| 内蒙古黑鹰山富铁矿床磷灰石稀土元素地球化学特征 |
| |
| 关键词:high-grade iron deposit apatite rare earth element ore genesis Heiyingshan Inner Mongolia |
| 基金项目:国家自然科学基金项目（编号：40073015）;国家地质调查项目（编号：K1.3.32） |
|
| 摘要点击次数: 3451 |
| 全文下载次数: 2171 |
| 摘要: |
| Rare Earth Element Features of Apatite Separated from the Heiyingshan High-Grade Iron Deposit, Inner Mongolia |
| Located at southeastern part of the Hongshishan-Heiyingshan terrane within the Kazakhstanian-Beishan plate, the Hei-(yingshan) deposit is one of the most important high-grade iron deposits in northwestern China. Iron mineralization occurs within Early Carboniferous dacite, rhyolite, dacitic lava and brecica of Baishan Formation in the forms of massive blocks, stratoid layers, lens and veins. The iron-bearing intermediate-acid volcanic sequences are cut by a number of Hercynian mafic and granitoid dykes and controlled by quite a few NE- and EW-trending fracture or fault zones. Individual iron orebodies can be traced along the strike for 115 to 200 m, and downdip for 100 to 200 m, being 4 to 12 m in thickness. Moreover, several independent yttrium orebodies were found within the iron deposit. Although apatite predominates over iron-bearing minerals, no difference has been observed between the iron and yttrium orebodies in geological setting, wall rock, mineral assemblage and attitude. Mineralogical composition of both iron and yttrium ores is relatively simple, consisting of magnetite, hematite and trace amounts of pyrite. Gangue minerals include apatite, quartz, chlorite, and hornblende. Eight apatite separates from the massive and vein type iron ores were selected for REE analysis. The REE content of the eight apatite samples ranges from 14 776×10-6 to 21 313×10-6, four times that of the apatite separates from the Ningwu iron deposit in the lower and middle Yangtze valley and the Kiruna iron deposit in Sweden. LREE/HREE and δEu values of these eight apatite separates are 8.31～9.18 and 0.37～0.40, respectively. All these apatite samples show an overall negative chondrite-normalized REE slope and negative Eu anomalies. Combined with Sm-Nd isotopic data of apatite separates as well as other field and geological evidence, the authors believe that the ore-forming materials of the massive iron ores might have been formed by a mixed source of depleted mantle- and crustal-derived magma or fluids. In contrast, the vein type iron ores were probably derived from the mantle-related ore fluids. |
| NIE Feng-jun,JIANG Si-hong,LIU Yan.2005.Rare Earth Element Features of Apatite Separated from the Heiyingshan High-Grade Iron Deposit, Inner Mongolia[J].Acta Geoscientica Sinica,26(5):435-442. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|