浙江八面山萤石矿床稀土元素地球化学特征及成因探讨

对浙江八面山萤石矿床中不同类型萤石矿石和围岩样品的稀土元素的系统分析表明,细粒萤石矿石的ΣREE〈39×10-6,LREE为14.36×10-6～34.24×10-6,HREE0.96×10-6～2.04×10-6,Y〈3×10-6;巨晶萤石矿石中的ΣREE3.62×10-6～20.81×10-6,LREE2.71×10-6～17.67×10-6,HREE0.24×10-6～1.49×10-6;而围岩花岗岩的ΣREE460.29×10-6,LREE225.97×10-6,HREE91.32×10-6,Y＆gt;140×10-6;沉积岩中的ΣREE20.22×10-6、LREE16.11×10-6、HREE1.61×10-6。矿石与围岩中沉积岩的稀土总量、轻稀土、重稀土和Y的含量接近,与花岗岩的稀土总量、轻稀土、重稀土和Y元素含量相差悬殊。萤石矿石的稀土分布型式主要为轻稀土富集型,（La/Yb）N通常多数大于8,在8.07～17.26间,δEu值在0.45～1.30,δCe在0.89～1.14间,Ce、Eu基本不显异常。矿石与围岩的稀土地球化学研究显示,八面山萤石矿床为受地层、岩体与断裂共同控制＂三位一体＂的低温热液型矿床。

GENESIS DISCUSSION AND REE GEOCHEMISTRY CHARACTERS IN BA-MIANSHAN FLUORITE DEPOSIT IN ZHEJIANG PROVINCE

It is shown,on the testing results of REE in different types fluorite ores in the Ba Mianshan fluorite deposit and its country rocks,that the ΣREE <39 ×10 –6,LREE 14.36×10–6～34.24×10–6,HREE 0.96 ×10 –6～ 2.04×10–6,Y<3×10–6 in granule flurite ores,and ingotism fluorite ores with the ΣREE 3.62×10–6～ 20.81×10–6,LREE 2.71×10–6～17.67×10–6,HREE 0.24×10–6～1.49×10–6,the country rock granite with the ΣREE 460.29×10–6,LREE 225.97×10–6,HREE 91.32×10–6,Y>140 ×10–6,and sedimentary rock with the ΣREE 20.22×10–6 LREE 16.11×10–6 HREE 1.61×10–6.The contents of ΣREE,LREE and HREE and Y in fluorite ores approach to its contents in sedimentary rocks of country rocks,but with wide gap in granite . REE distribution pattern of fluorite ores shown as enrichment of LREE,LREE value varies at 8.07 to17.26,δEu varies at 0.45 to1.30,within 0. 89～1.14,Ce and Eu without exception. The above chemical study on REE shows its low temperature and hydrothermal genesis and the Ba Mianshan fluorite deposit controlled by the activities of stratum and rock body and interstratal fracture.