西藏冈底斯成矿带成矿规律

Metallogenic regularity of Gangdese Metallogenic Belt,Tibet

冈底斯成矿带是中国西部最重要的成矿带之一,目前已探获的铜金属资源量大于3000万t、铅锌金属资源量大于730万t。前人对该带成矿地质条件、成矿规律、成矿理论等研究取得了创新性、突破性的成果,文章结合成矿带最新勘查和研究进展,开展了以下总结工作:(1)划分了矿床类型。成矿带已发现的矿床类型包括:斑岩型铜金、铜钼、钼(铜)矿床,矽卡岩型铜、铅锌、铁、钨钼矿床,浅成中-低温热液型铅锌银、铯、自然硫矿床,沉积型石膏、煤等;(2)收集汇总了矿床成岩成矿高精度年龄学数据,总结了成矿时代分布规律,划分了石炭纪、晚三叠世—侏罗纪、早白垩世晚期—晚白垩世早期、晚白垩世晚期—始新世早期、渐新世、中新世、第四纪7个成矿期;(3)总结了不同矿床类型的空间分布规律,探讨了矿床东西向成带、南北向成串的控制因素;(4)收集了典型矿床金属硫化物的硫、铅同位素数据,探讨了成矿物质来源对成矿元素的影响:幔源物质→壳幔混合物质→壳源物质依次对应了CuAu→Cu-Mo→Pb-Zn成矿元素的分布;(5)厘定了5个成矿系列,包括冈底斯与晚古生代沉积成矿作用有关的石膏矿床成矿系列;冈底斯与印支晚期—燕山早期中酸性岩浆成矿作用有关的Cu、Au、Ag、Fe矿床成矿系列;冈底斯与晚中生代沉积成矿作用有关的煤矿床成矿系列;冈底斯与喜马拉雅期岩浆成矿作用有关的Cu、Mo、Pb、Zn、Au、Ag、W、Fe、Co矿床成矿系列;冈底斯与新生代沉积成矿作用有关的砂金矿床成矿系列;(6)探讨了区域构造演化与成矿的关系。

The Gangdese metallogenic belt is one of the most important metallogenic belts in West China.At present,the explored copper metal resources are more than 30 million tons,and lead-zinc resources are more than 7.3 million tons.Previous researches on metallogenic geological conditions,metallogenic regularity,and metallogenic theory have made innovative and breakthrough achievements.Combined with the latest exploration and research progress of this metallogenic belt,this paper has carried out the following summary work:(1) the types of deposits are divided.The types of deposits discovered in this metallogenic belt include porphyry Cu-Au,Cu-Mo,and Mo(Cu) deposits,skarn Cu,Pb Zn,Fe,W-Mo deposits,epithermal medium-low temperature Pb-Zn-Ag,Cs,and natural S deposits,sedimentary gypsum,and coal,etc;(2) The high-precision age data of rock-forming and mineralization are collected.The distribution regularity of metallogenic ages is also summarized.It can be summed up in seven metallogenic periods:Carboniferous,Late Triassic-Jurassic,late Early-Cretaceous-early Late-Cretaceous,late Late-Cretaceous-Early Eocene,Oligocene,Miocene,and Quaternary;(3) The spatial distribution regularity of different deposit types are summarized,and control factors of deposit zonation in east-west direction and string in north-south direction are discussed;(4) The sulfur and lead isotopic data of metal sulfide minerals in typical deposits are collected,and the influence of metallogenic material source on metallogenic elements have discussed:mantle-derived material→crust-mantle mixed material→crust-derived material corresponds to the distribution of Cu-Au→Cu-Mo→Pb-Zn metallogenic elements in turn;(5) Five metallogenic series are determined,namely:Metallogenic series of gypsum deposits related to late Paleozoic sedimentary mineralization;Metallogenic series of Cu,Au,Ag,and Fe deposits related to intermediate-acid magmatic mineralization from late Indosinian period to early Yanshanian period;Metallogenic series of coal deposits related to Late Mesozoic sedimentary mineralization;Metallogenic series of Cu,Mo,Pb,Zn,Au,Ag,W,Fe,and Co deposits related to Himalayan period magmatic mineralization;Metallogenic series of placer gold deposits related to Cenozoic sedimentary mineralization;(6) The relationship between regional tectonic evolution and mineralization is discussed.