相山火山盆地南部印支期富铀岩体岩石学及主微量元素特征  

Petrology and major-trace elements characteristics of the Indosinian uraniumrich pluton in southern Xiangshan volcanic basin

作　　者：周万蓬[1,2,3] 范洪海 刘林清[2,3] 姜勇彪[3] 

机构地区：[1]核工业北京地质研究院,北京100029 [2]江西省数字国土重点实验室,江西南昌330013 [3]东华理工大学地质调查研究院,江西抚州344000

出　　处：《中国地质》2015年第6期1897-1909,共13页Geology in China

基　　金：中国地质调查局工作项目(1212011120836)和(1212011220248)资助

摘　　要：通过对咸口岩体进行岩石学、主微量元素分析,发现其为一套印支期富铀复式岩体,具富硅、高钾、弱过铝质特征,属高钾钙碱性系列岩石;其稀土元素配分型式具右倾斜特征,富轻稀土,轻稀土分馏比重稀土明显,铕亏损明显;微量元素Nb、Ce、Pr、Zr、Ba明显亏损,而Rb、Th、U、Pb、Ta、Nd、Hf元素富集,Rb/Sr比值变化大（0.92~6.52）;岩体平均铀含量为19.55×10-6,属富铀花岗岩体。由主微量元素构造环境判别,结合区域地质背景分析,咸口岩体为板内后造山构造环境下形成的富铀花岗岩体。相山南部咸口富铀岩体的发现为解决相山铀矿田的铀源问题提供了新的思路,也有望指引在相山南部寻找花岗岩型铀矿床。Petrology and major- trace elements analysis shows that Xiankou pluton is a compound granitic body characterized by high Si O2, high K and slightly peraluminous nature, thus belonging to the high-K calc-alkaline series. Chondrite-normalized REE patterns are characterized by right-inclined shape, rich light rare earth, significant negative europium anomalies, and more obvious fractionation of LREE than that of HREE. Trace elements are characterized by rich Rb, Th, U, Pb, Ta, Nd, Hf, obviously poor Nb,Ce, Pr, Zr, Ba, and significant variation of Rb/Sr ratio（0.92~6.52）, with the average uranium content being 19.55 ppm, suggestingthat the pluton belongs to uranium- rich granite. The tectonic setting discrimination diagram of trace elements and main elements shows that Xiankou pluton is a uranium- rich granite formed in an environment of intraplate post- orogensis. The discovery of Xiankou pluton provides a new train of thought for resolving the uranium source problem of the Xiangshan uranium orefield, and might guide the prospecting for granite type uranium deposits in southern Xiangshan.

关 键 词：咸口富铀岩体 地球化学 印支期 相山 

分 类 号：P619.14[天文地球—矿床学]