赣南大埠岩体地球化学特征及铀、钨成矿潜力分析

Geochemical characteristics and prospecting potential for uranium and tungsten of Dabu intrusion, Southern Jiangxi Province, China

大埠岩体内及近外围铀、钨矿产信息丰富.地球化学特征显示大埠岩体花岗岩呈钙碱性、过铝质,具高硅（73.73％～77.89％）、富钾（3.99％ ～ 5.60％）和低钙（0.107％ ～ 0.660％）含量特点,铝饱和指数A/NCK为1.04～ 1.25、里特曼指数δ为1.66 ～ 2.34,稀土元素总量低（∑REE=37.28×10-6～ 177.49×10.6）,稀土元素球粒陨石标准化图解表现为左高右低、具强负铕异常的“V”字型,大离子亲石元素K、Rb、Th、Sr等富集,Ta、P、Ti亏损,这些特点说明岩体的形成是古老陆壳物质熔融的结果.岩体地球化学特征与华南产铀花岗岩和含钨花岗岩地球化学特征相似,结合近年来铀、钨矿勘查取得的新成果,认为大埠岩体具较大的铀、钨成矿潜力.

There is abundant mineralization information about U and W within the Dabu intrusion and near pcriphery of it. It is showed that the granite of Dabu intrusion is calcalkaline and peraluminous. It has a high-silicon （73.73% - 77.89%）, rich potassium （3.99% - 5.60%） and low-calcium （0.107% - 0.662%） characteristic in content. Its aluminium saturation index A/NCK is 1.04 - 1.25 and Rittmann index B is 1.66 - 2.34. The total rare earths is low （∑ REE=37.28 - 177.49 ppm）. The ehondrite-normalized REE pattern graph is a ＂V＂-type whose right is higher and left is lower, and the europium is obviously negative anomaly, and it is rich in the LILE such as K, Ru, Th, Sr and poor in Ta, P and Ti. These geochemical characteristics show that the formation of the intrusion is result in the melting of the primeval continental material. The geochemical characteristics of the Dubu intrusion are similar to those of the uranium-occarring granites and the tungstiferous granites in South China. Combining with the new fruits on the U and W prospecting, it is believed that Dabu intrusion possesses greater prospecting potential.