of dispersed metal-bearing deposits in Middle-Lower Yangtze River Metallogenic Belt

Dispersed metals constitute an important part of critical metals, and have become critical mineral resource in-ternationally. Their mineralization characteristics and metallogenetic regularity have aroused much interest among economic geologists. In this paper, the authors summarize the mineralization characteristics and distribu-tion of dispersed metals all over the world. Except gallium, cadmium and thallium, the other five dispersed metals including germanium, selenium, indium, tellurium, and rhenium are genetically associated with porphyry-skarn systems. The authors'' study has outlined the distribution of porphyry and skarn dispersed metal deposits in the world as well as in the Middle-Lower Yangtze River Belt. Two different types of dispersed metal deposits in the Middle-Lower Yangtze River Belt were recognized:one consists of dispersed metals as by-products in porphyryskarn Cu-Fe-Au or Pb-Zn deposits, and the other comprises dispersed metal-only deposits. Abundant telluride minerals are present in the Cu-Au skarn and distal Au-Tl deposits in the Fengshan area in the Middle-Lower Yangtze River Metallogenic Belt, and the genetic model of linkage between Cu-Au-Te skarn and distal Au-Tl-Te deposit is proposed. Critical scientific issues on skarn dispersed metal deposits are pointed out and suggestions for strengthening of further studies of the metallogenic mechanism of oxidized gold-bearing skarn deposits with dispersed metal by-products are put forward.