东风山前寒武纪含铁建造金矿床中的稀土元素

THE RARE-EARTH ELEMENTS OF DONGFENGSHANPRECAMBRIAN IRON-BEARING FORMATION GOLD DEPOSIT INHEILONGJIANG PROVINCE

东风山含铁建造金矿床中稀土元素含量普遍较低。东风山群是含矿层，其不同层位岩石和矿物的稀土含量有所差别。大理岩和含铁层中铁闪石的稀土含量最低，甚至低于稀土地壳丰度；上部角岩、下部角岩和石榴子石中稀土含量近似其他壳丰度；而板岩和花岗岩中稀土含量远高于其他壳丰度。稀土元素分布的特点反映了东风山金矿床形成于一个半封闭和较还原的海盆地，金矿化是在弱碱性条件下产生。黄铁矿中出现独居石类矿物，这可能与陆壳重熔改造形成花岗岩时产生的局部富轻稀土热液沿黄铁矿裂隙渗入有关。

The content of rare-earth elements in the Dongfengshan iron-bearing formation gold deposit is generally lower. The Dong-fengshan group is ore-bearing formation. The content of rare-earth elements of rocks and minerals in different horizons of the Dongfengshan group differ substanlly, Marble and grunerite have the lowest rare-earth elements and are lower than their crust abundance. Content of rareearth elements in upper nomstone, under nomstone and gamet is similar to their crust abundance. The content of rare-earth elements of slate and granite is higher than crust abundance. The distribution charactcristics of rare-earth elements indicate that the Dongfengshan gold deposit was formed in a semdcutoff sea basin, It is formed under a reduced environrnent. Gold mineralization occurred in a weak base condition. Occurrence of monazite in pyrite was probably related to the local hydrothermal solutions with rich light rare-earth elements formed under remelting terrestrial crust that was permeated along crack of pyrite.