超镁铁岩的REE特点及其对青海德尔尼铜钴矿的成因意义

THE REE CHARACTERISTICS OF ULTRAMAFIC ROCKS AND THIER SIGNIFICANCE TO THE GENESIS OF THE DURNGOI COPPER DEPOSIT, QINGHAI

不同成因的超镁铁岩具有不同的ＲＥＥ特点。与硫化镍矿有关的侵入超镁铁岩有较高的ＲＥＥ含量，富集轻稀土；蛇绿岩套中的变质橄榄岩ＲＥＥ含量较低，以“Ｕ”型或轻稀土亏损型为特点。德尔尼超镁铁岩体有变质橄榄岩的ＲＥＥ特征，属蛇绿岩套的一部分，为地幔物质低度部分熔融的产物，部分熔融程度约为５％。德尔尼铜矿属火山成因的块状硫化物矿床，由于构造作用致使矿体产于超镁铁岩中。阿尼玛卿山地区铜钴矿的找矿方向是原布青山群和部分三叠系中玄武岩－硅质（碳质）板岩出露地区。

Various ultramafic rocks with different genesis illustrate various characteristics of rare earth element. The intrusive ultramafic bodies related to nickel deposits have higher concentration of REE with enrichment of LREE. The metaperidotite in ophiolite suit is characterized by lower REE content and the "U" type of variation or deletion of LREE. The Durngoi ultramafic rocks distributed in Qinghaiare similar to the metaperidotite in REE, and belong to part of the ophiolite suite.It might be the product of lower partial melting of mantle, the partial melting degree accounting for 5 %. The Derngoi copper deposit is of volcagenic massive sulfide deposite, and the occurrencce of it in the ultramafic rocks is due to tectonic movement. In the Animaqin zone, the prospecting areas are the exposure places of Buqingshan Group of Lower Permian basalt and siliceous or carbonaceous slate of Triassic System.