江西雅山414和灵山松树岗钽铌矿成矿特征对比分析研究

Contrasting Metallogenic Geological Characteristics of Yashan 414 and Lingshan Songshugang Ta-Nb Deposits in Jiangxi

雅山414和灵山松树岗钽铌矿是我国两个超大型以钽铌为主的稀有多金属矿床,两者都处于钦杭成矿带江西段内,属花岗岩型钽铌矿,分布于小型岩株的顶突部位,为似层状厚大矿体。通过对比分析研究,发现两者在诸多相同成矿特征的基础上尚有许多细微差别。雅山414钽铌矿钠长石化蚀变由上至下递减,而松树岗钽铌矿正好相反,由上至下是递增的;雅山414钽铌矿有用组分的含量总体上由上至下逐渐降低,而松树岗钽铌矿由上至下,铌含量缓慢升高,钽和铷的含量缓慢降低;雅山414钽铌矿有用组分数量比松树岗钽铌矿更多,多出了铯和铍,且伴生组分锂、铷的含量更高,但主矿产钽和铌的含量远不及松树岗钽铌矿高;雅山花岗岩为晚侏罗世陆内造山挤压环境下形成的S型花岗岩,灵山松树岗隐伏花岗岩为早白垩世地壳拉张环境下形成的A型花岗岩,具有更多的幔源物质参与,两者原始岩浆的成因差异,造成了岩矿石化学成分上的差异,松树岗钽铌矿SiO_(2)、Fe_(2)O_(3)、MgO、S、W、Sn以及以硫化物矿物形式存在的Pb、Zn、Ag等元素的含量比雅山414钽铌矿高,但Al_(2)O_(3)、CaO、Na_(2)O、P_(2)O_(5)的含量明显低;松树岗隐伏岩体的顶部还有一层厚为15~170 m的云英岩化花岗岩,矿石中含水含氟矿物多,反映矿床矿化蚀变环境温度降低缓慢,蚀变作用持续时间长,蚀变强度大,蚀变范围广,蚀变矿物种类多。

Yashan 414 and Lingshan Songshugang Ta-Nb deposits are two super large rare polymetallic deposits in China.Both of them are located in the Jiangxi Section of Qinhang metallogenic belt.They are granite type Ta-Nb deposits distributed in the top outburst part of small rock stock,and they are bedded thick ore bodies.On the basis of comparison,there are many differences between them.The albitization alteration of Yashan 414 Ta-Nb deposit decreases from top to bottom,while that of Songshugang Ta-Nb deposit increases from top to bottom.The content of useful components in Yashan 414 Ta-Nb deposit decreases gradually from top to bottom,while that of Songshugang Ta-Nb deposit changes extremely slowly,namely,Nb,Ta and Rb content decreases slowly.Yashan 414 Ta-Nb deposit has more useful components than Songshugang Ta-Nb deposit.and there are more Cs and Be,and the content of associated components Li and Rb is higher,but the content of Ta and Nb in the main ore is far less than that in Songshugang Ta-Nb deposit.Yashan granite is an S-type granite formed in the late Jurassic intracontinental orogenic compression environment.The Lingshan Songshugang concealed granites are A-type formed in the early Cretaceous crustal extension environment,with more mantle derived materials involved.The genetic differences between the two original magmas lead to the differences in the chemical composition of rocks and ores.The contents of SiO_(2),Fe_(2)O_(3),MgO,S,W,Sn and Pb,Zn,Ag in sulfide minerals in the Songshugang Ta-Nb deposit are higher than those in Yashan 414 Ta-Nb,but the contents of Al_(2)O_(3),Cao,Na_(2)O and P_(2)O_(5) are obviously lower.There is a layer of greisenization granite with a thickness of 15~170 m at the top of the concealed rock mass of Songshugang,with a large amount of water-bearing and fluorine-bearing minerals in the ore,which reflects that the temperature of the mineralization and alteration environment of the deposit decreases slowly and lasts for a long time,and that the alteration intensity is strong,the alteration range is large,and the types of altered minerals are various.