衢州670与660矿区赋矿围岩地球化学特征对比

Comparison on Geochemical Characteristics of Host Rock from 670 and 660 Mining Areas in Quzhou

本文对分处于衢州北部的扬子地块670矿区和南部的华夏地块660矿区的主要赋矿围岩地球化学特征进行了对比,旨在论证其成岩物质来源与成因的异同性,深化火山岩型铀成矿作用理论研究。两个矿区的典型赋矿围岩黄尖组熔结凝灰岩和九里坪组流纹岩的主、微量元素特征表明,赋矿围岩的主量元素均具有富硅、贫钙、贫铁、高钾、富碱、过铝质的特点,具有相似的稀土元素和微量元素地球化学特征,均显示出稀土总量高,轻稀土富集,强烈Eu负异常,强烈的富集Rb,Th,La,Sm,Hf,显著的贫Ba,Sr,P,Ti的特点。研究认为两组岩石虽产于不同大地构造单元,但它们具有相似的成岩物质来源和成因特征,这种相似性可能是分属两个大地构造单元的两组火山岩均有利于铀成矿作用的重要原因。

The geochemical characteristics of main host rock in the northern Yangzi block 670 mining area and southern Cathaysia Block 660 mining area in Quzhou are compared to prove the similarities and differences of material source and genesis,which deepen the theoretical study on volcano rock type uranium mineralization. Research of major and trace elements of the typical host rock from the two mining areas,Huangjian Formation ignimbrite and Jiuliping Formation rhyolitic,shows that,the main elements of host rock from two mining areas are rich in silicon,kalium,alkali and poor in calcium,iron; rare earth and trace elements share similar characteristics,showing high total REE,LREE enrichment,a strong negative Eu anomaly,strong enrichment of Rb,Th,La,Sm,Hf and significant depletion in P,Ti,Ba,Sr. Two formations of rock are produced in different tectonic units,but they have similar diagenetic material source and genesis source characteristics. The similarity may be an important cause of belonging to two tectonic units but both being advantageous to uranium mineralization.