一种新产状的含铈褐钇铌矿

关于褐钇铌矿族的研究,国内外积累了不少资料。其主要产在黑云母花岗岩、花岗伟晶岩、微斜长石岩、交代变质岩、蚀变花岗岩、白岗岩及花岗岩的残坡积和冲积砂中。1979年我们在进行内蒙白云鄂博铌、稀土、铁矿床物质成分的研究时,在白云石型铌、稀土矿石中发现含铈褐钇铌矿,与该区原已发现的褐铈铌矿等矿物组成了褐钇铌矿-褐铈铌矿系列。

A NEW OCCURRENCE OF CERIUM FERGUSONITE

The cerium fergusonite referred in this paper was found in the Bayan Obo,Inner Mongolia Autonomous Kegion.It occurs in the ore of Nb,TR dolomite type from Bayan Obo group and associates with dolomite,riebekite,magnetite and other rare earth minerals.This mineral belongs to tetragonal system,brown yellow or brown green in color,luster,grease-vitreous,clear to turbid.The grain size is fine,0.02-0.07 mm in diameter.The X-ray powder pattern was weak.As the cerium fergusonite is heating up to 1000℃ the strongest lines are: 3.133 (10),,2.944(8),2.742(8),1.907(7),1.644(6),1.617(6),1.570(7),1.221(5).The unit cell parameters calculated from X-ray powder data are a0 5.06 Å,bo 10.96 Å,Co 5.28 Å.Microprobe analysis gave Nb₂O₅ 42.94%,∑Ce 11.15%,∑Y 38.65%,ThO₂ 3.14%,UO₂1.87%.It is rich in Th but depleted in U.Thus we get the chemical formula as ∑Y_0.8,ECe_0.18 (Th,U,Ca,Mn,Fe)_0.12]_1.11 Nb,Ti]_0.93O₄.The coordinated pattern of REE shows its richness in∑La-Nd,∑ Sm-Ho but depletion in ∑Zr-Lu.This is in accordance with the country rock.The cerium fergusonite discovered in dolomite not only gives us a new occurrence of cerium fergusonite,but also shows the presence of an independent mineral of yttrium in Bayan Obo.